Avro Aircraft since 1908

A.Jackson - Avro Aircraft since 1908 /Putnam/

Roe I Biplane

  A. V. Roe's first man-carrying aircraft was a canard biplane of wire braced, wooden construction, similar to the Wright-type model with which he won ?75 at Alexandra Palace in April 1907. The aircraft was built round a large white wood, three bay, triangular structure mounted on four home-made pneumatic tyred wheels, the front pair being steerable. The pilot sat in the forward part of the machine and a 9 h.p. J.A.P. aircooled motorcycle engine was situated amidships, driving a two bladed paddle-like pusher airscrew through five feet of extension shafting which formed the apex of the central structure. Wing construction was primitive, the main spars being external and therefore thin to reduce drag. For rigidity it was necessary to employ a large number of bracing wires and kingposts with the result that the cotton covering could only be applied to the underside of each wing. The covering was then tightened with a coat of size and the whole wing structure braced from three much taller kingposts. There were no ailerons and no rudder but a car-type steering column warped and pivoted the large front elevator and so gave both lateral and fore-and-aft control. A. V. Roe was the true inventor of the single-lever type of control and had patented such a system as early as 1906, ante-dating the claims of Continental inventors by several years.
  The Roe I biplane was built in the stables behind the surgery of A. V. Roe's brother Dr. S. Verdon Roe at 47 West Hill, Putney, London, and on completion in September 1907 was taken to Brooklands, where Roe hoped to make an attempt to win the ?2,500 prize offered by the owners for the first flight round the track before the end of that year. Although a great deal of taxying was done along the concrete track, the 9 h.p. engine was not powerful enough and the biplane flew only when towed by friendly racing motorists. Such flights were successful on straight tows, but turns resulted in sideslips and damage until Roe designed a quick-release which enabled him to cast off at will and make controlled landings. In this way he learned the feel of the controls but the end of the year came without the prize being awarded.
  'A.V.' then negotiated the loan of a 24 h.p. Antoinette eight cylinder, water cooled engine designed and built in France by Levasseur. It had copper water jackets and direct petrol injection and on its arrival in May 1908, gave Roe the extra power he so badly needed. To carry the increased weight, extra wing area was provided by inserting short stub wings at mid gap in the inner wing bays. Unfortunately the extra power was more than his airscrews could absorb and many blade failures occurred, but the trouble was eventually cured and in the early morning of June 8, 1908, he succeeded in taking the biplane off under its own power and in making several hops at a height of 2 to 3 ft. above the track. A. V. Roe did not publicise his achievement and two years passed before he let it be known that he had left the ground in 1908. In 1928-29 the Gorrell Committee of the Royal Aero Club disallowed his claim to have been the first to fly in Britain on the grounds that he had not been airborne for a sufficient distance, ruling that the first Briton to do so had been J. T. C. Moore-Brabazon in a Voisin biplane at Eastchurch nearly a year later.
  During his long stay at Brooklands Roe received no encouragement from his landlords. The Clerk of the Course, E. de Rodakowsky, put every possible obstacle in his way and was openly hostile to aeroplanes, so that when the 1908 motor racing season opened, Roe's shed was pressed into use as a refreshment room and the biplane banished to a field behind the track. Track attendants stumbled under the load while lifting it over the fence and dropped the machine into a dried-up dyke where it was damaged beyond repair. Roe was heartbroken but received no compensation and was forced to send the engine back to France as he could not afford to buy it. He dismantled the remains of the aircraft, keeping only a wheel and a few other selected parts to remind him of some of the ingenious constructional methods he had used. In later years these items were preserved in a glass case at his home as a part of the Roe private aeronautical collection.

  Construction: By A. V. Roe at 47 West Hill, Putney, London, S.W.15
  Power Plants:
   One 9 h.p. J.A.P.
   One 24 h.p. Antoinette
  Dimensions: Span 30 ft. 0 in. Length 23 ft. 0 in.
   Tare weight 350 lb. All-up weight 650 lb.
   Weight of Antoinette engine (without radiator) 98 lb.
Roe I Triplane

  In partnership with J.A.P. engine designer J. A. Prestwich, A. V. Roe next made an abortive attempt to complete a triplane with square section fuselage and triplane tail. A 35 h.p. engine would have been needed and this they could not afford. The partnership consequently dissolved and the fuselage, wings and undercarriage went under the hammer at Friswell's for ?5 10s.
  Lack of funds thus compelled Roe to design his next aeroplane round the same heavy 9 h.p. J.A.P. engine which had first powered the Roe I biplane and to build it of wood instead of light gauge steel tubing as intended. The design was a generally similar, but much more elegant, version of the Voisin brothers' clumsy Goupy II tractor triplane, with a fuselage of three deal longerons with cross struts which formed a strong, wire braced, triangular section girder. The main undercarriage consisted of two cycle wheels in reversed forks with a smaller cycle wheel under the tail.
  Fore and aft movement of a lever gave control in the pitching plane by changing the mainplane incidence, and lateral control by a side to side movement which warped the centre mainplane. This in turn warped the other two mainplanes through push rods. The incidence of the large triplane tail unit was intended originally to vary in unison with that of the mainplanes but the tail was eventually fixed rigidly to the fuselage. There were no movable surfaces but large vertical fins were fitted between the interplane struts of the tail unit. A 9 ft. diameter, four bladed airscrew mounted on a shaft some 3 ft. above the engine, was driven sometimes by motorcycle belt and sometimes by chain, using different sized pulleys or sprockets to give a variety of gear ratios.
  The outer 6 feet of wing panel folded back for ease of transport and housing, other refinements including the suspension of the pilot's seat and petrol tank wholly within the fuselage on rubber webbing made in H. V. Roe's Bulls Eye Braces factory. This feature gave rise to the legend "Bulls Eye Avroplane" painted on the sides of the fuselage, an inscription which contracted rapidly into the Avro trademark so well known today.
  The components of the Roe I triplane were made at Putney in May 1909 and erected with the assistance of E. V. B. Fisher and R. L. Howard Flanders at Lea Marshes, Essex, where A. V. Roe had rented two railway arches and converted them into workshops. On the first two hops the triplane heeled over and smashed the port wing tips because the pilot lacked experience and failed to warp and lift the wing quickly enough. As soon as the cause of the trouble was realised, Roc began (in his own words) "making dozens of short flights up to 50 ft. in length at a height of 2-3 ft. which were hardly more than jumps". The first of these jumps was made on June 5, 1909. Once airborne there was insufficient power for sustained flight and further experimenting took place with different gear ratios and airscrews of varying diameter and blade width, adjustable for pitch on the ground. Results of these trials were carefully recorded and in the course of further hops Roe discovered the need for a small rudder and learned how to improve acceleration by avoiding excessive use of the fore-and-aft control on take-off. He flew 100 ft. on July 13, 1909 and on Friday July 23, at the second attempt, made a much improved take-off and flew 900 ft. at an average height of 10 ft. Two more flights of this length were achieved on the same day and A. V. Roe thus had the distinction of making the first flight over British soil in an all-British design powered by a British engine.
  Although nominally of 9 h.p., his well worn power plant was so oversize internally that it was then giving 10 h.p., a simple development which has led, many times, to the erroneous conclusion that Roe built a later triplane with a 10 h.p. J.A.P. engine. This old power unit weighed 150 lb. with accessories, so that Roe's flights were a remarkable achievement indeed, for at an all-up weight of 500 lb. the power loading was at least 50 lb. per h.p.
  Flights continued throughout August and the fuselage was covered with yellow oiled paper. Later the vertical tail surfaces were removed. Greatly encouraged by his success, Roe then built a near identical second triplane fitted with his new 20 h.p. J.A.P. four cylinder, aircooled engine. This aircraft closely resembled a design which gained him a mark of 74% and second prize in a competition organised by the magazine Aeronautics in July 1909, and both triplanes were entered for the all-British prize at the Blackpool Race Meeting of October 18-24, 1909. Here the original machine carried competition number 14 on the rudder and was promptly christened "Yellow Peril" by the spectators on account of its all-yellow covering, but unfortunately the oiled paper was seriously affected by incessant rain and sagged to such an extent that Roe's only flying comprised a few short hops of up to 150 ft., made on October 19. Although he hurriedly erected the untried second machine and had it ready to fly on October 21, storms prevented further flying and the all-British prize was not awarded.
  Blackpool Week 1909 ended the active career of the first Roe I triplane. It made a brief reappearance at an aero exhibition held at Belle Vue Gardens, Manchester, January 1-3, 1914, spent 11 years in storage at the Manchester factory, and was presented in 1925 to the Science Museum at South Kensington, London where it remains on permanent exhibition.
  The airframe of the second Roe I triplane closely resembled that of the first but fortunately there were several prominent recognition features which made it easily distinguishable from its forebear. Whereas the earlier aircraft had a fuselage of constant depth and large tail wheel, the second fuselage was tapered towards the rear and equipped with a long tail skid. There were also additional struts in the undercarriage. The first machine had a small fuel tank mounted on a fuselage longeron but the second had a narrow, cigar-shaped tank on struts ahead of the pilot to give a greater head of fuel. It must also be remembered that only the first triplane bore the fuselage inscription "Bulls Eye Avroplane" under which appeared a clearly painted figure 3, indicating that the inventor regarded it as his third individual aeroplane. He had meanwhile been evicted from Lea Marshes and on his return from Blackpool, transferred to Old Deer Park, Richmond, Surrey. The new site proved unsuitable and late in November 1909 he moved to Wembley Park, Middlesex, where on December 6 the second Roe I triplane made its first exploratory flights with encouragingly few mishaps. The 20 h.p. J.A.P. (the actual output of which was more like 14 h.p.), improved the performance to the point where local authorities sportingly felled a number of trees to enable him to fly a circular course and land back at his starting point. Attempts to improve the control system were not always successful as on Christmas Eve 1909 when Roe found it impossible to lift the port wings quickly enough and sideslipped into the ground, once more demolishing the port mainplanes.
  In January 1910, with financial help from his brother H. V. Roe, the private firm of A. V. Roe and Company was formed with workshop space in the factory of Everard and Company at Brownsfield Mills, Manchester. This was the company, wholly owned by H. V. Roe, which manufactured elastic webbing and the famous braces. Wembley Park flying ground was retained until Maj. Lindsay Lloyd converted the centre of Brooklands track into an aerodrome. 'A.V.' then returned to the scene of his 1908 experiments and made three half-mile introductory flights there on March 11, 1910. He then left for London to look after his new Roe II triplane, the first example of which, named "Mercury", was that day introduced to the public at the Olympia Aero Show.
  No doubt influenced by the success of contemporary biplanes, he later tried out this configuration using the second Roe I triplane as a guinea pig. All three outer wing panels were removed and the top two replaced by others similar to, but longer than, those of the Roe II "Mercury". At the same time a "Mercury"-type bottom centre section and improved undercarriage were fitted. The tail wheel from the original Roe I triplane was borrowed and fitted into a strengthened mounting, a piece of cannibalism which explains its absence from the Science Museum exhibit to this day. When flown in this guise at Brooklands on Easter Monday 1910, the aircraft was nicknamed the "Two-and-a-Bit Plane" but the advent of newer designs speedily ended its career and the old aircraft was dismantled at Brooklands at the end of the following month.

  Construction: By A. V. Roe at 47 West Hill, Putney, London, S.W.15; erected at Lea Marshes, Essex (1st machine) and Blackpool, Lanes. (2nd machine)
  Power Plants:
   One 9 h.p. J.A.P.
   One 20 h.p. J.A.P.
   Span 20 ft. 0 in. Length 23 ft. 0 in.
   Wing Area 285 sq. ft.
   Tailplane span 10 ft. 0 in.
   Tailplane area 35 sq. ft.
  Weights: Tare weight 300 lb. All-up weight 450 lb.
  Performance: Speed 25 m.p.h. Range 500 yards
   No. 1 Fitted with 2 cylinder 9 h.p. J.A.P., small fuel tank and tail wheel; preserved without engine or tail wheel at the Science Museum, South Kensington, London
   No. 2 Fitted with 4 cylinder 20 h.p. J.A.P., raised cylindrical fuel tank and tail skid; wings and undercarriage modified 4.10; dismantled at Brooklands 5.10

Roe II Triplane

  First product of the newly formed A. V. Roe and Company was a single seat triplane known as the Roe II. This was approximately equal in size to the original machine but was fitted with a 35 h.p. Green four cylinder, watercooled engine driving a birch two bladed, adjustable pitch airscrew. Cooling was by means of two spiral tube radiators built into, and fitting flush with, the sides of the front fuselage. The new triplane was structurally superior to its predecessors, with silver spruce struts and spars, and an ash fuselage covered with Pegamoid fabric. The undercarriage was a rigid triangulated structure to which the two-wheeled axle was secured by rubber shock absorber cord. Climbing and diving control was improved by pivoting the entire triplane tail and linking it to the mainplane variable incidence gear, the range of movement being from four to eleven degrees of incidence.
  Named "Mercury", the first Roe II triplane occupied the place of honour at a model aircraft show at White City, Manchester, on March 4, 1910 and although it had not yet flown, was priced at ?550 (with tuition). A week later it was again exhibited at the London Olympia Aero Show of March 11-19, where the Prince and Princess of Wales were shown round the machine by A. V. Roe and an order was received from W. G. Windham, later Sir Walter Windham M.P., a manufacturer of motor car bodies at Clapham Junction. References to the sale of yet another Roe II triplane to the Rangie Cycle Company appeared in several publications at the time but there is no evidence that such an aircraft was ever built.
  The exhibition machine "Mercury" was retained by A. V. Roe for school and experimental use but when flight trials began at Brooklands, it rolled on take-off and twice landed upside down. The second crash (by pupil Job), on April 17, 1910, resulted in the destruction of the undercarriage and most of the mainplanes. During reconstruction Roe took the opportunity of correcting the C.G. position by moving forward the pilot's seat, and abandoned wing warping. The control column was remounted on a universal joint, large unbalanced ailerons were hinged to the trailing edge of the top wing, and a tall rectangular rudder more than twice the area of the original was fitted. Ten days were sufficient to complete this work and "Mercury" was out again for taxying trials on April 27.
  W. G. Windham's aircraft was delivered to Brooklands early in May and assembled during Whitsun. First hops were made on May 26 by A. V. Roe who then handed it over to the owner for some preliminary taxying. The amount of flying done on this machine is uncertain but it is known that Windham landed in soft ground at Brooklands on July 12 and turned the triplane over on its back.
  Accidents to "Mercury" were now much less frequent and on Thursday June 2, Roe made several circuits of Brooklands at a height of 20 ft. and executed a number of fairly steep turns. At the end of July it was dismantled and taken to Weybridge Station along with its successor, Roe III, for dispatch by rail to the Blackpool Flying Meeting of August 1, 1910. Hopes of winning the prize money so necessary for future experiments were dashed when sparks from the engine of the L.N.W.R. goods train set fire to their truck while puffing up an incline near Wigan on July 27. Both aircraft were reduced to ashes.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey.
  Power Plant: One 35 h.p. Green
   Span 26 ft. 0 in. Length 23 ft. 0 in. Height 9 ft. 0 in.
   Wing area 280 sq. ft.
   Weight of engine without flywheel 150 lb.
   All-up weight 550 lb.
  Performance: Maximum speed 40 m.p.h.
   No. 1 "Mercury", Avro experimental, burned out near Wigan 27.7.10
   No. 2 For W. G. Windham, Brooklands
A. V. Roc at Blackpool with the first Roe I triplane in October 1909.
"Two-and-a-Bit Plane" - the second triplane with extended biplane wings, tail wheel and "Mercuiy " undercarriage at Brooklands 1910.
"Mercury" with ailerons fitted, after one of its several mishaps at Brooklands later in 1910.
In the summer of 1910 A. V. Roe and Company declared its willingness to build aeroplanes to other people's designs and the first such aircraft was a Farman-type biplane for a Bolton business man. Bolts, fittings and bracing wires were also supplied to Miss Lilian Bland who built and flew the Mayfly biplane of her own design at Carnamony, Belfast. Each of these aircraft was fitted with one of the few examples of the 20 h.p. two cylinder, horizontally opposed, aircooled Avro engines. The Farman-type evidently did not meet with much success as 18 months later, at the end of 1912, the engine and airframe were advertised for sale in new condition for ?45 and ?60 respectively.
Roe III Triplane

  The 'prototype' Roe III was a two seater, structurally similar to Roe II, but with the important difference that the mainplanes were fixed to the fuselage, climbing and diving being effected for the first time by means of a tail elevator. The aspect ratio was 8 and the bottom wing was cut back to a span of only 20 feet. The lifting tail remained, but as a result of experiments with the triplane "Mercury", lateral control was by means of ailerons (5 ft. span x 2 ft. chord), this time hinged to the rear spar of the top wing so that they were slightly inset. By this time the functions of the rudder were better understood and this organ was increased in size to a rectangle equal in height to the maximum tailplane gap as on the modified Roe II. A more robust undercarriage was of the twin-skid, four wheel Farman type and the engine a 35 h.p. J.A.P. eight cylinder Vee aircooled unit.
  First taxying trials were made at Brooklands by A. V. Roe on the evening of June 21, 1910 and the first straights were flown in a tricky wind on June 24. Flight times gradually increased until on July 4 he made a best flight of 11 minutes (with 'just a touch' after 3 1/2 minutes) and later in the day carried his mother and several other passengers. Roe seldom exceeded 20 minutes in the air in the 'prototype' Roe III because the J.A.P. engine had a tendency to overheat and cover pilot and passenger with sooty oil ejected from the scavenging holes at the base of the cylinder walls. Carburettor fires were frequent but Roe persevered until on July 9 he remained aloft for 25 minutes and made comparatively steep turns. He also practised figure eights in readiness for Royal Aero Club tests which he passed on this aircraft on July 20. Aviator's Certificate No. 18 was issued to the great pioneer on July 26, but within a year he had given up piloting in favour of designing and did not take the Air Ministry's 'A' Licence tests when they came into being in 1919. He kept no log books and did not know how many hours he had flown as pilot. The J.A.P. engined Roe III was advertised secondhand by the makers for ?250 in May 1911 but its ultimate fate is uncertain.
  The three subsequent triplanes of this type (all powered by 35 h.p. Green four cylinder, watercooled engines) had the span of the top mainplane increased to 31 ft. and were fitted with ailerons hinged to the rear spar of the centre wing. First of these, identified by rounded corners to the trailing edge of the rudder and by fuselage covering applied only in the region of the cockpits, was a special slow flying aircraft with a more heavily cambered wing section for instructional use at the Avro School. Piloted by the designer, this triplane first flew at Brooklands on July 9, 1910 and its performance was at once encouraging. Both Roe and Pixton carried passengers on July 13 and one another on the following day. At the end of the month the machine was sent by train from Weybridge to the Blackpool meeting only to destroyed by fire en route together with the Roe II "Mercury".
  Determined to compete, Roe and Pixton hastily brought spare components from the Manchester works to Blackpool and arranged for a new engine to be delivered direct from the Green factory. Work started on Thursday July 28 and the finished aircraft flew on Monday August 1, much of the erection having been done by Roe himself during the previous night. There was not even time to cover the fuselage. Three attempts were made to take off, during which a tyre burst and some rubber shock absorbers snapped. Two struts were broken on landing but not before Roe had made four circuits of the course, at least two with passengers (who could face forward or backward according to taste). For this he received a special merit award of ? 50. August 2 dawned wet and windy but after repairs Roe succeeded in making two more short hops at 7.30 p.m. and on the following afternoon left the ground in a much more lively manner. In turning, the wind carried him dangerously close to one of the pylons, to avoid which he had no alternative but to make a crash landing, breaking several more struts, the airscrew and one mainplane.
  Visitors to the Blackpool meeting included J. V. Martin, organiser of the Harvard University Aeronautical Society, who ordered a Roe III triplane which was built, crated and despatched (without engine) to the U.S.A. by August 13! A. V. Roe and Claude Grahame-White were also invited to fly at the Boston Aviation Meeting scheduled to open on September 2. They left in the White Star liner Cymric on August 23, Roe taking with him the makeshift Blackpool triplane in a 40 ft. packing case. Arriving at Boston on September 1, they collected the Harvard Society's triplane (which had been stored at East Boston Docks since its arrival in the Cunarder Ivernia a week previously), and took all the aircraft by lighter to the airfield at Squantum Point. Here Roe and mechanics Pixton and Halstead completed the erection of the Blackpool triplane on September 3, but flights begun on September 6 were disappointing, the longest being 75 ft. at a height of 10 ft. At 5 p.m. the engine failed and the triplane landed heavily in front of the grandstand, damaging the starboard mainplanes and undercarriage. Local woodworker C. H. Metz made a new airscrew and at 6.30 p.m. on September 8 Roe succeeded in leaving the ground properly for the first time, reaching a height of 30 feet. When he shut off the engine to land, however, a sudden gust caused the aircraft to swerve to starboard and dig the right undercarriage skid into the ground, causing it to swing round with major breakages. Roe was unhurt and more determined than ever to show the Americans that his triplanes were more than just interesting freaks. On September 9 he secured permission from Harvard to erect the Society's triplane and fit it with the 35 h.p. Green engine taken from the wreck. Erection was completed and engine runs made on September 12 and it is said that the aircraft was slightly heavier than its predecessor and had two instead of four wheels. Two days later, amid the applause of 10,000 spectators, successful flights were made up to a height of 50 feet but the engine still refused to give full power. After tinkering with it for most of September 15, Roe made a good take-off at 4.20 p.m. and flew the length of the field. In attempting to round the pylon, he sideslipped into the ground from 50 feet, totally wrecking the port side of the aircraft and suffering a severe scalp wound. A cordon of police saved the wreck from souvenir hunters and after A. V. Roe returned to England, Pixton built a new triplane for Harvard out of the remains of the other two. He then sold the surplus spares to the local aircraft firm of Burgess and Co. and Curtiss of Marblehead to raise money for his passage home, leaving Harvard with their machine untested in the air.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plants:
   One 35 h.p. J.A.P.
   One 35 h.p. Green
   Span (upper) 31 ft. 0 in. (lower) 20 ft. 0 in.
   Length 23 ft. 0 in. Wing area 287 sq. ft.
   Tailplane area 75 sq. ft.
  Weight: All-up weight 750 lb.
   No. 1 Prototype with 35 h.p. J.A.P., first flown 24.6.10, up for sale 5.11
   No. 2 Avro School machine, first flown 9.7.10, burned out 27.7.10
   No. 3 Blackpool makeshift machine, first flown 1.8.10, crashed at Boston, U.S.A. 8.9.10
   No. 4 Harvard Aeronautical Society machine, first flown (and crashed) at Boston, U.S.A. 15.9.10

  Note: A work of reference of the period states that a triplane of this type was built for the great pioneer pilot Cecil Grace. This aircraft is conspicuous by its absence from contemporary records and diligent research by the author only makes it evident that no such aircraft existed.
The Roe III triplane (35 h.p. J.A.P.) in flight with ailerons fitted to the top wing.
Roe IV Triplane

  The last of A. V. Roe's primitive triplanes, completed in September 1910, was a single seater structurally similar to its predecessors and powered by a 35 h.p. Green watercooled engine, the radiator for which was mounted in the centre section gap. The shortened bottom wing was retained but the wing chord was somewhat reduced. Despite the improved lateral control given by ailerons, the Roe IV Triplane reverted to wing warping, effected by rotating a control wheel mounted on a column which moved fore and aft for diving and climbing. The tailplane was triangular in shape and for the first time of the non-lifting monoplane type equipped with movable elevators. The familiar four wheeled undercarriage of the previous triplanes was also a feature of Roe IV.
  By the middle of 1910 'A.V.' was fast becoming interested in building a biplane, with the result that only one Roe IV was constructed. It was used almost exclusively for instructional work at the Avro Flying School at Brooklands where pupils found it rather sensitive on the controls and more difficult to master than the earlier machines. Needless to say it was broken many times as on October 10, 1910 when, in the words of an onlooker, "a pupil rose unsteadily and after 225 yards slowly sideslipped into the sewage farm, completely smashing the starboard mainplane." Such incidents were so frequent that they excited little comment and the aircraft structure was so simple that even major damage could often be put right the same day.
  Several famous pilots were trained on the Roe IV triplane, including Hubert Oxley and C. Howard Pixton, the former starting his training with a flourish by attempting to take off down wind without previous experience and nosing over in the sewage farm on October 17, 1910. Pixton, practising figure eights at 200 ft. on November 8 for his Royal Aero Club certificate, sideslipped Roe IV into the ground, where it caught fire and suffered extensive damage. Nevertheless the machine was out again on November 17, back in the sewage farm by December 4 and carried Pixton successfully through the tests for his aviator's certificate on January 24, 1911. It continued to suffer at the hands of trainees such as F. Conway Jenkins, Gordon Bell, R. C. Kemp and Lt. W. D. Beatty, until the last mentioned slipped in and badly wrecked it on February 14, 1911. This time the damage took a fortnight to repair and the opportunity was taken to insert a four foot extension piece into the fuselage.
  Pixton made the first test flight in the revised Roe IV on March 1 and managed to coax it up to 750 ft. This performance contrasted sharply with the usual 150 ft. ceiling associated with this machine. A week later on March 8, engine trouble compelled R. C. Kemp to abandon the tests for his certificate and soon afterwards (certainly no later than August 1911) the Roe IV was dismantled and replaced at the Avro School by the Type D biplane of superior performance.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plant: One 35 h.p. Green
   Span (upper) 32 ft. 0 in. (bottom) 20 ft. 0 in.
   Length 30 ft. 0 in. (increased to 34 ft. 0 in. February 1911)
   Height 9 ft. 0 in. Wing area 294 sq. ft.
  Weights: Airframe less engine 350 lb. All-up weight 650 lb.
  Production: One aircraft only, completed 9.10, withdrawn from use at Brooklands about 8.11
Avro Type D

  In 1911 A. V. Roe abandoned the triplane configuration and designed a biplane which bore a close resemblance to the Roe IV. It was a two seater with triangular girder fuselage, twin undercarriage and the same type of cumbersome, triangular monoplane tail. This was replaced almost at once by one of rectangular shape. As on Roe IV, lateral control was by means of wing warping but the passenger seat was placed at the C.G. so that the machine could be flown solo without ballast. Power was supplied by a 35 h.p. Green, the radiator for which, placed vertically behind the engine at right angles to the direction of flight, distinguished this machine from later aircraft of the same type. It is probable that the engine was that knocked down to A. V. Roe for ?67 10s. when the assets of the Scottish Aviation Syndicate were auctioned at Brooklands on December 17, 1910.
  In later years aircraft of this type became known as the Avro Type D even though no reference seems to have been made to Types A, B, or C. These, of course, would have been designations posthumously applied to the early triplanes.
  The first Avro Type D was erected at Brooklands in March 1911 and first flown on April 1 by C. Howard Pixton (who later took Mrs. Roe up in it). He declared it stable, viceless and easy to fly, characteristics confirmed by Gordon Bell and effectively demonstrated on April 11 by Lt. Wilfred Parke R.N. who, without having been in an aeroplane before, flew the length of the aerodrome. Numbered 1, it was flown in the Brooklands-Shoreham race by Pixton on May 6, 1911 - the first event in which the Avro entry was not flown by the designer. Pixton lost time at the start because he was flying round in an attempt to win the ?500 Manville endurance prize with passenger. He had completed 26 minutes 30 seconds before noticing competitors taking off at the start of the race. He had no map, no cross country experience, and the Type D had never before been flown outside Brooklands Aerodrome. Nevertheless he made a hasty landing to refuel and set off after the others. He lost his way and took three hours for the trip, landing en route at Plumpton Racecourse, seven miles short of his destination. On the way back he spent two days at a flying demonstration at Oakwood, Haywards Heath, returning to Brooklands on Monday May 9 after a very turbulent trip via Dorking. On May 12 he flew the Type D to Hendon in 48 minutes to give a flying display before the Parliamentary Aerial Defence Committee, during which he carried the famous Cdr. Sampson R.N. as passenger and sent A. V. Roe solo in the machine for the first time. Pixton flew home to Brooklands next day and on May 19 made a nonstop flight of 1 hour 30 minutes towards the Manville prize. On June 11 the Type D climbed to a considerable height with the 12 stone Pixton and a 14 stone passenger.
  After a flight at Brooklands in June 1911, Cdr. Schwann (later A.V.M. Sir Oliver Schwann K.C.B., C.B.E.) of the Naval Airship Tender Hermione, bought the Type D for ?700. It was despatched by rail to Barrow-in-Furness where the original triangular tailplane was replaced, the wheels removed and the skids lashed directly to a series of float undercarriages designed by Schwann and his associates and built by naval personnel. The drag of the floats was partially offset by repositioning the radiator horizontally on top of the centre section and by covering the rear fuselage with fabric.
  During first taxying trials on August 2 in the 9 ft. deep Cavendish Dock on Schwann's narrow, flat bottomed Mk. I floats, the aircraft assumed such a tail-down attitude on the water that the small tail float caused excessive wash. This and the fin were therefore removed and the rudder moved upward along the hinge line to clear the water. Later the rudder was raised still further till the lower edge was in line with the bottom of the fuselage. Maximum speed was only 18 knots and the machine eventually capsized. Report R. & M. 69 deals at length with Schwann's further experiments with seven different types of single and twin float undercarriages. Limited success came on November 18, 1911 after the Green Engine Co. Ltd. had coaxed an extra 10 h.p. out of the engine by fitting additional open exhaust ports, and float design had reached the Mk. VII stepped type. On that day the Type D lifted on to the step for the first time and left the water rather unexpectedly, reaching a height of 15-20 ft. Schwann was not at that time a qualified pilot and the aircraft fell back into the water and capsized. After salvage and reconstruction, trials were resumed by S. V. Sippe who made the first of a series of short flights at Barrow on April 9, 1912 during which he reported favourably on the feeling of acceleration from the unstick speed of 25 m.p.h. to the flying speed of 40 m.p.h. It became the first seaplane ever to take off from British sea water. On April 12 Sippe made two or three circuits of the dock and reached a height of 160 feet. The seaplane was then handed over to the owner who had just qualified as a pilot at the Bristol School on Salisbury Plain. The feasibility of marine aircraft had been proved but the rate of climb of the Type D seaplane was poor due to an increase in all-up weight to 1,000 lb. (an accurate figure obtained by weighing the machine in the airship shed at Barrow). Endurance was but 20 minutes - the time taken for the cooling water to boil away, so a 50 h.p. Gnome rotary was fitted in an attempt to improve the performance, but there are no recorded flights with this engine.
  The sale of the Type D biplane reduced the Avro School to only one aircraft - the Roe IV triplane. Pending delivery of new machines from Manchester, A. V. Roe acquired a secondhand Gnome-engined Farman pusher purchased in Newcastle. The crates housing this relic were too big for railway trucks and travelled south by sea at a cost of ?25. This charge contrasted sharply with that for Avro aircraft, which broke down into sections to fit into a single crate, the Manchester-Brooklands rail charge for which was a mere ?1 16s. 6d.
  The next Avro aircraft was a modified Type D built to compete in the ?10,000 Daily Mail Circuit of Britain Race. It was a sesquiplane with upper and lower spans of 33 and 23 feet, powered by a 60 h.p. E.N.V. eight cylinder, watercooled engine. Like all subsequent machines of the type, its fuselage was increased in length from 26 ft. to 28 ft., but it was the only one, apart from the prototype, to be fitted with the large triangular tailplane. Construction took place at Manchester during June 1911 under the watchful eye of the pilot, R. C. Kemp, and first taxying trials were made at Brooklands by A. V. Roe on July 18. First flights made by Kemp later in the day showed the machine to be fast, but the engine overheated and the rate of climb was poor with full load of petrol and oil. Without A. V. Roe's approval, extensions were hurriedly fitted to the lower wing, making it equal in span to the upper and increasing the wing area by 50 sq. ft. After an initial test circuit at 100 ft. on July 22, morning of the race, Kemp climbed to 800 ft. but during a fairly steep descent at half throttle the extension to the port lower mainplane failed at 150 ft. Although he jerked on full right rudder and full left warp, the machine spun into the ground wingtip first and broke up. Miraculously Kemp stepped unhurt from the wreckage.
  The third Type D, the assembly of which was completed at Brooklands on September 9, 1911, was almost identical with the first but distinguishable from it because drag had been reduced by fitting the radiator in a sloping position behind the engine. Minor differences included straighter front skids, a covered fuselage and no fin. First straight hops were made by F. P. Raynham on September 11 and after adjustments a flight to 600 ft. was made on September 17. Although intended as a school machine, it was entered for the Michelin Speed Prize but during his flight to Hendon to compete on September 21, Raynham ran into thick fog. In attempting to 'press on' with primitive instruments, he made what may have been the first recorded spin and recovery, afterwards landing at New Barnet to ask his way. Unsatisfactory experiments with a new airscrew, and sagging wing fabric compelled him to give up the attempt. He therefore returned to base, arriving over Brooklands at 1,000 ft. on the evening of September 24 and by the end of the month the Type D was in full time use by the Avro School.
  Delivered at Brooklands on September 30, 1911, the fourth Type D was a single seater but otherwise identical with the equal span school version, except for the radiator which was fitted vertically behind the engine in line with the direction of flight. The engine was a specially tuned Green giving 45 h.p. and identified by holes at the base of the cylinder walls which improved scavenging. After some trouble with slack fabric, satisfactory first flights on October 12 again raised Raynham's Michelin hopes and although he reached 1,000 ft. with 5 hours' fuel (13 gallons) during a practice flight two days later, bad weather on October 15, last day of the competition, ruined his chances. With an eye on the Michelin long distance prize, he coaxed the machine off on October 18 with 8 hours' fuel (24 gallons) but the attempt came to an abrupt end when the machine forced landed in the sewage farm with an iced-up carburettor on October 27, only three days before the closing date.
  The fifth Type D was an improved sesquiplane version generally similar to, and having the same dimensions as, the ill-fated Circuit of Britain machine. The engine was a 35 h.p. Green.
  The sixth machine was a single seater powered by a new 35 h.p. five cylinder Viale aircooled radial which had been delivered to A. V. Roe on September 30, 1911. The installation was done by Maurice Ducrocq (British concessionaire for Viale engines) and his apprentice Jack Alcock. Work was completed on October 6 but it was not until November 20 that first nights were made by F. P. Raynham. The Viale-powered Type D proved very manoeuvrable and flew strongly in the hands of a number of school pilots. On December 6 Raynham used it for joyriding by removing the fuselage petrol tank to make room for a passenger to kneel facing him. On December 27 Wilfred Parke climbed the machine to 2,500 ft. over Addlestonc as a prelude to his 'Superior Brevet' tests and S. V. Sippe gained his Aviator's Certificate on it on January 8, 1912. During at attempt to fly to Oxford as part of his tests on January 13, Parke followed the Thames until poor visibility forced him down at Abingdon where he broke two bracing wires. On the following morning the machine was dismantled in 65 minutes and temporarily stored in a local garage. No later flights by this machine are recorded and its Viale engine was installed in the Avro Type F cabin monoplane in the following April.
  The precise number of Type D biplanes produced by the Manchester works was never made known. None was built after 1912 and advertisements making a special offer of 12 Type Ds at a reduced price of ?400 each during October and November 1911 can only be regarded as a publicity stunt. There is no evidence that any orders were placed.
  In October 1912 the Avro School moved from Brooklands to the new aerodrome at Shoreham-by-Sea, Sussex, and became the Avro Flying School (Brighton) Ltd. with A. E. Geere as C.F.I. Last noteworthy nights before the transfer were made in mid-August by Wilfred Parke in the old sloping radiator Type D to Staines, Ripley, Hounslow Heath and Walton. The machine was used for instruction at Shoreham during 1913 and became well known along the South Coast as did the school's 45 h.p. Green engined Type D, Type D with 50 h.p. Isaacson seven cylinder radial, and the Avro Type E prototype described later.
  It is unlikely that the sixth Type D, undamaged in the Abingdon forced landing, would have been scrapped after the removal of the Viale engine. It seems more probable that its front fuselage, already modified for radial engines, invited the installation of a more powerful unit. In the absence of definite proof it can reasonably be assumed that this was the Isaacson machine.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; Brooklands Aerodrome, Surrey; and Shoreham Aerodrome, Sussex
  Power Plants:
   One 35 h.p. Green
   One 45 h.p. Green
   One 35 h.p. Viale
   One 50 h.p. Isaacson
   One 60 h.p. E.N.V. Type F
  Dimensions, Weights and Performances:
   Standard Seaplane Sesquiplane
  Span, upper 31 ft. 0 in. 31 ft. 0 in. 33 ft. 0 in.
  Span, lower 31 ft. 0 in. 31 ft. 0 in. 23 ft. 0 in.
  Length 28 ft. 0 in.(*) 26 ft. 0 in. 28 ft. 0 in.
  Height 9 ft. 2 in. - 9 ft. 2 in.
  Wing area 310 sq. ft. 310 sq. ft. 279 sq. ft.
  All-up weight 500 lb. 1,000 lb. 550 lb.
  Speed 45-50 m.p.h. 40 m.p.h. -
  Range 100 miles(**) - -
   (o)Prototype 26 ft. 0 in. (**)With Viale engine.

   No. 1 Prototype, 35 h.p. Green, transverse radiator, first flown 1.4.11, converted to seaplane, last mentioned 4.12;
   No. 2 Circuit of Britain machine, E.N.V. engine, first flown 18.7.11, crashed at Brooklands 22.7.11;
   No. 3 School machine, 35 h.p. Green, slanting radiator, first flown 11.9.11, withdrawn from use at Shoreham 5.14;
   No. 4 Single seater, 45 h.p. Green, fore-and-aft radiator, first flown 12.10.11, withdrawn from use at Shoreham 5.14;
   No. 5 Improved sesquiplane, believed that advertised for sale at Shed 4, Brooklands, 5.12 and that reported scrapped near the petrol store 12.12;
   No. 6 School machine, Viale engine, first flown 20.11.11, almost certainly re-engined with 50 h.p. Isaacson, withdrawn from use at Shoreham 5.14
The original Avro Type D biplane with transverse radiator.
The special Type D with E.N.V. engine at Brooklands on the eve of the Circuit of Britain Race, July 1911.
The fifth Type D was the improved sesquiplane version.
The Burga Monoplane

  In 1912 A. V. Roe and Company built a shoulder-wing monoplane to the designs of Lt. Burga of the Peruvian Navy, who wished to try out some highly original ideas on aircraft control. The machine was constructed at Brownsfield Mills at the same time as the Avro Type E prototype and used the same tail and undercarriage, but the fuselage was much slimmer and the engine a 50 h.p. Gnome rotary. It is probable that the Burga monoplane was, in fact, the Avro 502 of which no details survive except that it was a single seat monoplane.
  Rectangular monoplane wings were wire braced to strong points on the undercarriage and to a pylon built above the fuselage. There was no wing warping, lateral control being obtained by two 'rudders', one above and one below the fuselage, working in opposite directions. The design made provisions for wings of varying camber which fitted at varying angles of incidence to give the machine any desired performance.
  Lt. Burga took a shed at Shoreham where the machine was test flown on November 20, 1912 by H. R. Simms. The mainplanes fitted were those best suited for maximum speed and the pilot reported that it was certainly fast and had a good rate of climb. Further taxying trials were made by H. S. Powell in the following month, and in January 1913 the Burga monoplane returned to the Avro works at Manchester for modification.

  Manufacturers: A. V. Roc and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Shoreham Aerodrome, Sussex
  Power Plant: One 50 h.p. Gnome
  Dimensions: Length 29 ft. 0 in.
  Production: One aircraft only, first flown at Shoreham 20.11.12
The Duigan Biplane

  John R. Duigan was an Australian who designed and built a Farman-type biplane at Mia Mia, Victoria in 1910 and flew it before a very large crowd at Bendigo Racecourse, Melbourne on May 3, 1911. A series of accidents convinced Duigan that he needed proper flying instruction and later in the year he sailed for England, arriving in October 1911. He went at once to Brooklands, joined the Avro School, placed an order for a private Avro aeroplane and in the following month went off to Manchester to see it built.
  The machine was a two seat, dual control biplane, similar to Type D but fitted with a square rudder, steel framed tailplane and square instead of triangular section fuselage. The seats were arranged so that the occupants' heads were raised just above the padded rim of an elliptical opening and celluloid windows were provided in the floor to give downward view. Following current Continental practice, Roe tried a newer wing section having 'Phillips entry' whereby the chord line of the wing was horizontal in level flight. Wing warping was employed for lateral control and wing spars were of English ash with poplar ribs, rounded wingtips being formed from rattan cane. As usual, the whole machine was built in sections, easily dismantled for transport, the fuselage consisting of two halves bolted together behind the rear cockpit. The engine was a 40 h.p. horizontally opposed Alvaston driving an Avro airscrew of Kauri pine and cooled by large spiral tube radiators on each side of the front cockpit.
  The undercarriage was a complete departure from normal Avro practice, incorporating a Nieuport-type leaf-spring axle and centre skid with bracing wires to flatten long grass and prevent nosing over. This type of undercarriage proved so successful that in modified form it was used on Avro aeroplanes for a generation.
  First straight hops were made by Duigan at Huntingdon Racecourse flying ground early in February 1912 but in spite of experiments with different airscrews the machine was very loath to leave terra firma. Considering it advisable to return to the Avro fold, Duigan took the machine to Brooklands where a 35 h.p. E.N.V. engine was fitted and he met with more success. On March 10 several long straight flights were made but the aircraft was sadly underpowered and only flyable in good weather. Duigan then made and fitted an airscrew of his own design and working as his own mechanic, tuned the E.N.V. engine to such good effect that on April 12 he succeeded in flying several times round Brooklands track. On April 19 he flew figure eights at 300 ft. and on April 27 successfully completed tests for his Aviator's Certificate, the aircraft having completed four hours in the air up to that date entirely without damage. Passenger flights, not so successful on low power, were confined to straights within Brooklands track. Duigan's best and final solo flight in his machine, consisting of an hour's circuits over Addlestone at an altitude of 400-600 ft., was made on April 30.
  Having achieved his objectives, Duigan returned home. There he built a very similar machine to the Avro which crashed on its first flight on February 17, 1913. His British aeroplane was put up for sale with engine for ?380 but was almost immediately reduced to ?180, no doubt because the engine had been sold separately. The airframe was purchased by the Lakes Flying Company who rebuilt it at Windermere as the centre float seaplane Sea Bird which H. Stanley-Adams flew off the lake for the first time on August 28, 1912. The company entirely redesigned the front end of the fuselage to accept a 50 h.p. Gnome rotary, the upper half of which was cowled and gave a cocked-up appearance to the nose. New three bay, warping mainplanes of Eiffel 12 section and 8-5 aspect ratio were also fitted. The machine proved much faster than the old Avro-built Water Bird and after it had been fitted with an improved twin float undercarriage, carried large numbers of holidaymakers during 1912-13. Dual control was fitted in 1915 but Sea Bird was destroyed in June of that year when pupil R. Buck spun in from 300 ft.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey. Rebuilt by The Lakes Flying Company, Cockshott, Lake Windermere, Westmorland
  Power Plants:
   One 40 h.p. Alvaston
   One 35 h.p. E.N.V. Type D
   (Sea Bird) One 50 h.p. Gnome
   (Duigan) Span 34 ft. 0 in. Chord 4 ft. 6 in.
   (Sea Bird) Span 39 ft. 4 in. Length 29 ft. 4 in.
   Height 10 ft. 6 in. Wing area 350 sq. ft.
   (Duigan) Speed 40 m.p.h.
   (Sea Bird) Maximum speed 62 m.p.h.

  Production: One aircraft only, first flown 2.12; converted into the Lakes Sea Bird 10.12, crashed at Windermere 6.15

Avro 500 (Type E)

  The first War Office military aircraft specification, issued in 1911, called for a two seater to carry a 350 lb. load in addition to essential equipment and have an endurance of 4 1/2 hours, initial rate of climb of 200 ft./min., maximum speed 55 m.p.h., ability to maintain 4,500 ft. for one hour, and be capable of delivery to Salisbury Plain in a crate. Competing firms had only nine months in which to design, build and test.
  A. V. Roe and Company met this specification by building a new two-seat biplane, very similar in design and construction to the previous year's Duigan machine. The built-up box-girder fuselage was again of square section, fabric covered in the rear and metal clad forward. It was more streamlined than the Duigan with pilot and passenger seated at the widest part with their heads protruding through padded openings in the top. Small celluloid panels were again provided in the floor to give downward vision. The mainplanes used ash spars and an improved, double-surfaced section covered with Pegamoid fabric. They were detachable in three sections for ground transport. The undercarriage was of the Duigan type with centre skid and leaf-spring axle, the tail being carried on a rubber-sprung skid.
  A 60 h.p. E.N.V. watercooled engine was mounted on the top longerons and drove a 10 ft. Avro airscrew. The main fuel tank was in front of the passenger and twin gravity tanks were fixed to the centre section struts. Known originally as the 'Military Biplane', but in later years as the Type E prototype, the machine was first flown at Brooklands by Wilfred Parke on March 3,1912. It was obvious from the outset that this was no ordinary aircraft but one with that rare quality, a reserve of power. This encouraged its entry for the Mortimer Singer prize. Test flying took but a few days, during which it was promptly dubbed "Elinor Glyn" (after a well-known novelist of the period) and on March 23 Parke climbed to 1,000 ft. in under six minutes and to 2,000 ft. in 13 minutes with a heavy passenger (R. L. Charteris).
  Cooling was by spiral tube radiators on each side of the front fuselage, augmented by two smaller units on the centre section struts on each side of the passenger's head. On April 20 Parke suffered partial engine failure when taking off for Hendon to compete for the prize. The hurried landing ripped off undercarriage and mainplanes and when the aircraft rolled on its side the auxiliary radiators folded over the front cockpit and engineer W. H. Sayers had to be extricated through a hole cut in the side. In the interest of future passengers the machine was rebuilt with only the lower radiators fitted. Parke successfully piloted the machine through Farnborough trials in June 1912 after which it returned to Brooklands to become a flying testbed for the new 60 h.p. A.B.C. engine. First straight hops with this power unit were made by F. P. Raynham on August 31 but it was not until October 18, when several engine and airframe adjustments had been made, that it flew strongly in the hands of the A.B.C. representative R. L. Charteris. In 1913 the E.N.V. engine was reinstalled and the aircraft sent to Shoreham and there flown by experienced pilots of the Avro School, such as H. R. Simms and H. S. Powell. On June 29, 1913 pupils were allowed to fly it for the first time but in the afternoon it stalled on a turn, crashed and was destroyed by fire. Pilot R. N. Wight received fatal injuries, the first ever in an Avro aircraft.

  Manufacturers: A. V. Roe and Company (reconstituted as A. V. Roe and Co. Ltd., 11.1.13), Brownsfield Mills, Great Ancoats Street, Manchester (moved to Clifton Street, Miles Platting, Manchester, 4.13); and at Shoreham Aerodrome, Sussex
  Power Plants:
   (Type E prototype) One 60 h.p. E.N.V. Type F
   One 60 h.p. A.B.C.
   Span 36 ft. 0 in. Height 9 ft. 9 in.
   (Type E prototype) 30 ft. 6 in.
   Wing area 330 sq. ft.
   (Type E prototype) Tare weight 1,100 lb. All-up weight 1,650 lb.
   (Type E prototype)
   Maximum speed 50 m.p.h.
   Initial climb 170 ft./min. Endurance 6 hours

   Type E
   Prototype only, first flown at Brooklands 3.3.12, destroyed by fire at Shoreham 29.6.13
J. R. Duigan flying the biplane with 35 h.p. E.N.V. engine at Brooklands April 1912.
Avro 500 (Type E)

   Although he had created a remarkable aeroplane, A. V. Roe was not altogether satisfied. He therefore built an almost identical machine and fitted the 50 h.p. Gnome seven cylinder rotary taken from the superannuated Avro School Farman when it was dismantled in November 1911. The Gnome, only a fraction of the weight of other engines of similar power, gave the machine a much enhanced performance and during first flights at Brooklands by Parke on May 8, 1912 the machine reached 2,000 ft. in five minutes. The next day he flew 17 miles to Laffan's Plain in 20 minutes and completed all official trials the same afternoon. Officialdom was impressed and after some haggling over price, the War Office bought it and ordered two others with dual control. One of these is said to have been tested to destruction under ground load, but recent researches make it clear that the Avro 500 in question was merely proof loaded as part of the acceptance trials.
   A. V. Roe always regarded the Gnome powered Type E as his first really successful aeroplane. Dismissing all previous machines as mere experiments he gave it the imposing type number 500, first of the Avro series which continues in use until the present day.
   Wilfred Parke first flew the second Avro 500 at Brooklands on June 5, 1912 and delivered it to Farnborough in 23 minutes later in the day. Although so many Avro aircraft had first seen the light of day in Manchester, the inhabitants of that city had not at that time seen one in the air. To remedy this the third Army machine was 'borrowed' on June 28, taken from the factory to Eccles Cricket Ground and next day flown over Chorlton by Parke. Flights were made from Old Trafford over the Docks on the following day and from Fallowfield on July 5. After minor repairs the machine was then flown to Brooklands for normal flight test by Parke (with Gordon Bell as passenger) on July 19 before delivery by Raynham on July 22. The three Avro 500s joined the strength of the Central Flying School, Upavon, with serial numbers 404, 405 and 406. They were flown by pilots who later became famous, such as Maj. Brooke-Popham (later Air Chief Marshal Sir Robert Brooke-Popham, Governor of Kenya) and Lt.-Col. Cook R.A. who made a notable flight to Portsmouth in 404 on August 8, returning via Lee-on-Solent (50 miles) in 40 minutes on August 17. The Avro 500 rapidly established itself as the best available trainer, resulting in a further order for four two seaters in November 1912 and another for five single seaters to equip No. 3 Squadron, Netheravon, in January 1913.
   Years of endeavour were being rewarded. To A. V. Roe fell the honour of escorting H.M. King George V round the second machine of the two seater batch at the Olympia Aero Show of February 14-22, 1913. With total orders at the dozen mark the firm had become sufficiently stable financially to re-form as a limited company on January 11, 1913 and to move into larger premises at Clifton Street, Miles Platting, Manchester in the following April. War Office orders were completed in June 1913 (the penultimate single seater was tested at Shoreham by F. P. Raynham on June 12) and later in the year six others were supplied to the Air Department of the Admiralty. These were stationed at Eastchurch, where the first, 41, was commissioned in August and the second, 51, passed its one hour acceptance tests on September 25, 1913. The pilot was Raynham with Lt. J. W. Seddon, Inspector of Naval Aircraft, as passenger. Deliveries ended with 750 in April 1914.
   During the short Service life of the Avro 500, several important modifications were made. The prototype had no tail skid and depended on a steel shoe screwed to the bottom of the rudder. It was a weak arrangement and the rudder was redesigned to absorb landing shocks by sliding vertically up the kingpost against the action of a coiled spring. By mid-1913 this still somewhat hazardous system had been abandoned in favour of an ordinary bungee-sprung tail skid and the now-famous comma-shaped Avro rudder. Lateral control on all War Office single and two seat Avro 500s was by wing warping but modified outer wing panels incorporating inversely tapered ailerons on top and bottom wings were fitted later. At least 406 was further modified with constant chord ailerons, while in several instances the looped wing tip skids were replaced by braced bamboo rods with, or without, a small wheel at the tip.
   A few Avro 500s remained in commission throughout the early years of the First World War and one was locally re-engined at Chingford with a 100 h.p. Gnome 14 cylinder rotary.
   There were at least three other Avro 500s in addition to War Office and Admiralty machines. The first, of the sprung rudder type, was built for the Portuguese Government and paid for by public subscription. Despatched to Lisbon in September 1912 in charge of H. V. Roe, Copland Perry (pilot) and W. H. Sayers (engineer), it was unloaded on October 7 and conveyed by bullock cart to the flying ground at Belem. It was erected and flown on successive days, after which trial flights were made up the Tagus to Lisbon with the name "Republica" in large red letters on the fuselage and in green under the mainplanes. The machine was handed over to the Minister of War before 20,000 people on October 16 but the next day Perry just failed to reach the aerodrome when an exhaust valve on the Gnome jammed open. He put the Avro down gently in shallow water from which it was salvaged without damage, cleaned down, greased and stored for the winter.
   The best known of all Avro 500s was probably that flown by F. P. Raynham to the Burton-on-Trent Meeting of August 2-5,1913 during which he carried numerous passengers and won the quick starting and cross country races. As if to underline the fact that this was no 'stick and string' freak, Raynham flew the machine south to Brooklands after the meeting and on August 9 raced it from scratch into second place in the six laps speed race at the Hendon August Meeting. Raynham then became so fully engaged in demonstrating the new Avro 504 prototype that the faithful 500 languished at Brooklands until he was free to give dual instruction to H. V. Roe and C. F. Lan-Davis. The latter bought the machine in December 1913 and gained his Aviator's Certificate on it on March 24, 1914. He first kept the machine at Brooklands but it was later based at Hendon where Lan-Davis fitted an elaborate array of instruments. He also attempted to mass balance the elevator by fitting broomsticks which projected forward at each end.
   The other 'civil' Avro 500, delivered Brooklands-Hendon by F. P. Raynham on January 22, 1914 was used for display and instruction by J. Laurence Hall whose name appeared large on the fuselage. Two months later Hall succeeded in looping the machine to show that standard British aircraft were quite as manoeuvrable as the special lightweight French machines of the period. He flew hundreds of trouble-free hours in it and made numerous cross country flights including a 45 minute trip from Shoreham to Hendon with a lady passenger on July 14. An order for four Avro 500s by the Royal Aero Club was frustrated by the outbreak of the First World War but the Hall machine continued in instructional use at Hendon until commandeered by the War Office in September 1914. It remained in the same employ but carried serial 939 and in common with other surviving Avro 500s, was fitted with a twin skid undercarriage and oversize wheels.

   Manufacturers: A. V. Roe and Company (reconstituted as A. V. Roe and Co. Ltd., 11.1.13), Brownsfield Mills, Great Ancoats Street, Manchester (moved to Clifton Street, Miles Platting, Manchester, 4.13); and at Shoreham Aerodrome, Sussex
   Power Plants:
   (Avro 500) One 50 h.p. Gnome
   One 100 h.p. Gnome
   Span 36 ft. 0 in. Height 9 ft. 9 in.
   (Avro 500) 29 ft. 0 in.
   Wing area 330 sq. ft.
   (Avro 500) Tare weight 900 lb. All-up weight 1,300 lb.
   (Avro 500)
   Maximum speed 61 m.p.h.
   Initial climb 440 ft./min.

   Avro 500
   Two seaters to War Office Contract May 1912 : 404 and 405 first flown at Brooklands 8.5.12 and 5.6.12 respectively, delivered to Farnborough 9.5.12 and 5.6.12, thence to C.F.S., Upavon; 406 first flown at Manchester 28.6.12, to Farnborough 22.7.12, thence to C.F.S., Upavon.
   Two seaters to War Office Contract December 1912 : 430, 432, 433 and 448 to C.F.S., Upavon.
   Single seaters to War Office Contract January 1913: 285 and 288-291 to No. 3 Squadron, Netheravon 1913, to Farnborough 1914.
   Two seaters to Admiralty Contract 1913: 41 delivered to Eastchurch 8.13, crashed at Eastchurch 7.3.14; 51 to Eastchurch 25.9.13, later to Hendon, written off 11.8.15; 52 to Eastchurch 10.14, to Hendon 12.14, at Chingford 1916 with 100 h.p. Gnome; 53 at Eastchurch 1916; 94 no information; 150 to Eastchurch 4.14.
   Other two seaters:
   1. For the Portuguese Government, delivered at Lisbon 16.10.12
   2. Demonstrator, first flown 7.13, sold to C. F. Lan-Davis 12.13, awaiting more powerful engine at Hendon 8.14 3. To J. L. Hall, Hendon 22.1.14, commandeered 9.14 and allotted R.F.C. serial 939
J. Laurence Hall in the 'civil' Avro 500 at Hendon in January 1914. Typical of late production 500s it had the 'comma' rudder and inversely tapered ailerons.
The Avro 500 prototype with 50 h.p. Gnome rotary engine and the original sprung rudder.
The Hall School's Avro 500 at Hendon late in 1914 on war service as 939 with improved undercarriage.
Avro Type F

  In the spring of 1912 A. V. Roe's fertile mind conceived the idea of an enclosed aeroplane affording the occupants complete protection from the elements. He straightway designed two such machines, the first of which was a single seat, mid-wing monoplane known as the Type F.
  Structurally similar to the Avro 500, it used the same undercarriage, tail unit and small rudder (this time linked to a steerable tail skid), but there the similarity ended. The box-girder fuselage was of streamlined shape built up from four wooden longerons and cross struts, reinforced by triangular plywood stiffeners in each bay and braced internally with piano wire. By unlacing the fabric half way along the rear fuselage to expose steel jointing plates, the fuselage could be taken apart quite easily to facilitate packing. Its maximum width was only 2 ft. but there was sufficient depth for the pilot to sit wholly inside with a somewhat restricted view through a number of celluloid windows. Entry was through a sheet aluminium trap-door in the roof and large circular holes were provided in each side through which the head could be thrust when flying in poor visibility. Fuel and oil tanks were situated inside the fuselage, remote from the engine to reduce risk of fire.
  The mainplane, constructed in two halves round a built-up front spar, was mounted on the centre line of the fuselage and braced by wires to a stout kingpost under the fuselage and to a pylon of steel tubes on top. Lateral control was by wing warping.
  The Type F monoplane was erected at Brooklands in April 1912 and Wilfred Parke made the first take-off on May 1, climbing the machine steeply on half throttle. It was the first flight in the world by an aeroplane with a totally enclosed cockpit. Critics predicted that oil thrown back by the 35 h.p. Viale five cylinder radial engine would completely obscure the pilot's vision but this proved not to be the case. It was a carefully maintained engine well known to Parke, being that taken from the Type D school machine which he had flown from Brooklands to Abingdon in the previous January. First circuits were made on May 3 and test flying continued until May 17 when, during a flight over Chertsey, 1,000 ft. was reached for the first time. On May 25 it was decided to show the machine at Hendon but the engine failed soon after take-off and in the ensuing forced landing at Weybridge, Parke hit a fence and turned over. There was little damage and the Type F was dismantled by four men in 25 minutes for return to the workshops.
  For some months the machine languished at Brooklands until taken out by R. H. Barnwell on September 13. After one or two straight hops, the front part of the skid was broken in landing and the aircraft turned over, suffering serious damage in the process. Barnwell was unhurt but it is evident that the Type F did not fly again.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plant: One 35 h.p. Viale
   Span 28 ft. 0 in. Length 23 ft. 0 in.
   Wing area 158 sq. ft.
  Weights: Tare weight 550 lb. All-up weight 800 lb.
  Performance: Maximum speed 65 m.p.h. Initial climb 300 ft./min.
  Production: One aircraft only, first flown at Brooklands 1.5.12, damaged beyond repair at Brooklands 13.9.12. Engine preserved at the Science Museum, London, and the rudder by the Royal Aero Club.
Avro Type G

  A. V. Roe's second cabin aeroplane was a two seat biplane designed specifically for the Military Aeroplane Competition of August 1912, and today historically important as the world's first cabin biplane. Very similar structurally to the Type F, the fuselage filled the whole mainplane gap and was again very narrow with a maximum beam of 2 ft. 3 in. tapering to only 15 in. at the front end. This was made possible by the use of a slim in-line engine mounted on steel bearers and enclosed in louvred cowlings with the main exhaust taken over the roof. As on the Type E prototype, cooling was by means of spiral tube radiators on each side of the cabin, entry to which was through triangular doors hinged to slanting struts in the sides of the fuselage. Mainplanes, undercarriage and tail unit were identical with those of the Avro 500. Once again there was no vertical fin and the steel shod rudder also acted as tail skid. Lateral control was by wing warping with a maximum warp at the tip of 18 in.
  Two Type G biplanes were laid down. One with a 60 h.p. Green engine to be flown by Wilfred Parke with competition number 6 and a second, numbered 7, for R. L. Charteris of the All-British Engine Co. Ltd. with a 60 h.p. A.B.C. eight cylinder engine. Unfortunately this A.B.C. engine was not ready in time and as a matter of expediency No. 7 was completed with the Green engine in place of No. 6.
  There was no time for test flying and the aeroplane was delivered in a crate direct to the competition ground at Larkhill on Salisbury Plain and there flown for the first time by Wilfred Parke. On August 7, 1912 he took off at the start of the 3 hours endurance test but after half an hour turbulent conditions compelled him to give up. Hurriedly landing down wind, he overturned and so damaged the machine that it had to be sent back to Manchester for repair. Exactly a week later on August 14, the machine returned, no doubt incorporating many components of the unfortunate No. 6. During the resumed trials Parke demonstrated the machine's all-weather qualities by flying in a rainstorm for 37 minutes and for half an hour in a wind of 40 m.p.h.
  At 6.04 a.m. on Sunday August 25, 1912 Parke again started on the endurance test carrying Lt. Le Breton as passenger. Just after 9 a.m. he commenced a series of steep dives to relieve the monotony and in so doing spun off a turn, but Parke's cool head and analytical mind were equal to the situation and he soon discovered that if the stick were central, recovery was possible by applying full opposite rudder. He was the second pilot to survive a spin but the first to do so before competent observers. In the ensuing discussions he gave a lucid account of what had taken place and today 'Parke's Dive' is recognised as an important milestone in the development of flying techniques. Later in that eventful day H. V. Roe flew as passenger to Upavon and became the first person to type a letter in an aircraft in flight.
  The Type G cabin biplane was an easy winner in the assembly test in a time of 14 1/2 minutes compared with the 9 hours 29 minutes of the Farman biplane and although the accident left insufficient time for the compilation of all the required data, the Avro company was awarded ?100 for attempting all the tests. The Type G failed to secure a major award because the initial rate of climb was poor (9 min. 30 sec. to reach 1,000 ft.).
  F. P. Raynham flew the machine home to Shoreham on October 11 but it had been in the open for so long that both engine and rigging needed attention. He therefore took the machine to Brooklands for adjustments on October 21 in 45 minutes and next day made an attempt to win the British Empire Michelin endurance prize. A broken water connection ended the flight after 3 1/2 hours but on October 24 he established a duration record for all-British aeroplanes with a time of 7 hours 31 minutes. Competing against Harry Hawker in the Sopwith Wright biplane, Raynham flew round Brooklands all day with the Green engine throttled right back to conserve fuel until forced to land through shortage of oil. His record stood for only an hour as Hawker went on to establish a new record of 8 hours 23 minutes and win the ?500 prize. The Type G biplane was afterwards flown back to Shoreham where it was last heard of in February 1913 hangared with the Type D biplanes of the Avro School.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Shoreham Aerodrome, Sussex
  Power Plant: One 60 h.p. Green
   Span 35 ft. 3 in. Length 28 ft. 6 in.
   Height 9 ft. 9 in. Wing area 335 sq. ft.
   Weights: Tare weight 1,191 lb. All-up weight 1,792 lb.
   Maximum speed 61.8 m.p.h. Initial climb 105 ft./min.
   Range 345 miles
  Production: One aircraft only, second machine not completed
Avro 501 and Avro 503 (Type H)

  The choice of Shoreham as the Avro company's new flying ground when it moved from Brooklands in the autumn of 1912 was largely the result of Cdr. Schwann's successful waterborne experiments and Avro's awakening interest in seaplanes. It was an ideal site with Shoreham Harbour close at hand and it was from the adjacent River Adur that the Avro Type H seaplane made its first take-off. Construction of this machine followed tests on Windermere by H. Stanley-Adams in January 1913 with the Avro 501 which, apart from a considerable strut-braced top wing overhang, was similar to an enlarged float-equipped Avro 500. Built at Brownsfield Mills in November 1912 and powered by a 100 h.p. Gnome, the Avro 501 first flew as an amphibian with a sprung central float designed by O. T. Gnosspelius, 15 ft. long and 7 ft. wide from which projected three small wheels, two in the rear and one forward. With so narrow a float an aircraft with a wing span of 47 ft. 6 in. could be expected to heel over when steerage way was lost, and for this reason small wing tip floats were fitted and inclined to sit squarely in the water. This arrangement proved unsatisfactory and Gnosspelius replaced it with a twin float unit without wheels which made the aircraft sufficiently seaworthy to interest the Admiralty, to whom it was eventually delivered in the Isle of Grain. In the light of experience at Barrow, the airscrew leading edges were sheathed with brass to prevent damage from flying spray and the tail float was bolted directly to the old-style sprung rudder for steering on the water.
  The float undercarriage of the old Avro 501 having proved far too heavy, the Admiralty agreed to accept it as a landplane. A. V. Roe thereupon devised a two-wheel, twin skid undercarriage but the track was still too narrow to support the aircraft vertically at rest and stout wing tip skids were necessary. In landplane form, with large inversely tapered ailerons replacing the constant chord units, the Avro 501 was so quaint a structure that it soon earned the name "Rickety Ann". After delivery to Eastchurch it had to be lightened and several airscrews tried before F. P. Raynham could complete the acceptance tests. Bearing naval serial 16 it was flown to Shoreham on June 2, 1913 by Raynham with Lt. Seddon as passenger.
  In the course of R.N. A. S. trials by F. P. Raynham at Eastchurch on August 28, 1913 a second landplane climbed to 3,000 ft. in 19 minutes with 36 gallons of petrol, 10 gallons of oil and 182 lb. of ballast. In the speed test 65.1 m.p.h. was reached and this aircraft, last of those ordered from A. V. Roe before the firm became a limited company, was followed by a float-equipped example which arrived at Sheerness in crates on September 8, 1913. On October 15 it was handed over to the R.N.A.S. in the Isle of Grain where it was joined eventually by an improved version built in the following December. One of these machines was damaged in a hangar fire at Eastchurch and sent to Brooklands for repair in July 1914.

  Manufacturers: A. V. Roe and Company (reconstituted as A. V. Roe, and Co. Ltd. 11.1.13), Brownsfield Mills, Great Ancoats Street, Manchester (moved to Clifton Street, Miles Platting, Manchester 4.13); and Shoreham Aerodrome, Sussex
  Power Plant: One 100 h.p. Gnome
  Dimensions, Weights and Performances:
   Avro 501 seaplane
   Span (upper) 47ft. 6 in.
   Span (lower) 39ft. 6 in.
   Length 33ft. 0 in.
   Height 12ft. 6 in.
   Wing area 478 sq. ft.
   Tare weight 1,740 lb.
   All-up weight 2,700 lb.
   Maximum speed 55 m.p.h.*
  *Landplane 65 m.p.h.

   Avro 501 seaplane, first flown on Windermere 1.13, converted to landplane serial 16, still airworthy in 1914
   At least one other landplane to R.N.A.S. Eastchurch and two seaplanes to R.N.A.S. Isle of Grain
Avro 501 and Avro 503 (Type H)

  The choice of Shoreham as the Avro company's new flying ground when it moved from Brooklands in the autumn of 1912 was largely the result of Cdr. Schwann's successful waterborne experiments and Avro's awakening interest in seaplanes. It was an ideal site with Shoreham Harbour close at hand and it was from the adjacent River Adur that the Avro Type H seaplane made its first take-off. Construction of this machine followed tests on Windermere by H. Stanley-Adams in January 1913 with the Avro 501 which, apart from a considerable strut-braced top wing overhang, was similar to an enlarged float-equipped Avro 500. Built at Brownsfield Mills in November 1912 and powered by a 100 h.p. Gnome, the Avro 501 first flew as an amphibian with a sprung central float designed by O. T. Gnosspelius, 15 ft. long and 7 ft. wide from which projected three small wheels, two in the rear and one forward. With so narrow a float an aircraft with a wing span of 47 ft. 6 in. could be expected to heel over when steerage way was lost, and for this reason small wing tip floats were fitted and inclined to sit squarely in the water. This arrangement proved unsatisfactory and Gnosspelius replaced it with a twin float unit without wheels which made the aircraft sufficiently seaworthy to interest the Admiralty, to whom it was eventually delivered in the Isle of Grain. In the light of experience at Barrow, the airscrew leading edges were sheathed with brass to prevent damage from flying spray and the tail float was bolted directly to the old-style sprung rudder for steering on the water.
  Also powered by a 100 h.p. Gnome, the Type H (later known as the Avro 503), was a slightly larger version of the Avro 501 but with less mainplane overhang and no inclined struts. Following standard Avro practice, the new seaplane was built with an eye to quick dismantling and was constructed round a 9 ft. centre section to which were bolted fuselage, undercarriage and outer wing panels. The upper mainplane, 3 ft. greater in span than the lower, was fitted with large inversely tapered ailerons but none was fitted to the lower wing. Two-step, internally sprung floats, 14 ft. long and 2 ft. 6 in. wide, set at a track of 6 ft. 6 in., were covered with rubberised material and attached to the aircraft by 14 tubular steel struts bound with varnished fabric.
  Such was his confidence in the Type H that F. P. Raynham made the first take-off from the Adur in sea mist on May 28, 1913 carrying passenger John Alcock, two hours' fuel and an anchor. The aircraft became airborne after a run of only 60 yards and cleared the adjacent railway bridge by 100 ft. Next day, again carrying the future conqueror of the Atlantic, Raynham made a first landing on the open sea outside Volk's seaplane hangar opposite Paston Place, Brighton. A float was damaged on take-off so a landing was made in Shoreham Harbour where the aircraft was hastily beached. After some local strengthening of the nose of each float the machine was out again on June 12 and two days later Raynham made an hour's demonstration flight over Brighton carrying Lt. J. W. Seddon R.N., Inspector of Naval Aircraft. Despite the weight and drag of the floats, the Type H climbed to 1,300 ft. in 5 minutes.
  The Avro 503 was then flown by Capt. Schultz, a German naval officer who had made several visits to the works while it was under construction, and before the month was out the machine was purchased by the German Government, dismantled and packed for shipment. Flown by Lt. W. Langfeld it became on September 3, 1913 the first aircraft to cross the 40 miles of North Sea from Wilhelmshaven to the Island of Heligoland, a successful return trip to Cuxhaven being made on September 15. An Avro 503 seaplane was also ordered by the Peruvian Government but the outbreak of the First World War prevented delivery and it is believed to have been turned over to the British Admiralty.
  At least-three other 100 h.p. Gnome-powered Avro 503s were built - all to Admiralty order for use by the Royal Naval Air Service. The float undercarriage of the old Avro 501 having proved far too heavy, the Admiralty agreed to accept it as a landplane. A. V. Roe thereupon devised a two-wheel, twin skid undercarriage but the track was still too narrow to support the aircraft vertically at rest and stout wing tip skids were necessary. In landplane form, with large inversely tapered ailerons replacing the constant chord units, the Avro 501 was so quaint a structure that it soon earned the name "Rickety Ann". After delivery to Eastchurch it had to be lightened and several airscrews tried before F. P. Raynham could complete the acceptance tests. Bearing naval serial 16 it was flown to Shoreham on June 2, 1913 by Raynham with Lt. Seddon as passenger.
  In the course of R.N. A. S. trials by F. P. Raynham at Eastchurch on August 28, 1913 a second landplane climbed to 3,000 ft. in 19 minutes with 36 gallons of petrol, 10 gallons of oil and 182 lb. of ballast. In the speed test 65.1 m.p.h. was reached and this aircraft, last of those ordered from A. V. Roe before the firm became a limited company, was followed by a float-equipped example which arrived at Sheerness in crates on September 8, 1913. On October 15 it was handed over to the R.N.A.S. in the Isle of Grain where it was joined eventually by an improved version built in the following December. One of these machines was damaged in a hangar fire at Eastchurch and sent to Brooklands for repair in July 1914.

  Manufacturers: A. V. Roe and Company (reconstituted as A. V. Roe, and Co. Ltd. 11.1.13), Brownsfield Mills, Great Ancoats Street, Manchester (moved to Clifton Street, Miles Platting, Manchester 4.13); and Shoreham Aerodrome, Sussex
  Power Plant: One 100 h.p. Gnome
  Dimensions, Weights and Performances:
   Avro 503 seaplane
   Span (upper) 50ft. 6 in.
   Span (lower) 47ft. 0 in.
   Length 33ft. 6 in.
   Height 12ft. 9 in.
   Wing area 567 sq. ft.
   All-up weight 2,200 lb.
   Maximum speed 50 m.p.h.
   Initial climb 225 ft./min

  Avro 503 prototype first flown at Shoreham 28.5.13, to the German Navy 6.13 with serial D12
  At least one other landplane to R.N.A.S. Eastchurch and two seaplanes to R.N.A.S. Isle of Grain
The original Avro 503 seaplane moored at Shoreham in June 1913.
Avro 504 to Avro 504H

  Design work on a successor to the Avro 500, begun at Brownsfield Mills in November 1912, was completed at the new Clifton Street works early the following year, Messrs. Chadwick and Taylor being responsible for the fuselage and undercarriage and H. E. Broadsmith the wings. Designated Avro 504, it was very lightly constructed with a rectangular section, wire braced, box-girder fuselage built from four ash longerons channelled for lightness and strengthened by flanges. Cross struts were of spruce. For maximum view the pilot sat in the rear, the passenger occupying the front cockpit, from the corners of which four ash struts supported the centre section. Equal span, two bay wings were rigged with 2 ft. stagger and braced by streamline section, hollow spruce interplane struts pin-jointed to the spars. Each wing panel consisted of five main ribs with spanwise stringers supporting a number of contour-forming strips of wood anchored to leading and trailing edges. Lateral control was by inversely tapered ailerons rigidly fixed at the inner end, the widened outer ends of which were warped by means of cables.
  Although similar to that of the Avro 500, the undercarriage was a much improved and simplified unit. An ash skid was anchored to the fuselage by steel Vee struts as before, but the axle was no longer bolted to it and was no longer a laminated spring. Instead, a simple steel tube axle was used in conjunction with two main undercarriage legs having built-in rubber shock absorbers (8 ft. 8 in. of bungee cord wound round the two halves of the leg) in streamlined cases. The tail skid was attached to the bottom of a comma-type rudder.
  In design, construction and performance the Avro 504 was considerably in advance of other 1913 types and benefited from the use of an improved wing section. Power was supplied by one of the new 80 h.p. Gnome rotaries (the actual power output of which is said to have been nearer 62 h.p.) installed in a square section cowling bulged on top and sides.
  To give it the widest possible publicity the Avro 504 was entered for the 1913 Aerial Derby and consequently was built in considerable secrecy. Its arrival at Hendon on September 20, 1913, morning of the race, was therefore something of a sensation as it was obviously very fast and the impression of speed was heightened by its staggered mainplanes. When F. P. Raynham crossed the finishing line in fourth place at an average speed of 66.5 m.p.h., few realised that the Avro 504 was virtually untried, having been delivered at Brooklands only three days before (September 17), and flown for the first time on the following day.
  After the Aerial Derby the Blackburn Aeroplane and Motor Co. Ltd. issued a challenge to its Lancashire rivals and on September 29 Raynham flew the Avro 504 from Brooklands to Leeds for a race against a new Blackburn monoplane flown by Harold Blackburn. The 100 mile race was held on October 2 over a course starting and finishing at Leeds and passing over York, Doncaster, Sheffield and Barnsley. With H. V. Roe as passenger, Raynham flew neck and neck with Blackburn until bad visibility forced him to land near Barnsley.
  Although basically a sound aeroplane the 504 needed modification and went back to the Manchester works where the engine mounting was changed for an improved version carrying more streamlined cowlings. Aileron control was also lightened by replacing the warping arrangement with constant chord hinged ailerons with wires to complete the circuit in place of the original rods. The wing structure was strengthened by replacing the hollow pin-jointed interplane struts by solid ones fitted in metal sockets. Redelivered at Brooklands at the end of October, the 504 was flown a great deal by Raynham during the following month. He made a forced landing at Horley with a broken carburettor control during the Hendon-Brighton-Hendon race on November 8; flew from Brooklands to Farnborough and back on November 15; gained second place in the Shell Trophy Race at Hendon the same afternoon and broke the lap record at 73 m.p.h.; spent a week on day and night flying at Shoreham and flew to Farnborough for official tests on November 24. With a passenger and fuel for three hours the Avro 504 clocked 80.9 m.p.h. over the measured mile and climbed to 1,000 ft. in 1 min. 45 sec.
  An outstanding performance put up by Raynham on February 4 was a climb to 15,000 ft. over Brooklands. This exceeded the existing British altitude record by almost 2,000 ft. but was not an officially observed record. During the descent Raynham shut off his engine, put the machine into a glide, and 25 minutes later was at 5,000 ft. over Hendon some 20 miles away. He then spiralled down to a landing, still without using his engine. Carrying R. J. MacGeagh Hurst in the front seat Raynham made an officially observed climb to a record height of 14,420 ft. over Brooklands on February 10.
  Later in the season the machine was purchased by the Daily Mail and toured the country giving passenger flights piloted by F. P. Raynham and G. Lusted. A. V. Roe and Co. Ltd. built an interchangeable twin float undercarriage so that the machine could be flown off the sea at coast resorts. At the same time the original 80 h.p. Gnome was replaced by an 80 h.p. Gnome Monosoupape which was supposed to give more power but which in fact gave only trouble. First flights as a seaplane took place at Paignton in April 1914, after which it visited Falmouth, Southport and Ireland but when war was declared on August 4 the machine was at Shoreham where it was immediately commandeered. Two days later the career of this historic aeroplane ended when the engine failed as Raynham took off to deliver it to the R.N.A.S. With no height in hand there was no alternative to putting the machine down on land where it was damaged beyond repair.
  Series production of the Avro 504 began in the summer of 1913 when the War Office placed a contract for 12 machines. This brought about some restressing of the wings to comply with their strength requirements which included doubling the depth and width of the rear spar. Others were built for non-military and experimental purposes, one of which was exhibited at Belle Vue, Manchester on January 1-3, 1914 and another, delivered at Brooklands on February 16, was fitted with the first Armstrong Whitworth-built 100 h.p. A.B.C. engine. After endless engine runs Raynham made what was possibly its only flight with this engine early in April. Drawings were also prepared for the installation of a 65 h.p. Austro-Daimler engine but as far as is known this scheme was shelved. A third Avro 504 was exhibited with rubber-sprung float undercarriage at the Olympia Aero Show in March 1914 and another was delivered to Harold Blackburn at Southport in July. In common with thousands of Avro 504 variants built in later years, these aircraft were noticeably different from the prototype because the top longerons sloped downwards aft of the cockpits to make the fuselage symmetrical in side elevation.
  Two Avro 504s, almost the last of the 12 War Office machines, were delivered at Brooklands on June 5, 1914 and it was in one of these on June 12 that F. P. Raynham succeeded in looping a 504 for the first time. They were delivered next day to Farnborough where 376 (probably the first machine of the batch) was tested to destruction during July. A few Avro 504s were among the aircraft of No. 5 Squadron R.F.C. when it left for France on August 13, one of which became the first British aeroplane brought down by the Germans when Lts. V. Waterfall and C. G. G. Bayly were hit by infantry fire in Belgium on August 22. In mid-October, 383, another Avro of the squadron was fitted with a Lewis gun by 2nd-Lt. L. A. Strange whose gunner, Capt. L. da C. Penn-Gaskell straffed a troop train at Perenchies and forced down an Albatros two seater near Neuve-Eglise a month later. Only a few Avro 504s saw frontline service and the greatest number in R.F.C. squadrons in France at any one time was thirteen.
  The Admiralty placed an order in the spring of 1914 for one Avro 504 and for six others a few months later. The first of these was delivered to the R.N.A.S. Eastchurch Squadron on November 27, 1914. Armed with four 16 lb. bombs and piloted by Flt. Sub-Lt. R. H. Collet, an attempt to bomb the Bruges submarine depot on December 14 was foiled by bad visibility and an attack was made on the Ostend-Bruges railway instead. Very few offensive sorties were made by the Avro 504, the most ambitious being the brilliant and historic raid on the Zeppelin sheds at Friedrichshafen. A special flight of four machines formed at Manchester in October 1914 by Sqn. Cdr. P. Shepherd, was equipped to carry four 20 lb. bombs per aircraft and shipped from Southampton to Le Havre. They arrived at Belfort by train on the night of November 13, 1914 and were hidden in a barn for fear of arousing the suspicions of local spies. It was not possible to flight test them and the first machine, 874, took off untried at 9.30 a.m. on November 21 piloted by Sqn. Cdr. E. Featherstone Briggs. Flt. Cdr. J. T. Babington then left in 875 followed by Flt. Lt. S. V. Sippe with five minutes separation in 873. Flt. Sub-Lt. R. P. Cannon's machine 179 (the first Avro 504 built for the R.N.A.S.) broke its tail skid and could not go. The raiders followed the Rhine at 5,000 ft., crossed Lake Constance at 10 ft. and put several bombs into the airship sheds from 1,200 ft. They narrowly missed destroying naval Zeppelin L.7 but hit the gas plant which exploded with considerable violence. Briggs was shot down but the others made the 125 mile return trip in safety after four hours in the air. Flown by Flt. Lt. H. L. Rosher, Sippe's Avro 873 was one of five belonging to No. 1 Sqn. R.N.A.S. which twice bombed Ostend and on March 24, 1915 destroyed two U-boats in an attack on the submarine depot near Antwerp. Together with 179 and 875, it survived to return to England for overhaul and transfer to school work.
  When the Avro 504 was relegated to training, a duty it was destined to fulfil with distinction for over 15 years, A. V. Roe and Co. Ltd. designed and supplied a self contained dual control unit comprising seats, control columns and rudder bars. Later in 1915 converted machines were joined by a number specifically built as trainers, total Avro 504 production amounting to 63 aircraft. As the war progressed, modification gave rise to a series of variants. The Avro 504A, built for the R.F.C, was a strengthened version with wide chord interplane struts and ailerons of reduced span. The lower wing roots were sometimes stripped of fabric to improve the downward view and 2905, delivered on January 17, 1916, was used at Farnborough for fabric tests. At least B3103 was fitted with an improved undercarriage having rear shock legs and front radius rods for use by the C.F.S. Communications Flight at Lopscombe Corner, Salisbury in 1918.
  The Admiralty insisted on wing spars of greater cross section and was supplied with a drastically modified version known as the Avro 504B. It reverted to long span ailerons and was identified by a large, unbalanced rudder hinged to a considerable dorsal fin. The top longerons were recessed to provide curved cut-outs in the sides of the rear cockpit. A stout ash tail skid, sprung with rubber cord and hinged to a pylon under the rear fuselage, became standard fitment on this and all subsequent 504 variants. A few R.N.A.S. Avro 504Bs were used operationally at Dunkirk, including 9890 and N5267 which had forward-firing guns and interrupter gear. A pioneer Zeppelin interception was also made by an Avro 504B from R.N.A.S. Westgate piloted by Flt. Sub-Lt. Mulock who made contact with L.Z.38 in the early hours of May 17, 1915. The airship climbed too rapidly for him to use his armament of two hand grenades and two incendiary bombs but later the same night the Avro 504B 1009, piloted by Flt. Cdr. A. W. Bigsworth, pursued L.Z.39 towards Ostend with more success. He managed to gain sufficient height to drop four 20 lb. bombs on the airship's stern and caused slight damage by fire which led to a heavy landing at Evere, Brussels.
  The majority of Avro 504Bs were naval trainers and late production models had the 80 h.p. Le Rhone, provision for Scarff ring and no cut-outs to the rear cockpit. At least one was used in early deck landing arrester gear experiments. In the coastal reconnaissance role the endurance was increased to 4 1/2 hours but this soon proved insufficient and 80 examples of a single seat version having 8 hours endurance were built. Powered by an 80 h.p. Gnome and known as the Avro 504C, it had a large cylindrical fuel tank in place of the front cockpit and a gap in the top centre section through which a Lewis gun could fire incendiary ammunition upward at an angle of 45 degrees. The R.F.C. equivalent, conceived in 1916 under the designation Avro 504D, retained the balanced comma-type rudder and short span ailerons, but had the recessed longerons and wing root modifications of the Avro 504C. Serial allocation suggests that six 504Ds were ordered but there is no evidence that they were actually built.
  Modification on this scale led to a severe weight penalty and additional power had become a dire necessity. The next R.N.A.S. variant, the Avro 504E, was therefore fitted with the 100 h.p. Gnome Monosoupape. At the same time the rear cockpit was moved farther aft and the change of C.G. position caused by installing the main fuel tank between the cockpits was counteracted by reducing the stagger from 24 to 9 in. Centre section struts were then repositioned to converge towards the top in side elevation. The 504E also reverted to the straight top longerons of the prototype but was fitted with the fin, rudder and ailerons of the 504B. Ten were built, some of which were used at Chingford and Fairlop and one at Cranwell.
  Designation Avro 504F was given to a single Avro 504C 8603 fitted at the suggestion of the Admiralty with a 75 h.p. Rolls-Royce Hawk six cylinder inline engine. It was evidently an unsuccessful union as a contract for 30 Avro 504F aircraft was cancelled and replaced by one for the 80 h.p. Gnome version.
  Uncertainty still shrouds the precise identity of the Avro 504G, described by Avro works manager R. J. Parrott in 1925 as an R.F.C. gunnery trainer, ten examples of which were built with 130 h.p. Clergets and equipped with synchronised front Vickers gun and rear Lewis. Designation Avro 504G was used also by the R.N.A.S. for the 80 h.p. Gnome-powered Avro 504B conversions having synchronised front Vickers guns and a Scarff ring on the rear cockpit.
  Last of the early exploratory variants was the 504H, a strengthened 504C fitted under the supervision of Sqn. Cdr. E. H. Dunning in 1917 with catapult pick-up points and a special padded seat. Piloted by Flt. Cdr. R. E. Penny this machine later became one of the first aircraft successfully launched by catapult.
  At this stage of the war orders for the several variants were far in excess of production capacity at Manchester and a number of sub-contractors were brought in.

   A. V. Roc and Co. Ltd., Clifton Street, Miles Platting, Manchester
   The Bleriot & Spad Aircraft Works, Addlestone, Surrey
   The Brush Electrical Engineering Co. Ltd., Loughborough
   The Eastbourne Aviation Co. Ltd., Eastbourne
   The Humber Motor Co. Ltd., Coventry
   Parnall and Sons, Mivart Street, Eastville, Bristol
   The Regent Carriage Co. Ltd., Fulham, London
   S. E. Saunders Ltd., East Cowes, Isle of Wight
   The Sunbeam Motor Car Co. Ltd., Wolverhampton
  Power Plants:
   80 h.p. Gnome
   80 h.p. Gnome Monosoupape
   (Avro 504 and 504A)
   80 h.p. Gnome
   80 h.p. Le Rhone
   100 h.p. A.B.C.
   (Avro 504B)
   80 h.p. Gnome
   80 h.p. Le Rhone
   (Avro 504C and 504D) 80 h.p. Gnome
   (Avro 504E) 100 h.p. Gnome Monosoupape
   (Avro 504F) 75 h.p. Rolls-Royce Hawk
   (Avro 504G and 504H) 80 h.p. Gnome
   Span 36 ft. 0 in. Length 29 ft. 5 in.
   Height 10 ft. 5 in. Wing area 330 sq. ft.
  Weights and Performances:
   Prototype Avro 504 landplane seaplane Avro 504A Le Rhone
Tare weight - 924 lb. 1,070 lb. 1,050 lb.
All-up weight 1,550 lb. 1,574 lb. 1,719 lb. 1,700 lb
Maximum speed 81 m.p.h. 82 m.p.h. 75 m.p.h. 86 m.p.h.
Climb to 3,500 ft. 7 min.* - - 7 min.**
Endurance 3 hours - - 4 1/2 hours***
*With 80 h.p. Gnome Monosoupape.
**With 80 h.p. Gnome 9 min. 30 sec.
***With Avro 504C and 504D 8 hours.

Avro 504J and Avro 504K

  In the autumn of 1916 a more powerful version of the Avro 504A with the 100 h.p. Gnome Monosoupape was produced for the R.F.C. This variant, designated 504J and known in the R.F.C. as the "Mono Avro", was externally identical with the earlier type and large numbers ordered as 504As were completed as 504Js.
  Among the first recipients of the Avro 504J was the School of Special Flying founded at Gosport in July 1917 by Maj. R. R. Smith-Barry. Here (and later at similar schools at Shoreham, Lilbourne, Redcar, Ayr and Curragh) instructors were introduced to Smith-Barry's revolutionary flying training technique, a system based on demonstration and explanation by an instructor who was in verbal communication with the pupil. The 'Gosport' speaking tubes specially designed for this purpose were still to be found in club aircraft half a century later. The Avro 504J was fully aerobatic and made an ideal training aircraft because its light and powerful controls quickly showed up faults in a pupil's flying. It is now historically important as the aeroplane which made possible a system of training which, in modified form, became part of the R.A.F.'s Flying Training School syllabus for more than 40 years. As the standard R.F.C. trainer, the Avro 504J was ordered in such quantity that contracts were placed with additional sub-contractors. Components for Avro-built machines were constructed in Manchester for erection at the company's new aerodrome at Hamble.
  In his memoirs C. A. Nepcan Bishop recalls that the Gosport School Avro 504J C4448 was the personal machine of Capt. Williams whose favourite trick was to land between the hangars, touch down on the tarmac, swing completely round and finish the landing run inside 'C' Flight hangar. Among other Gosport instructors were Maj. E. L. Foote who was to become well known as airline, test and sporting pilot in the years immediately after the War, and Capt. Duncan Davis, manager of Avro's South Coast joyriding aircraft in 1919-20 and C.F.I, of the Brooklands School of Flying in the 1930s. A distinguished pupil was H.R.H. Prince Albert (later King George VI) who learned to fly on C4451. In 1918 a team of instructors took four Mono Avros across the Channel to demonstrate the Gosport system to the French.
  By the end of 1917 the 100 h.p. Gnome Monosoupape was outmoded as a front line power plant and British production of this engine was allowed to tail off. To prevent interruption of Avro 504J production through engine shortage, all surplus rotaries, including 80 h.p. and 110 h.p. Le Rhones as well as 130 h.p. Clergcts, were collected from English and French aerodromes. There was no difficulty in fitting the 80 h.p. Le Rhone and a number of 504Js were thus powered, but it was necessary to modify the front fuselage before larger engines could be installed. Following the trial installation of a 130 h.p. Clerget in B3157 for Smith-Barry at Gosport at the end of 1917, the Technical Dept. of the Air Board asked A. V. Roe and Co. Ltd. to produce adaptors and a new type of universal engine mounting. In the older machines this was of the two bearer type, the front bearer being in the form of a ball race supported on four tubular arms forming extensions to the fuselage longerons. This 'spider' was now replaced by an overhung mounting designed by H. E. Broadsmith which consisted of two bearer plates which would accept any suitable engine and allow the use of a smooth open fronted cowling. Irrespective of the type of engine fitted, aircraft built with this mounting were known as the Avro 504K, even though many had been ordered as 504Js or even 504As. The original 'Clerget Avro' B3157 joined 'F' Flight, School of Special Flying, and crashed at Gosport on March 2, 1918.
  With standardisation accomplished the way was clear for greatly increased production and the Avro company was authorised to plan the construction of 100 machines a week, plus spares. They were also required to produce 20 sets of knock down parts per week for assembly at the Eastern Aircraft Factory at Aboukir, Egypt and by the Armistice production had reached 80 Avro 504Ks a week, including 20 sets of components for Aboukir.
  As a result of demonstration flights over Washington by Avro 504J C4312 imported by the British Mission under Col. Lee in the winter of 1917-18, fifty-two Le Rhone engined 504Ks were purchased by the Americans in July 1918. These were used by the A.E.F. for advanced training at No. 3 Instruction Centre, Issoudun, France, and after the War survivors were shipped to the U.S.A., where one or two still exist.
  Major modification of the Avro 504J was confined to the fitting of short span, single bay wings and curved fin to B4264 at Gosport in January 1918. Standard 36 ft. mainplanes were eventually replaced, rigged experimentally with the gap reduced from 5 ft. 6 in. to 5 ft. 1 1/4 in. In March 1918 the same set of short span wings was fitted temporarily to B3155, a two seater with shortened fuselage and armed with a Lewis gun. In the following May it flew as a single seater with the fuel tank in the front cockpit, and this led logically to the first of a number of 110 h.p. Le Rhone engined single seat 504Ks for high altitude work with Home Defence Squadrons in the north of England. These had the gravity tank repositioned to port to make way for a Lewis gun on the top centre section, and with front cockpit faired in could reach 18,000 ft. Some were fitted later with a low drag Vee-type undercarriage similar to that of the Avro 521. Two so modified were flown at Gosport - C605 with 130 h.p. Clerget on June 15, 1918 and C604 with Le Rhone on February 3, 1919.
  Total wartime production of Avro 504s of all marks exceeded that of any other type of British aeroplane but the oft quoted figure of 8,340 aircraft (3,696 by A. V. Roe and 4,644 by sub-contractors) is obviously in excess of the actual total. Nine were delivered to the Expeditionary Force in France in 1914; 4,771 to training units; 274 to Home Defence Units; 392 to the Middle East Brigade and 52 to the Americans. When the R.F.C. and R.N.A.S. came under unified command on April 1, 1918, Avro 504Js and Ks were in use with almost every Service unit in Britain so that on October 31, 1918 there were 2,999 on R.A.F. charge (including 2,267 at flying schools and 226 on Home Defence). One hundred and eleven were in Egypt and Palestine, where some were pressed into emergency air mail service during the Egyptian rising of March-April 1919.
  In 1919 the Sunbeam Motor Co. Ltd., sub-contractor for the Avro 504B, J and K, fitted one of its 100 h.p. water cooled Dyak airship engines into a 504K airframe. With brass nose radiator and attendant plumbing it was a heavy power plant which substantially reduced payload. Conversions were consequently few but two were supplied to Norway in 1920 and several were built for civil use with the Dyak engine in Australia in 1922.
  The Royal Aircraft Establishment found the 504K a most useful test vehicle in the years immediately after the war, and each of Farnborough's resident machines was used for a wide variety of experimental flying. One important phase was flight testing a number of wings designed by Boulton and Paul, Humber, Vickers and the Steel Wing Company with metal spars and/or ribs. The metal wing programme was initiated partly through timber shortage but chiefly because seemingly identical wooden spars varied considerably in strength and weight. Minor experimental devices flown on the 504Ks ranged from a Leitner-Watts metal airscrew to a windmill-driven clear vision rotating windscreen.
  A postwar gunnery trainer version of the Avro 504K (130 h.p. Clerget) was designated Avro 540 but differed from standard only in the region of the rear cockpit which was strengthened and built up to take a Scarff mounting for a rear gunner. There was no new production, the few that existed being converted 504Ks.
  Of greater importance was the 504K's contribution to low speed flying research in the course of which H2402 was fitted with a Vee-type undercarriage, water ballast tanks near the C.G. and in the tail, as well as an immense fin and unbalanced rudder. Eleven gallons of water could be pumped into the rear tank in the air to enable the aircraft to fly at very large angles of incidence (up to 35 degrees) with the object of exploring controllability in stalled flight and so reduce the risk of hitting the ground in a nose-down attitude as described in R. & M. 991. In the event, H2402 experienced almost uncontrollable longitudinal oscillations and a second machine, F8940, with similar undercarriage, fin and rudder, was flown with variable incidence tailplane and lead weights up to 80 lb. over the tail skid. Large range differential ailerons allowing upward angles in excess of 90 degrees and interconnected with leading edge slots, were actuated by a wheel mounted on the control column. Research also embraced balanced ailerons mounted at mid-gap and concluded with flight tests by E3269 equipped with Handley Page slots interconnected with Frise-type balanced ailerons. This aircraft was demonstrated sensationally by F/Lt. P. W. S. Bulman at Farnborough on April 15, 1925.
  The 504Js were declared obsolete in September 1921 but the 504K remained in service as the standard R.A.F. trainer with the C.F.S. and Nos. 1, 2, 3, 4 and 5 Flying Training Schools until the late 1920s. It also served with No. 24 (Communications) Squadron; with Nos. 600, 601, 602 and 603 Auxiliary Air Force Squadrons; and with Fleet Air Arm training units at Netheravon and Leuchars. It took part in Hendon R.A.F. Displays, commencing in 1920 when F/O Quinland cavorted 'L'Avro Comique' B3292 with extra large four speed and reverse gear box, be-cobwebbed undercarriage, vacuum cleaner, anchor, kettle, flue pipe, jazz painted interplane struts and four dummy heads! The Display of July 3, 1921 included a standard Avro race won for Kenley by F/O P. Murgatroyd who won again in the following year while representing Cranwell. Crazy flying by F/Lt. Jack Noakes in 1921 and F/Lt. W. H. Longton in 1922 brought congratulations from King George V. The Avro 504K made its final appearance in a star role in 1923 as the 'Orva Mayfly', which paraded in front of the crowd with 'A.B.C. Lion' engine, wireless clothes line, kettle, chimney, six inch gun and carrot accelerator!
  The last Avro 504Ks, built by A. V. Roe to Contract 707157/26, appeared in two batches. The first 40, delivery of which was completed on November 11, 1926, were followed by 10 delivered by January 17, 1927.
  In 1963 several Avro 504Ks survived in the U.K. in military markings. D7560, fitted with the wings of E3104, property of the Science Museum, London, was on permanent exhibition until stored in 1939. H2311, flown down from Scotland under another identity by F/Lt. Birch to join the Nash Collection at Brooklands in 1938, was overhauled by A. V. Roe and Co. Ltd. for the Royal Aeronautical Society in 1950 and flown at the Farnborough R.A.F. Display by Gp. Capt. L. S. Snaith in July of that year. After a period in store at Hendon and London Airport, it was transferred to Upavon in 1962. A third 504K, c/n R3/LE/61400, which had been stored for many years by the Shuttleworth Trust at Old Warden, was rebuilt by apprentices at the Chadderton works of A. V. Roe and Co. Ltd. Fictitiously numbered E3404, this machine flew again in 1955 and took part in the film "Reach for the Sky". It is still flown on rare occasions, as at the Fifty Years of Military Aviation display at Upavon on June 16, 1962.

   A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
   Australian Aircraft and Engineering Co. Ltd., Sydney, N.S

Avro 504K (civil)

  The vast armada of Avro 504Ks rendered surplus by the 1918 Armistice included not only wartime training veterans but also large batches of new machines at storage units or still in the factories. An offer by A. V. Roe and Co. Ltd. to repurchase them en bloc was refused on the grounds that the Disposal Board found it impossible to compute the precise number of saleable aircraft. Sales therefore began by public auction at No. 1 Aircraft Salvage Depot, Hendon, but in 1920 Handley Page Ltd. bought all Disposal Board stocks and the 504Ks were thereafter marketed by its subsidiary, the Aircraft Disposal Co. Ltd. of Croydon. Trade was brisk despite the late G. P. Ollcy's forced landing on March 31, 1920 in Southwark Park pond in the company's demonstrator G-EAHW (130 h.p. Clerget). Foreign and Commonwealth governments made considerable inroads into stocks but even greater numbers were sold for civilian use. Low first cost and a seemingly endless spares backing, made the Avro 504K the only military aircraft of the period to find lasting favour as a civil type. Between 1919 and 1930 over 300 were allotted civil registrations in Britain alone and before the advent of the D.H. Moth in 1926 the Avro 504K was the most common British aeroplane. The majority had the dual controls removed and the decking cut away to make room for a third seat but a few were used for flying instruction and the total included a number ferried abroad in temporary civil marks.
  Civil flying was sanctioned in Britain at Easter 1919, a memorable Bank Holiday when A. V. Roe's immortal trainer embarked on an even greater career as a pleasure trip machine. Its usefulness extended over two decades and its name will be linked for ever with the halcyon days of itinerant joyriding, the story of which falls into four clearly defined periods.
  Excited by the deeds of great wartime pilots, the public developed a thirst for flying which earned every airworthy 504K a handsome living for the rest of 1919. Despite an ambitious essay into organised pleasure flying by the Avro company, lesser concerns also made a great deal of money, particularly in Scotland. Quick to fill the gap when Avro withdrew from the business in 1920, many former R.A.F. pilots bought 504Ks in the hope of reaping similar rewards but over 50 such mushroom enterprises were ended within the year by the trade slump. The third period, which lasted until the end of the decade, saw Avro pleasure flight business reduced to a number of old established firms run by a handful of seasoned pilots whose lives were dedicated to the game. Their eventual absorption into the great air displays of the 1930s brought the career of the 504K to an end as it had begun, in organised joy flying on the grand scale.

Avro 504K (overseas)

  In 1919-20 the British Government made each Dominion an Imperial Gift of surplus Avro 504Ks and other aircraft, and during the next 12 years large numbers of additional 504Ks were stripped, overhauled and test flown at Croydon by the Aircraft Disposal Co. Ltd. for military and civil use overseas. Vickers Ltd. and A. V. Roe and Co. Ltd. were also heavily engaged, the latter completing 100 504Ks in 1921 alone. Manufacturing rights were also sold in Japan and elsewhere.

Avro 504L

  First peace-time 504K variant was the Avro 504L training seaplane. The prototype conversion, C4329, used two wooden, pontoon-type, single step main floats, each attached to the fuselage by two steel struts, as well as tail and wing tip floats bolted directly to the main structure. A large curved fin was fitted to compensate for the extra keel surface forward and the fairing of the fuselage sides was improved to conform more closely to the shape of the cowling. To give a reasonable take-off performance the higher powered 130 h.p. Clerget was fitted and trials conducted at Hamble in February 1919 led first to the fitting of a four bladed airscrew and the removal of the small wing tip floats. Later the main undercarriage was strengthened by means of an additional strut to the rear of each float.
  The Avro 504L did not meet any R.A.F. requirement and was not adopted, nevertheless the Avro company built a considerable number of float undercarriages. The Hamble works also produced six short range float-equipped three seatcrs for the Avro Transport Company. Still more power was needed and a proposal to fit the new 170 h.p. A.B.C. Wasp I radial was turned down after trials with this engine in K-147, a 'guinea pig' 504K from the same production batch. The 150 h.p. Bentley B.R.I rotary therefore became the standard engine and drove a two bladed airscrew.
  G-EANB, last of the six, was certificated too late in the season to be gainfully employed but the other five were all used for joyriding. Piloted by Capt. F. Warren Merriam one worked the Isle of Wight resorts and Hayling Island, and the others went to Paignton, Devon. Flights over Torbay and to Teignmouth proved very popular and 250 passengers were carried during August-September 1919. On August 25, two 504Ls (in all probability K-145 and G-EAJX), flew along the South Coast en route to an autumn joyriding season at the First Air Traffic Exhibition, Amsterdam. One refueling in Dover Harbour but the other forced landed off Ramsgate with petrol shortage and had to be towed in. Their replacements G-EALH and 'LI were withdrawn to Hamble but K-146 (Capt. Evans) was wrecked off Alderney in fog on October 5 while carrying newspapers to Guernsey.
  Operations begun on Windermere under C. Howard Pixton on August 4, 1919 were quite remarkable. His aircraft were not true 504Ls but float-equipped 504Ks (130 h.p. Clerget) and without the third undercarriage strut. In common with the majority of Avro Transport Company machines at that time, they flew with enlarged Service markings, in this case H2581 and '82 (later G-EADJ and 'DK). They used the slipway and hanger at Bowness formerly occupied by the Lakes Flying Company and continued the lucrative pleasure flights pioneered eight years earlier by the Avro-built Water Bird. The suspension of night mail boat services to the Isle of Man also gave Pixton the opportunity of making twelve 90 minute early morning crossings to Douglas with 3 cwt. parcels of the Daily News.
  The Eastbourne Aviation Co. Ltd. embarked on a South Coast joyriding season of its own and produced six float-equipped 504Ks. These were also without the third undercarriage strut, and the three occupants sat one behind the other in separate cockpits. The enterprise ended late in 1920 with a seaplane race as grand finale at Hove, Sussex, on August 19 during which G-EAJH sank with a collapsed undercarriage. Maj. J. P. B. Ferrand carried 350 passengers in the former Windermere machine G-EADK at Folkstone in 1920 but Avro waterborne activities then ceased round the British Isles. In 1921 the Aircraft Disposal Co. Ltd. sold the new production 504L G-EANB and two others (almost certainly H1911 and 72) in Sweden to Kungl. Vattenfallsstyrelsen (Royal Waterfalls Committee) as S-IAA, 'AB and 'AG. They were used in connection with power station construction in North Sweden. Later two were flown inside the Arctic Circle for seven months by Gosta Hulstrom and Ing. Holmen who made 106 return journeys between Porjus and Suorva, flew 23,820 km. in 202 hours 53 minutes flying time and carried 362 passengers plus 6,681 kg. of mail. One Eastbourne 504L, G-EASD purchased for ?400 by Ing. G. Spaak, also went to Sweden in 1921.
  Activities elsewhere were confined to idyllic flights from Bermudan beaches in 1920 by two 504Ls of the Bermuda and Western Atlantic Aviation Co. Ltd.; from Manly Bay, Sydney Harbour, by one of the Australian Aircraft and Engineering Company's imported machines (without dorsal fin) and later by two Imperial Gift 504Ls of the R.A.A.F.; at Mission Bay, Auckland, by two Imperial Gift aircraft of the New Zealand Flying School; in Canada where a few Imperial Gift float undercarriages were brought into use to enable 504Ks to operate from lakes on forestry patrol; and at Valparaiso where three 504L trainers (130 h.p. Clerget) were used by the Chilean Naval Air Service.
  A British Mission led by Col. the Master of Sempill, sent out to advise the Imperial Japanese Navy in 1921, took with it a selection of British machines including ten Hamble-built Avro 504Ls. Maj. Orde-Lees and Mr. H. Crisp trained the first Jap naval pilots on these at Kasumigaura, near Tokyo, from which on September 3, 1921 they made a mass formation flight to escort the Crown Prince's warship and all landed in Yokosuka Harbour. When Japan purchased the manufacturing rights from A. V. Roe, Bentley powered 504Ls were built for the Navy by Nakajima. They were without the strengthened undercarriages and their performance deteriorated considerably when the B.R.ls wore out, the only available replacement engine being the licence built 110 h.p. Le Rhone (see p. 124). One Avro 504L remained in service with the Japan Air Transport Research Institute of Osaka until 1927.

   A. V. Roe and Co. Ltd., Hamble Aerodrome, near Southampton, Hants.
   The Eastbourne Aviation Co. Ltd.
   Nakajima Hikoki Seisaku Sho (Nakajima Aircraft Manufacturing Co.), Ohta-Machi, Tokyo, Japan
  Power Plants:
   One 110 h.p. Le Rhone
   One 130 h.p. Clerget
   One 150 h.p. Bentley B.R.I
   Span 36 ft. 0 in. Length 32 ft. 1 in.
   Height 11 ft. 4 in. Wing area 330 sq. ft.
   Weights: Tare weight 1,408 lb. All-up weight 2,006 lb.
   Maximum speed 87 m.p.h. Cruising speed 75 m.p.h.
   Initial climb 650 ft./min. Endurance 2 hours
  *With 130 h.p. Clerget engine.

Avro 504M

  In the spring of 1919 Hamble was very busy converting Avro 504Ks for the Avro Transport Company and produced the six 504Ls, a number of Avro 536 five seaters and single examples of two dissimilar cabin variants. First of these, built in April of that year, was the Avro 504M, a standard 504K modified above the top longerons to form a claustrophobic enclosure accommodating two passengers in staggered seats behind the pilot.
  A curved plywood roof with two glazed portholes in each side was hinged along the port longeron. After it was opened the pilot entered by raising a further section of roofing, and once in, viewed the landscape through five vertical Triplex panels mounted round the edge of the cockpit. A light fabric covered structure faired the cabin smoothly into the tail and additional side area was compensated by the addition of a 504L-type dorsal fin. Despite the considerable weight penalty, improved streamlining made it faster than the standard 504K.
  The Avro 504M was unusual among British civil Avros in having a 100 h.p. Gnome Monosoupape nine cylinder rotary. It was certificated on June 25, 1919 with the temporary registration K-134 and next day R. F. Park flew it to Chorley Wood Common, Bucks, to pick up a newly married pair outside the church. After a refuelling stop at Bournemouth, the 504M landed the honeymoon couple at Fowey, Cornwall, in an elapsed time of four hours. The machine then returned to Hounslow Heath and spent the rest of the summer doing a roaring trade among ladies wishing to fly over London without donning special flying kit. Avro's manager G. L. P. Henderson made many charter flights in it including return trips to Aintree on July 8 and Brighton on July 13. Its one recorded overseas flight took place in the early hours of September 6 when Capt. R. T. Fagan flew nonstop from Hounslow to Le Bourget in 2 hours 45 minutes with Norwegian passengers Robshon and Waase.
  Many hours were flown during the railway strike, by which time the permanent marking G-EACX had been applied but the C. of A. was not renewed in 1920, no doubt due to the very cramped accommodation of such a primitive conversion. When the Japanese acquired 504K manufacturing rights in 1921, they quickly produced a 504M equivalent known as the Aiba Tsubami IV with 150 h.p. Gasden Jimpu engine, one example of which, J-BABC, was still in use in 1928.

  Manufacturer: A. V. Roe and Co. Ltd., Hamble Aerodrome, near Southampton, Hants.
  Power Plant: One 100 h.p. Gnome Monosoupape
   Span 36 ft. 0 in. Length 29 ft. 5 in.
   Height 10 ft. 5 in. Wing area 330 sq. ft.
   Weights: Tare weight 1,220 lb. All-up weight 1,975 lb.
   Maximum speed 98 m.p.h. Cruising speed 85 m.p.h.
   Climb to 8,000 ft. 5-5 min. Endurance 3 hours
  Production: One aircraft only, K-134/G-EACX, c/n A.T.C.10; sole owner A. V. Roe and Co. Ltd.; C. of A. issued 25.6.19, not renewed in 1920
The prototype Avro 504 at Hendon, September 1913, in its original form with square cut engine cowling and warping 'ailerons'.
4034, a production Avro 504A.
Production Avro 504B serial 1032, with cut-away cockpit sides and tail skid pylon.
A R.N.A.S. anti-Zeppelin Avro 504C.
Avro 504J C4451 on which H.R.H. Prince Albert learned to fly, showing the characteristic lobed cowling.
Avro 504K F2623 during a postwar instructional flight over Salisbury Plain.
Avro 504J B.3103 of the C.F.S. Communication Flight al Lopscombe Corner, Salisbury, in 1918 with modified undercarriage.
The Avro 540, a postwar gunnery trainer version of the Avro 504K.
F8940, one of the Avro 504Ks modified at the R.A.E., Farnborough, in 1922 for low speed lateral control tests.
The Golden Age of barnstorming - Martin Hearn riding the top wing of Aviation Tours' Avro 504K G-EBYW circa 1933.
The Navarro Aviation Co.'s Avro 504K D9304 G-EAF.A joyriding at Whitstable, Kent in 1919. Like so many contemporary civil aeroplanes, it flew in drab military green with R.A.F. serial.
Avro Transport Company joyriding 504K E4359 JG-EABJ, Fleet No. 3, on the beach at Blackpool in 1919.
G-EAGI, one of the Central Aircraft Co.'s Northolt-based instructional 504Ks, retained the Vee-type undercarriage of the Home Defence fighter version.
For over a decade three of the greatest names in joyriding were those of Surrey Flying Services Ltd., the Cornwall Aviation Co. Ltd. and the Brooklands School of Flying Ltd., represented here by G-EBDP (1922-1930); G-EBIZ (1924-1935); and G-AAEM (1929-1931).
The Dyak engined 504K c/n D.l (later G-AUBG), built at Mascot by A.A.E.C. Ltd. from imported parts in 1920.
The special Avro 504K with modified undercarriage and tail assembly, believed G-AUDM, showing the revised side cowlings of later Dyak powered machines.
Danish Navy Avro 504K H2023/104 at Kastrup in 1923.
Det Danske Luftfartselskab's first Avro 504K G-EAJE in Danish marks as T-DOLM in 1921.
The Finnish Air Force ski-equipped Avro 504K AV-57 was supplied by the Aircraft Disposal Co. Ltd. in 1926 as G-EBNU (visible under lower mainplane).
201, first of the 1929 N.Z.P.A.F. Avro 504Ks, after being converted to ZK-ACN in 1931 and repaired with the wings of 206/ZK-ACS.
The Avro 504K 29 at Manchester prior to delivery to the Portuguese Government in May 1925.
N-37, the Avro 504K filled with 140 h.p. Hispano-Suiza HS 8Aa and cabin top for Lt. Christian Hellesen in 1929.
The Avro 504M three seat cabin machine K-134/G-EACX at Hendon in July 1919.
The prototype Avro 504L two seater C4329 on the beach at Hamble early in 1919, showing the original four-strut undercarriage.
K-144, F-EAFB, first of the Kaslbourne Aviation Co. Ltd.'s joyriding 504Ls (three individual cockpits), taxying out at Hove, Sussex, in August 1920.
Canadian Air Board forestry patrol Avro 504L G-CYAX, showing the revised undercarriage strutting used on the majority of conversions.
Avro 504A
Avro 508

  The Avro 508 was a two seat reconnaissance biplane built at the Manchester works in December 1913 and delivered at Brooklands for erection and test a month later. Following contemporary practice it was a twin boom, three bay pusher biplane of fabric covered wooden construction having equal span mainplanes structurally similar to those of the Avro 504 prototype. A wide centre section carried the first pair of interplane struts at its extremities, the dihedral commencing at this point as on the Avro 503. Ailerons were used for lateral control and the machine was noteworthy as the first Avro type to have aileron cables located inside the wing leading edge and running over buried pulleys.
  A capacious square-section nacelle, built up from four ash longerons and spruce cross struts, accommodated two crew in tandem. The observer/gunner sat in the nose for maximum field of vision with the pilot behind. Fuel and oil tanks were located behind the pilot's seat and just ahead of an 80 h.p. Gnome rotary engine mounted on steel tube bearers. The use of standard Avro cowlings and centre skid undercarriage heightened its likeness to a back-to-front Avro 504. Tail booms were of steel tubing braced by streamline section spruce struts, the rear extremities of which were built into the tailplane structure. For ease of dismantling, the booms were jointed just ahead of the tailplane leading edge. The rudder was an elongated version of the famous comma type, somewhat like an artist's palette.
  The Avro 508 was not adopted for the Royal Flying Corps and the single machine built made but two public appearances. The airframe was shown without covering at an exhibition at Belle Vue Gardens, Manchester on January 1-3, 1914 and the complete aircraft was shown on the Avro stand at the Olympia Aero Show, London on March 16-25,1914.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plant: One 80 h.p. Gnome
   Span 44 ft. 0 in. Length 26 ft. 9 in.
   Height 10 ft. 0 in. Wing area 468 sq. ft.
  Weights: Tare weight 1,000 lb. All-up weight 1,680 lb.
  Performance: Maximum speed 65 m.p.h. Endurance 4 1/2 hours
The Avro 508 reconnaissance pusher at the Olympia Aero Show, London, in March 1914.
Avro 510

  The Avro 510 was a large two seat, two bay seaplane built for the 1914 Circuit of Britain Race. A larger version of the 504 rudder proclaimed the aircraft's Avro origins but it bore no other resemblance to any previous machine built by the firm. The upper mainplane overhung the lower by more than 12 ft. and the extension planes (which carried the ailerons), were braced by cables to steel tube kingposts. Power was derived from a 150 h.p. Sunbeam eight cylinder watercooled engine (later named the Nubian), fitted with nose radiator and stub exhausts.
  The undercarriage consisted of four steel struts connected at their lower extremities to a tubular steel rectangle, the corners of which were bolted to the attachment points of each float. These were of entirely new design with a pronounced taper aft of the single step. The tail was supported on a large wooden float with water rudder.
  Built at Manchester in July 1914, the Avro 510 was despatched by rail to Calshot, starting point of the race. Following by road to supervise its erection, A. V. Roe put up for the night at Havant where the next morning he learned of England's declaration of war on Germany. The race was perforce cancelled but the Avro 510 was erected and flew well, the new float design being particularly successful. Much smoother landings were possible than with the old flat backed pontoon-type floats.
  When the trials were complete, the machine was purchased by the Admiralty and much to A. V. Roe's surprise a cheque was handed over on the spot by Capt. (later Air Vice Marshal Sir Arthur) Longmore. The Admiralty also placed an order for five production Avro 510s but stipulated a taller undercarriage incorporating an extra inclined strut and using the well-tried, but entirely outmoded, flat backed floats. These were bolted direct to the struts without the complicated sub-frame of the original. To A. V. Roe's disappointment the modern floats of the prototype were also replaced.
  R.N.A.S. Avro 510s were fitted with a fixed fin having a curved trailing edge which fitted snugly round the leading edge of the rudder. All six were based at Calshot and all were powered by the 150 h.p. Sunbeam. Data was published for a version with the 160 h.p. Gnome rotary but there is no evidence that this motor was ever fitted to an Avro 510. The Service history of the type is obscure but it is known that 130 was in service at Calshot until September 1917, and that 131 remained there in June 1916 while the remaining Avro 510s went to the Supermarine Works at Woolston for modification.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester
  Power Plants:
   One 150 h.p. Sunbeam Nubian
   One 160 h.p. Gnome
   Span (upper) 63 ft. 0 in. (lower) 38 ft. 0 in.
   Length (Sunbeam) 38 ft. 0 in. (Gnome) 37 ft. 6 in.
   Wing area 564 sq. ft.
   (Sunbeam) Tare weight 2,080 lb. All-up weight 2,800 lb.
   (Gnome) Tare weight 2,005 lb. All-up weight 2,790 lb.
   Maximum speed 70 m.p.h.
   Climb to 1,000 ft. 44 minutes. Endurance 4 1/2 hours
  Production: Prototype sold to the Admiralty 1914 and numbered 881; 130-134 built under Contract C.P.30654/14
One of the five production-type Avro 510s built for the R.N.A.S.
Avro 511

  Three full sized aircraft shown on the Avro stand at the Olympia Aero Show, London, March 16-25, 1914 were a production Avro 504 seaplane, the Avro 508 pusher and the Avro 511 single seat, single bay biplane. This was designed specifically for fast scouting in the event of war and could be swiftly dismantled for road transport to the operational area. Heavily staggered, sparless mainplanes of cellular construction, designed and stressed by Avro's assistant designer H. E. Broadsmith, were given pronounced sweepback in an attempt to reduce the span and attain inherent stability. On this account the aircraft was promptly and unofficially dubbed "Arrowplane" or even "Arrowscout" by the sensational press but these names can find no place in a serious work of reference. Ailerons were fitted to all four wings and single wide chord interplane struts were used on each side. Landing flaps were incorporated in the inboard trailing edges of the lower mainplanes and pivoted diagonally about a stout steel tube which passed through the fuselage. This device, years ahead of its time, reduced touchdown speed to 35 m.p.h.
  The Avro 511 was otherwise typically Avro with standard centre-skid undercarriage and comma-type rudder. The nose was of good streamline shape with a close fitting cowling round the 80 h.p. Gnome Monosoupape rotary engine. The cowling was later modified as it prevented adequate cooling. Estimated maximum speed was 95-100 m.p.h. and the machine was to have been piloted by F. P. Raynham in the Aerial Derby Race round London on May 23, 1914 (racing No. 14). Storms on the eve of the race caused deterioration in the weather which led to a postponement until June 6 but Raynham managed to make one or two demonstration runs for the benefit of the few hardy spectators. When returning home on the following day he made a safe landing after the engine failed within gliding distance of Brooklands. It had not proved as fast as had been hoped but was nevertheless entered (racing No. 20) in the postponed Aerial Derby.
  In preparation for this event the Avro 511 was fitted with alternative mainplanes without sweepback which Broadsmith had designed in case trouble was encountered with the swept wings. The rebuilt machine, designated Avro 514, was also equipped with a light weight, unsprung, Vee-type racing undercarriage without the familiar skid, but while taxying out at Brooklands to take off for Hendon on the eve of the race, an eye bolt sheared. The undercarriage collapsed, breaking the airscrew and bending the engine crankshaft as well as damaging wings and fuselage. After reconstruction at Manchester the Avro 514 was successfully flown from Southport Sands by F. P. Raynham in July 1914 but further development was ended by the outbreak of war.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plant: One 80 h.p. Gnome Monosoupape
   Span 26 ft. 0 in. Length 22 ft. 4 in.
   Height 9 ft. 4 in. Wing area 235 sq. ft.
  Weights: Tare weight 675 lb. All-up weight 1,165 lb.
  Performance: Maximum speed 95-100 m.p.h.
Avro 521

  Designed late in 1915, the Avro 521 two seat fighter-trainer was a hybrid embodying the features of several Avro 504 variants. In side elevation the straight top longerons proclaimed it a derivative of the 504 prototype, yet the short span ailerons and the rudder/tail skid assembly were pure 504A, the cockpit positioning and centre section struts were 504E, the Vee strut undercarriage was contributed by the 504G and the streamlined headrest was copied from the Avro 519. Standard Avro 504 mainplanes were shortened to a span of approximately 27 ft. 6 in., cut away at all four wing roots to improve upward and downward vision and rigged with only a single set of interplane struts on each side. The engine was a 110 h.p. Clerget rotary in characteristic Avro cowlings.
  The initial order was for one machine, test flown at Trafford Park, Manchester by F. P. Raynham with H. E. Broadsmith standing up in the rear cockpit and brandishing a dummy machine gun to enable the effect of the extra drag to be assessed. Raynham found the Avro 521 longitudinally unstable and unpleasant to fly; nevertheless it was delivered to Farnborough in February 1916 and 25 production machines were ordered for the R.F.C.
  Proposals were also made for interchangeable wings to suit different roles but it is not known if any aircraft were actually modified. Designation Avro 521A was allotted to a version with mainplanes of 46 ft. span, while with standard Avro 504 mainplanes of 36 ft. span it was to have been known as the Avro 521B. It is doubtful if all were completed and there is no record of any production Avro 521 having been delivered. This strengthens the belief that the Avro 521 in which Capt. Garnett crashed and was killed at Gosport in 1917 must have been the prototype.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester
  Power Plant: One 110 h.p. Clerget
  Production: One unmarked prototype Works Order number believed 1811; and twenty-five production aircraft 7520 to 7544, believed not all built
  Service Use: At the Advanced Training School, Gosport, Hants.
Avro Type 519

  The Avro Type 519 appears to have been a contemporary of the Grahame-White Type 18 and, like that aeroplane, very little is known about it. By a process of elimination, it seems certain that the Type 519 was intended as a possible bomber, and was evidently an attempt to adapt the Avro Type 510 'Round Britain' racing seaplane of 1914 for military consideration. (Although the 1914 race had been cancelled on the outbreak of war, the Admiralty had purchased the prototype and five further examples.)
  The Type 519 retained the earlier aircraft's 150hp Sunbeam Nubian watercooled engine as well as similar two-bay wings of unequal span. The fuselage was generally similar, but was faired to incorporate curved upper decking and raised headrest fairings aft of the cockpits. The wheel-and-skid undercarriage with oleo struts was reminiscent of that on the Avro 504. In order to meet naval storage requirements, provision was made to fold the wings.
  The design drawings, prepared by Roy Chadwick and H E Broadsmith, met with interest at the Admiralty and War Office to the extent that Avro received orders for four aircraft - two single-seat Type 519s for the RNAS and two two-seat Type 519As for the RFC; the latter featured fixed wings and a plain V-strut undercarriage without the central skid.
  All four aircraft are believed to have been delivered to Farnborough by May 1916 for trials, but it is said that they did not meet the Service strength requirements with the Nubian engine, and their ultimate fate is not known.

  Type: Single-engine, single- and two-seat, two-bay biplane (probably intended as experimental bomber).
  Manufacturer: A Y Roe & Co Ltd, Miles Platting, Manchester.
  Powerplant: One 150hp Sunbeam Nubian eight-cylinder, water-cooled, in-line engine driving two-blade propeller.
  Dimensions: Span (Type 510), 63ft 0in.
  Performance: Max speed, approx 76 mph at sea level.
  Armament: No gun armament; provision for bomb load, unknown.
  Prototypes: Four; two Type 519s for Admiralty, Nos 8440 and 8441, and two Type 519As for War Office, Nos 1614 and 1615.
8441, second of the two R.N.A.S. Avro 519 single seat biplanes.
1614, first of the two R.F.C. Avro 519A two seaters.
Avro 527 and Avro 528

  While the Avro 523 Pike was under construction in the Manchester works, A. V. Roe and Co. Ltd. were also building a modified, two seat version of the Avro 504G for the Royal Flying Corps. It was fitted with a 150 h.p. Sunbeam engine and a standard central skid undercarriage but retained the fixed fin normally fitted only to R.N.A.S. machines. The mainplanes were standard Avro 504K units of 36 ft. span with which it was designated Avro 527, and a second version with a span of 42 ft. was also considered under the designation Avro 527A.
  The machine was not a success, the rate of climb was poor, and as on the Avro 519 the radiator and twin exhaust stacks seriously obstructed the pilot's forward view.
  Type number Avro 528 was given to a similar but more powerful aeroplane ordered by the Admiralty and fitted with a 225 h.p. Sunbeam engine. This machine followed the Avro 523A Pike through the works in July-August 1916 but no other information concerning it or the Avro 527 has survived.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 527 and 527A) One 150 h.p. Sunbeam
   (Avro 528) One 225 h.p. Sunbeam
   (Avro 527) Span 36 ft. 0 in. (Avro 527A) Span 42 ft. 0 in.
   (Avro 528) Span (upper) 65 ft. 0 in. (lower) 55 ft. 0 in.
   (Avro 527) One aircraft only to Works Order 2100
   (Avro 528) One aircraft only to Works Order 2350
Avro 528
Avro 523 Pike

  In 1916 A. V. Roe decided to move the Avro factory from Manchester to a waterside site convenient for the development of naval aircraft, and bought the stretch of Hampshire grassland which is now Hamble Aerodrome, together with a mile of foreshore on the adjacent Southampton Water. Manchester architect Harry Fairhurst designed the new Avro Hamble Works and a garden city of 350 houses for employees, but after the hangars and only 24 houses had been built, wartime shortage of building materials halted the scheme. Very reluctantly the company was compelled to keep its main works in Manchester and to use Hamble only for erection and as an experimental establishment.
  It was to Hamble therefore that their first twin engined machine and the first to receive a type name, the Avro 523 Pike, was sent for erection and test in May 1916. Designed by Roy Chadwick to R.A.F. Types IV, VI and VII as a long distance photo-reconnaissance fighter or short range day or night bomber, it was powered by two opposite handed 160 h.p. Sunbeam engines driving pusher airscrews. A fine example of advanced thinking, the Pike was a large three-bay biplane equipped with horizontal-tier bomb-stowage (designed personally by A. V. Roe) and carrying the pilot just ahead of the mainplanes. Gunners' cockpits fore and aft were armed with Lewis guns on rotatable ring mountings. The divided undercarriage was sprung with larger editions of the famous Avro shock absorbers, and a large comma-type rudder was hinged to a fixed fin of low aspect ratio.
  Although performance on a mere 320 h.p. was said to be very good, the Pike appeared too late. Production contracts had already been awarded to Short Bros, for a standard R.N.A.S. bomber, and the R.F.C. was interested solely in the much larger Handley Page heavy bombers then under construction.
  The Pike prototype was sent to the R.N.A.S. experimental establishment on the Isle of Grain for test before Admiralty officials but during one test flight the Pike was flown with the C.G. position too far aft and was so tail heavy that F. P. Raynham dared not throttle back to attempt a landing. The situation was saved through the gallantry of R. H. Dobson (later Sir Roy Dobson), who climbed out of the rear cockpit and along the top of the fuselage to transfer his weight to the bow gunner's position. The danger of stalling was averted and a successful landing made.
  A second machine, the Avro 523A, tested at Hamble in August 1916, differed from the earlier machine only in the engine installation. It was fitted with two 150 h.p. Green engines mounted on revised strutting and driving tractor airscrews. Whereas the original Pike employed nose radiators on each nacelle, the Green engines of the 523A were cooled by rear mounted radiators. At the completion of official tests both machines were returned to the manufacturers to enjoy extensive experimental careers and were still in commission at Hamble in 1918. Plans to produce Avro 523B and 523C variants with higher powered Sunbeam and Rolls-Royce engines were shelved, but the Admiralty ordered an improved version which appeared in 1917 as the Avro 529.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 523) Two 160 h.p. Sunbeam
   (Avro 523A) Two 150 h.p. Green
   Span 60 ft. 0 in. Length 39 ft. 1 in.
   Height 11 ft. 8 in. Wing area 815 sq. ft.
   Weights: (Avro 523) Tare weight 4,000 lb. All-up weight 6,064 lb.
  Performance: (Avro 523)
   Maximum speed 97 m.p.h.
   Climb to 5,000 ft. 9 min. 30 sec.
   Endurance 7 hours
   (Avro 523) One aircraft only, Works Order number believed 2230
   (Avro 523A) One aircraft only, Works Order number believed 2231

Avro 529

  In 1916 the Admiralty ordered two enlarged versions of the Pike for long range bombing duties. Unnamed and known only as the Avro 529 and 529A, they had three-bay folding wings rigged without dihedral, and although closely resembling the Pike were distinguishable from it by the rudder shape. That of the Pike was flat topped with a straight bottom edge to the balance portion, but those of the Avro 529s were curved with a semi-circular balance area.
  Whereas the first aircraft was built wholly in Manchester and assembled at Hamble, the second was sent there in unfinished state to make way for increased Avro 504K production at Manchester. The Avro 529, first flown in April 1917, was powered by uncowled 190 h.p. Rolls-Royce Falcons mounted at mid-gap and driving opposite handed airscrews. The Avro 529A, flown at Hamble in the following October, had two 230 h.p. Galloway-built B.H.P. engines which were fully cowled and housed in nacelles on the lower mainplane. Radically different installations called for two distinct types of fuel systems and in the Avro 529 petrol was carried in a 140 gallon tank in the centre fuselage. On the Avro 529A each nacelle carried its own 60 gallon supply with small wind-driven pumps to raise the fuel to a 10 gallon gravity tank above the engine.
  Lewis guns were mounted on Scarff rings over front and rear cockpits and the rear gunner was provided with emergency dual control. The front gunner also acted as bomb aimer and steered the pilot on to target with the aid of a Gosport speaking tube. On the 529A, which carried twenty 50 lb. bombs stowed nose upwards inside the fuselage between the spars of the lower wing, he was able to use a projecting prone position in the cockpit floor.
  Apart from poor elevator control (a shortcoming of both types), the performance of the Avro 529A was very good on such low power, asymmetrical flying being particularly easy. Nevertheless no production contract materialised and only the prototypes were built.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 529) Two 190 h.p. Rolls-Royce Falcon
   (Avro 529A) Two 230 h.p. B.H.P. (Galloway-built)

Dimensions, Weights and Performances:
   Avro 529 Avro 529A
Span 63 ft. 0 in. 64 ft. 1 in.
Length 39 ft. 8 in. 39 ft. 8 in.
Height 13 ft. 0 in. 13 ft. 0 in.
Wing area 922 1/2 sq. ft. 910 sq. ft.
Tare weight 4,736 lb. 4,361 lb.
All-up weight 6,309 lb. 7,135 lb.
Maximum speed 95 m.p.h. 116 m.p.h.
  to 5,000 ft. - 7 min. 0 sec.
  to 6,500 ft. 11 min. 25 sec. -
Ceiling 13,500 ft. 17,500 ft.
Endurance 5 hours 5 hours 15 min.

  Production: Prototypes only under Contract CP. 122495/16 with R.F.C. serials 3694 (Avro 529) and 3695 (Avro 529A)
The Avro 523A with two 150 h.p. Green engines and tractor airscrews, at Hamble 1916 with the Pike.
3694, the sole Avro 529, at Hamble in April 1917.
3695, the Avro 529A, identified by low set nacelles.
Avro 523 Pike
Avro 530

  The Avro 530, first flown in July 1917, was a two seat fighter which failed to secure a production contract in the face of competition from the celebrated Bristol Fighter because of non-availability of engines. The 300 h.p. watercooled Hispano-Suiza was not obtainable when required and the machine flew with a 200 h.p. Hispano-Suiza. Even on the lower power the performance of the Avro 530 rivalled that of the Bristol and it might still have become one of the famous fighters of the First World War had not almost all 200 h.p. Hispano-Suiza engines been earmarked for the S.E.5A.
  Built at Manchester and erected and flown at Hamble, the Avro 530 was an unusually clean two bay biplane with a tail unit resembling that of the first Pike. Its unusually deep fuselage was of wire braced, box-girder construction with the fabric covering stretched over formers to give a more streamlined shape. The engine mounting consisted of strutted duralumin girders. The pilot occupied the front cockpit but the fuselage was so deep at this point that it almost filled the mainplane gap, leaving only enough room for a single Vickers gun in a plywood fairing on top of the fuselage. The top wing was thus on a level with the pilot's eyes, ensuring adequate view in all upward and forward directions while a rear gunner armed with a single Lewis gun on a Scarff mounting commanded the downward and rearward view.
  The fabric covered, wooden mainplanes were of R.A.F. 14 section and engine cooling was by means of a large frontal radiator. In the original form of the machine the lines of the short, blunt nose were improved by fitting a hollow, open-fronted metal spinner. The famous Avro skid-type undercarriage gave place to a new low-drag unit comprising two narrow Vees faired with metal sheeting and braced by an internal Vee strut. Landing speed was reduced by trailing edge flaps actuated by a handwheel in the pilot's cockpit. They were fitted to both upper and lower mainplanes between the inboard ends of the ailerons and the fuselage.
  In an attempt to solve the engine supply problem, the Avro 530 was afterwards re-engined with a 200 h.p. Sunbeam Arab and modified in various ways. An unfaired, wide angle Vee undercarriage was fitted; there was no spinner; the tail fin was larger and more gracefully curved; and new R.A.F.15 section mainplanes were fitted. These were without flaps but had long-span ailerons and metal cuffs to fair the ends of the interplane struts into the wing.
  In view of its deep and capacious fuselage, the Avro 530 was offered in 1920 as a high speed touring aeroplane with comfortable tandem cockpits above a large baggage compartment. There is no evidence that this modification took place and the machine did not receive a civil registration.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants
   One 200 h.p. Hispano-Suiza
   One 200 h.p. Sunbeam Arab
   Span 36 ft. 0 in. Length 28 ft. 6 in.
   Height 9 ft. 7 in. Wing area 325+ sq. ft.
   Tare weight 1,695 lb. (1,760 lb.)
   All-up weight 2,680 lb. (2,500 lb.)
   Maximum speed 114 m.p.h. (118 m.p.h.)
   Cruising speed 95 m.p.h. (102 m.p.h.)
   Climb to 5,000 ft. 6 min. 30 sec. (5 min. 30 sec.)
   Ceiling 18,000 ft. Endurance 4 hours
  Production: One prototype only, to Contract A.S.425 17 C, Works Order number believed 3800

  Note - Estimated figures for proposed civil version in parentheses.
The Avro 530 with 200 h.p. Sunbeam Arab, enlarged fin and flap-less mainplanes.
Avro 533 Manchester

  The Manchester of 1918, final variation on the Pike/Avro 529 theme, was a three seat, twin engined bomber or photo reconnaissance fighter designed to Air Ministry requirements round two of the new 320 h.p. A.B.C. Dragonfly I seven cylinder radial engines. Unlike its forebears the Manchester was constructed entirely at Hamble and its deeper, more shapely fuselage giving improved crew accommodation was but one of many refinements, others including a graceful (almost de Havilland-shaped) rudder, and ailerons balanced by means of 'park bench' auxiliary aerofoils.
  Erection of the first Manchester was completed by October 1918 after which it was dismantled for covering, during which the opportunity was taken to fit two 300 h.p. Siddeley Puma high compression, watercooled engines. This was to prevent interruption of flight tests by the non-delivery of the Dragonfly engines which had run into a number of teething troubles. The Pumas arrived at Hamble in November, and thus powered, the aircraft was known as the Avro 533A Manchester Mk. II. First flights took place early in December 1918 and the Mk. II aircraft F3492 consequently had an earlier serial than the Mk. I which followed. On December 20 F3492 went to No. 186 Development Squadron, Gosport, where it remained until at least January 9, 1919 before proceeding to Martlesham in the following March. Official trials lasted until September 1919 when F3492 returned to Hamble to be fitted with Napier Lions, a project which did not materialise.
  Delivery of the Dragonfly engines in December 1919 enabled the second airframe F3493 to be completed as the Manchester Mk. I. After prolonged manufacturer's tests it was flown from Hamble to Martlesham for official trials in October 1919, the journey via Winchester, Basingstoke, London and Chelmsford occupying 90 minutes.
  Apart from the engines and the revised nacelle shape of the Mk. I which decreased the effective area of the lower wing by 4 sq. ft., the two marks of Manchester differed only in their tail units. Both had balanced rudders but all tail surface areas were greater in the Mk. I which had taller vertical surfaces and an unbalanced elevator. That of the Mk. II was horn balanced.
  The performance of both marks was quite remarkable on comparatively low power and despite their size could be looped and spun, but the need for a bomber of this type disappeared when the war ended. A third airframe, intended as the Manchester III with two 400 h.p. Liberty engines, was completed but the engines were never fitted. The jigs were then dismantled and A. V. Roe's war effort was at an end.

  Manufacturers: A. V. Roe and Co. Ltd., Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Mk. I) Two 320 h.p. A.B.C. Dragonfly I
   (Mk. II) Two 300 h.p. Siddeley Puma high compression
   (Mk. III) Two 400 h.p. Liberty 12
   Span 60 ft. 0 in. Length 37 ft. 0 in. Height 12 ft. 6 in.
   Wing area (Mk. I) 813 sq. ft. (Mk. II) 817 sq. ft.
   (Mk. I) Tare weight 4,887 lb. All-up weight 7,390 lb.
   (Mk. II) Tare weight 4,574 lb. All-up weight 7,158 lb.
   (Mk. I) Maximum speed 112 m.p.h.
   Climb to 10,000 ft. 14 min. 20 sec.
   Ceiling 19,000 ft. Endurance 5 | hours
   (Mk. II) Maximum speed 119 m.p.h.
   Climb to 10,000 ft. 16 min. 30 sec.
   Ceiling 17,000 ft. Endurance 3$ hours
   F3492 (Manchester Mk. II); F3493 (Manchester Mk. I);
   F3494 (Manchester Mk. III) airframe only
Avro 531 Spider

  First flown at Hamble in April 1918, the Spider was an unsponsored private venture single seat fighter in which many Avro 504K components were used for speed of manufacture. To this end a shortened rear fuselage of conventional construction with spruce longerons was married to a standard Avro 504K front fuselage and the engine was a' borrowed' 110 h.p. Le Rhone. There seems little doubt that the Avro company hoped that the Spider would replace the single seat Avro 504K night fighter in the Home Defence Squadrons. To simplify rigging (a time consuming operation not acceptable to squadrons in the field) all flying and landing wires were replaced by very rigid welded steel Warren girder interplane bracing. This comprised six faired steel tubes arranged in three inverted triangles on each side, anchored to the main spars of the upper mainplane and to the front spar of the lower. Ailerons were fitted only to the upper wing, the lower being shorter and with a chord of only 2 ft. 6 in.
  The simple steel Vee strut undercarriage was reminiscent of the Avro 530 in modified form and the attempt made in the earlier design to improve substantially the pilot's field of vision was carried a stage further in the Spider by siting the cockpit under a circular aperture in the centre section. This was mounted close to the fuselage so that the pilot's head protruded above it. Armament consisted of a single synchronised Vickers gun on top of the fuselage and slightly to starboard of centre.
  The little fighter was a delight to handle, with powerful and well harmonized controls which made it extremely manoeuvrable, and more than a match for many of its contemporaries. Performance was further enhanced by fitting a 130 h.p. Clerget and drawings were made for the installation of a 150 h.p. Bentley B.R.I rotary or a 170 h.p. A.B.C. Wasp I radial. Well-known pilots were invited to fly it in off duty hours and to give their opinions, for which purpose it was at the School of Special Flying, Gosport, from April 27 to May 18, 1918 and again on July 13. In this way the Spider became such a topic of conversation that the Air Ministry could not fail to take note of it. Nevertheless it was not ordered into production because the Sopwith Snipe had already been standardised as the R.A.F.'s next single seat fighter. The Spider was therefore used for experimental work which included benzole fuel tests at Alexandra Park in August 1919.
  A considerably modified version of the Spider was allotted type number Avro 531 A. This had conventional two-bay, wire braced mainplanes rigged with a considerable stagger and using 504K-type interplane struts. With the 130 h.p. Clerget rotary the Avro 531A had a performance similar to that of the Spider. Serial allocation suggests that construction of only one Avro 531 and one Avro 531A was undertaken. There is no means of proving that the latter ever existed as such and it is probable that that machine donated its fuselage, undercarriage and tail unit to the civil Avro 538, and first flew in this form.
  The Avro 538 emerged from the flight shed at Alexandra Park, Manchester, in May 1919 registered K-132, a temporary civil marking later changed to G-EACR. As far as is known these symbols were never carried and the machine's main adornment was the word AVRO in the usual enormous black letters. Although powered by a 150 h.p. Bentley B.R.I and intended as a racer, a main spar defect limited the machine's activities to straight and level flight, and a notice to this effect was displayed in the cockpit. Bearing fleet number 7, the Avro 538 was used solely by the Avro Transport Company's chief engineer J. C. C. Taylor, who flew it around the joyriding sites in order to sign out the Avro 504Ks.

  Manufacturers: A. V. Roe and Co. Ltd., Clifton Street, Miles Platting, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 531)
   One 110 h.p. Le Rhone
   One 130 h.p. Clerget
   (Avro 531 A) One 130 h.p. Clerget
   (Avro 538) One 150 h.p. Bentley B.R.I

Dimensions, Weights and Performances:
   Avro 531 Spider Avro 531A Avro 538
   Clerget *Bentley Clerget Bentley
Span (upper) 28 ft. 6 in. 28 ft. 6 in. 28 ft. 0 in. 28 ft. 0 in.
Span (lower) 21 ft. 6 in. 21 ft. 6 in. 27 ft. 0 in. 28 ft. 0 in.
Length 20 ft. 6 in. 20 ft. 6 in. 20 ft. 6 in. 20 ft. 6 in.
Height 7 ft. 10 in. 7 ft. 10 in. 8 ft. 6 in. 8 ft. 6 in.
Wing area 189 sq. ft. 189 sq. ft. - 210 sq. ft.
Tare weight 963 lb. 1,148 lb. 960 lb. 975 lb.
All-up weight 1,517 lb. 1,734 1b. 1,514 1b. 1,400 1b.
Maximum speed 120 m.p.h. 124 m.p.h. 120 m.p.h. 125 m.p.h.**
   to 3,500 ft. - 2 min. 12 sec. - -
   to 5,000 ft. 4 min. 0 sec. - 4 min. 0 sec. 4 min. 0 sec.
   to 10,000 ft. - - - 10 min. 0 sec.
Ceiling 19,000 ft. - 19,000 ft. -
Endurance/Range - 2 1/2 hours 3 hours 320 miles
*Estimated figures. **Cruising speed 108 m.p.h.

   (Avro 531 and 531 A) Serial allocation B3952 and B3953;
   (Avro 538) One aircraft only, K-132/G-EACR, c/n 538/1, registered to A. V. Roe and Co. Ltd. 25.5.19, s.o.r.* 9.20
*Abbreviation used throughout to indicate 'struck off register'.
Avro 531 Spider
Avro 536

  Reference has been made in previous chapters to a unique batch of civil aircraft built in the Hamble works between April and November 1919. To satisfy the enormous demand for pleasure flights, the Avro Transport Company simply had to provide more seats and quickly. The problem was solved by giving some of these Hamble 504K variants a nine inch increase in width to enable four passengers to sit in side by side pairs in the rear cockpit. Each occupant had his own individual windscreen, the rear windscreens being fixed to a strip of decking hinged to the starboard top longeron for ease of entry. In this form, as the Avro 536, the machine was a short range five seater and (as in the case of Avro 504Ls from the same production batch), extra take-off power at the higher all-up weight was given by a 150 h.p. Bentley B.R.I.
  The Avro 536 was easily distinguishable from the 504K since the extra nine inches of width resulted in an obvious difference in the spacing of the centre section struts. Sporting a tricolour rudder, but no other markings apart from AVRO in large white letters, the prototype first flew at Hamble in April 1919 one of the first passengers being the Lord Chancellor who flew in it with H. A. Hamersley on the 25th of that month. Eight production 536s which followed plunged immediately into the fray at southern joyriding sites: K-104 to K-106 at Hounslow Heath; K-l 16 and K-l37 at Southsea; K-161 at Weston-super-Mare; and K-166 at Margate. K-165 is believed to be that sent to the First Air Traffic Exhibition at Amsterdam. A batch of 12 was also put in hand at Manchester but only seven of these were certificated in time to earn money in 1919. Whereas the constructor's numbers of the Hamble batch were prefixed A.T.C, (Avro Transport Company), those built in Manchester were initialled B for Blackpool where three pilots carried 500 passengers in 536s on the day of their introduction.
  All Avro 536s had the 504L-type fin to offset the torque of the powerful Bentley rotary except the first three production aircraft, two of which were involved in serious accidents. Capt. H. R. Hastings was killed when K-106 stalled on approaching to land at Sandhurst at the end of a charter flight from Hounslow on August 8, 1919; and Capt. E. A. Sullock, on direct track from Hounslow to Southend with two passengers on September 9, suffered engine failure over Rotherhithe and put K-104 down in Southwark Park where it broke its back. A third Avro pilot, Brig. Gen. C. F. Lee C.M.G., who had demonstrated the 504J C4312 at Washington in 1917, was killed when the fin-equipped K-161 stalled when coming in to land on Weston-super-Mare sands in the same month.
  Unlike other Avro 536s, the prototype boasted a large aerofoil shaped centre section fuel tank and after a few trial flights at Hamble, was fitted with floats and extended fin to become the sole 536 seaplane. It retained the tricolour rudder and on July 2, 1919 commenced a joyriding season in the Isle of Wight as K-114. The pilot was Capt. F. Warren Merriam who flew A. V. Roe daily to and from Hamble while he was on holiday in the island and, assisted by a 504L, completed a two months' lucrative season at Ryde, Sandown, Shanklin and Ventnor. The last two Hamble-built 536s were special aircraft; K-139 / G-EADV was a two seater with large fuselage fuel tank for experimental work or long distance competition flying, and the other (23rd and last machine on the mixed production line) was converted into a cabin type known as the Avro 546 for three passengers and pilot. Main differences between this aircraft and the contemporary Avro 504M lay in the widened fuselage, open pilot's cockpit, squarish windows below the top longeron and the Bentley B.R.I engine. Registered G-EAOM, the Avro 546 saw little service and only made a few flights at Hamble and West Blatchington Farm, Brighton, early in 1919-20.
  When the Avro Transport Company ceased operations a few of its former pilots hired 536s and carried on in 1920 but all eventually returned to Alexandra Park for storage. Four from the tail end of the production line (G-EAKM-'KP), completed too late to be used commercially, were also stored. In 1923 F. J. V. Holmes bought 'KN for use by Berkshire Aviation Tours Ltd. and in 1925 'KJ, 'KM and 'KP were acquired by Surrey Flying Services Ltd. to take over joyriding from their aged 504Ks.
  Bentley rotaries were no longer in service in 1925 and the Surrey Avro 536s were fitted with Clcrgets. With reduced fuel loads they were very economical indeed, carrying pilot and four passengers quite satisfactorily on the company's famous 5 minute/5 shilling 'flips'. Low power also made the dorsal fin unnecessary and in 1926-27 the firm erected four additional Avro 536s G-EBOF, 'OF, 'RB and 'TF, for which no original construction details were recorded. They were evidently the best of the other airframes still remaining at Alexandra Park (then in process of closing down) and the unexplained constructor's number P.8 given for G-EBOY was evidently a corruption of B.8, identifying it as the former G-EAKL. They seldom ventured far afield, although G-EBOY gave joy flights from the beach at Jersey in 1927 and during a barnstorming tour in 1928 'RB was used extensively for wing walking exhibitions.

  Manufacturers: A. V. Roe and Co. Ltd., Newton Heath, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 536)
   One 130 h.p. Clerget
   One 150 h.p. Bentley B.R.I
   (Avro 546)
   One 150 h.p. Bentley B.R.I
   Span 36 ft. 9 in.
   Length 29 ft. 5 in.
   Height 10 ft. 5 in.
   Wing area 335 sq. ft.
   Tare weight 1,431 lb.
   All-up weight 2,226 lb.
   Maximum speed 90 m.p.h.
   Cruising speed 70 m.p.h.
   Initial climb 550 ft./min.
   Ceiling 12,000 ft. Range 190 miles
Note: The above figures apply to both Avro 536 and 546.

  (a) Hamble built
   K-114 / G-EACC, c/n A.T.C.l, C. of A. 3.7.19, prototype flown as landplane 5.19 and as seaplane 7.19, s.o.r. 7.21
   A.T.C.2-A.T.C.9: K-104/G-EAAQ, C. of A. 14.5.19, crashed in South-wark Park, London 9.9.19; K-105/G-EAAP, C. of A. 14.5.19, crashed 12.19; K-106/G-EAAO, C. of A. 16.5.19, crashed at Sandhurst 6.8.19; K-137/ ' G-EADC, C. of A. 3.6.19, scrapped at Hamble 12.19; K-161/G-EAGM, C. of A. 12.7.19, crashed at Weston-super-Mare 1.9.19; K-165/G-EAHA, C. of A. 12.8.19, s.o.r. 9.20, believed in the Netherlands; K-166JG-EAHB, C. of A. 17.7.19, scrapped at Hamble 12.19; K-J16/G-EACG, C. of A. 17.6.19, crashed 12.19.
   A.T.C.11, K-139/G-EADV, experimental long range two seater, scrapped 12.19; A.T.C.23, G-EAOM, C. of A. 22.12.19, completed as Avro 546, s.o.r. 12.20
  (b) Manchester built
   c/n B.1-B.12: K-173/G-EAID, K-174JG-EAIE (Fleet No. 19), G-EAKD, K-175JG-EAIF and G-EAJR, all certificated 8.19, placed in storage at Alexandra Park 8.21; G-EAKJ, C. of A. 9.9.19, based at Brighton, to Surrey Flying Services Ltd. 4.24; G-EAKK, C. of A. 9.9.19 and G-EAKL, C. of A. 19.11.19, both stored at Alexandra Park 8.21; G-EAKM to Surrey Flying Services, C. of A. 18.8.25, crashed at Taplow, Bucks. 6.7.28; G-EAKN to F. J. V. Holmes, C. of A. 17.4.24, crashed 1.9.24; G-EAKO stored at Alexandra Park 8.21; G-EAKP to Surrey Flying Services Ltd., C. of A. 15.7.25
  (c) Erected by Surrey Flying Services Ltd., Croydon
   G-EBOF, C. of A. 26.6.26; G-EBOY, C. of A. 28.8.26; G-EBRB, C. of A. 13.5.27, crashed 12.6.28; G-EBTF, C. of A. 1.9.27. Surviving three s.o.r. 12.30
The prototype Avro 536 K-114 / G-EACC at Hamble in May 1919 in its original form without dorsal fin.
The prototype Avro 536 joyriding at Sandown, I.O.W., in seaplane form in July 1919, showing its unique aerofoil shaped centre section tank.
K-137 / G-EADC, a standard Avro Transport Company Avro 536 at Southsea in 1919.
Avro 534 Baby

  After the Armistice A. V. Roe was impatient to return to low powered flying and build a light aircraft of 600 lb. all-up weight with an engine of 20-30 h.p. which could disport itself within the confines of any large field. Chief designer Roy Chadwick favoured an aeroplane with a heavier wing loading, an engine of 40-50 h.p., and cross country capability. Final design was dictated by engine availability, the only suitable one in existence being A. V. Roe's 35 h.p. Green which had been preserved by Mr. Fred May of the Green Engine Co. Ltd. It is said that this engine was fitted originally to the first Avro Type D biplane for Pixton's flight to Brighton on May 6, 1911.
  The little Avro 534 was designed round this veteran power plant and although at first named the "Popular", soon acquired the type name Baby. The Green Engine Co. Ltd. completely modernised the engine and fitted aluminium pistons, new type camshaft, valve gear and oil pressure regulator. Cooling was by traditional nose radiator. The Baby was an equal span, single bay biplane of wire braced, fabric covered wooden construction with ailerons on all four wings and the balance area of the famous Avro comma rudder was increased slightly to make it an accurate circle. About a dozen of these machines were built singly at Hamble and eight of them helped to lay sure foundations for the light aeroplane movement which came seven years later. Their Green engines, even lighter than the remodelled original, were specially built by Peter Brotherhood Ltd. of Peterborough from a complete set of manufacturing drawings found in the Green Engine Company's archives.
  The prototype Baby emerged on April 30, 1919 and it is said that its total flying life of 2 minutes ended when H. A. Hamersley spun into the Hamble foreshore from 300 ft. when the ignition switches were cut inadvertently. The same pilot won the handicap section of the Aerial Derby at Hendon on June 21, 1919 at an average speed of 70-3 m.p.h. in K-131, usually regarded as the first Avro Baby. It certainly had the same engine but a number of minor differences identify it as actually the second machine of the type, first flown at Hamble May 10, 1919. As if to emphasise that the Baby was no low powered freak, Hamersley won the Victory Trophy Race at Hendon at 77 m.p.h. in July and flew nonstop from Hounslow Heath to Brussels in 2 hours 50 minutes in August, afterwards flying on to the First Air Traffic Exhibition at Amsterdam. The machine was dazzle painted and carried the words 'Avro Baby' in large white letters. The original marking K-131 remained, but for the overseas flight the permanent registration G-EACQ was painted in white on the sloping decking.
  On its return the elevator control system was modified so that cables previously carried within the fuselage now ran externally from double-ended cranks mounted on a cross shaft behind the pilot. The Baby then gave aerobatic displays along the South Coast to publicise the joyriding Avro 504Ks. Chadwick, who had just been taught to fly by Hamersley, frequently went cross country in it but when flying low on January 13, 1920 an abnormal bump deposited the aircraft on the ground in the garden of the Rev. Everard Verdon Roe's Hamble Vicarage. Chadwick was gravely injured and eyewitness accounts suggest that the Baby was a complete wreck and it is probable that the rebuilt aircraft incorporated only the engine and primary structure of the earlier machine. Registration G-EACQ was retained and many detail improvements were made. These included a raised tailplane; tapered ailerons; a slightly taller, oval shaped rudder; a new oil tank without projecting filler cap; more streamlined inter plane struts and the pitot head repositioned on the top wing. H. J. 'Bert' Hinkler bought it in April 1920 and on May 31 made a sensational 650 mile nonstop flight from Croydon to Turin in 9 1/2 hours for which he was later awarded the Britannia Trophy. He went on to Rome and flew back in easy stages3 reaching Hamble on June 10. The machine was then exhibited at the Olympia Aero Show and on July 24 came second in the Aerial Derby Handicap at Hendon, piloted by the owner.
  The Avro 534A Water Baby, a second machine built in October 1919, was a twin float seaplane similar to the rebuilt prototype. It had an unbalanced rudder hinged to a large fin, and a slight reduction in lower mainplane span which imparted a slant to the interplane struts. Flown from Southampton Water, the Water Baby performed very creditably despite water soakage.
  Designated Avro 534B by virtue of its plywood covered fuselage and slightly shortened bottom wing, the third Baby G-EAUG reverted to the perfectly circular rudder. Piloted by Hamersley it just beat Hinkler to win the 1920 Aerial Derby Handicap but was destroyed soon afterwards with serious injuries to Avro pilot D. G. Westgarth-Heslam. The control column universal joint failed during a forced landing with choked carburettor while he was en route to Martlesham to fly the Avro 547 in the Air Ministry Commercial Aeroplane Competition.
  The next machine, produced in July 1920, was the Avro 543 Baby G-EAUM two seater which housed pilot and passenger in an enlarged single cockpit. It was otherwise a standard Baby with the front fuselage lengthened by 2 ft. 6 in. and on test carried Hinkler and Chadwick to 11,000 ft. Flown by Capt. T. Tulley, it averaged 73-67 m.p.h. in the 1921 Aerial Derby but was forced down at Brooklands and fared no better in the 1922 and 1923 King's Cup Races. In 1926 'UM went to Shoreham under the joint ownership of L. E. R. Bellairs and F. G. Miles who removed the ancient Green and attendant plumbing in favour of a 60 h.p. A.D.C. Cirrus I aircooled engine, gravity fed from a large centre section tank. A later owner R. A. Whitehead overturned it in a forced landing at Bury St. Edmunds during the 1928 King's Cup Race, after which it was bought by H. H. Leech for the 1929 race. He sold it to Roper Brown at Southend in 1932. A projected Cirrus I conversion of a single seat Baby as the Avro 534G did not materialise.
  All later Babies were equally remarkable. Avro 534C G-EAXL had the span of both wings further reduced for the Aerial Derby of July 16, 1921 but Hinkler forced landed at Sidcup, Kent. During an air test at Hamble on September 6, 1922 (eve of the first King's Cup Race) the engine cut at low altitude and Hinkler got a ducking when 'XL fell into Southampton Water. The special Avro 534D Baby G-EAYM which first flew at Hamble on September 14, 1921 had all-steel engine bearers, oversize radiator, extra cowling louvres, slightly taller undercarriage, and a luggage locker behind the pilot's seat. It was built to the order of Col. E. Villiers, an ex R.A.F. pilot who flew it at Dum Dum, Calcutta, as a means of inspecting his business interests. This Baby was still flying in 1928.
  Projected variants with folding wings (Avro 534E) and 100 h.p. Bristol Lucifer (Avro 534F) were not built, but in accordance with the Soviet practice of buying single examples of outstanding aircraft, standard Avro 534 single seater G-EBDA was collected from Hamble by Russian pilot Gwaiter in May 1922. His delivery flight from London to Moscow was the first ever made between these capitals. Last of the breed to fly was the Avro 554 Antarctic Baby, a photographic survey development of the projected Le Rhone engined Avro 544 Baby two seater. Identified by rounded wing tips it was built in 1921 for the Shackleton-Rowett South Polar Expedition. Limited shipboard stowage space called for swift dismantling and erection by gloved hands without rigging problems. Tubular steel struts therefore replaced flying wires, N-type interplane struts were used, and all bolts were extra large. An 80 h.p. Le Rhone rotary completely altered the shape of the nose and the tailplane was raised above the fuselage and adjustable for incidence on the ground. After trials on Southampton Water by Maj. C. R. Carr, Shackleton's pilot, the Avro 554 was embarked in the Quest at Tower Bridge and left for the far south. Engine trouble in the Quest compelled Shackleton to proceed direct to Rio de Janeiro, so that he was unable to collect parts of the aircraft left at Cape Town by an earlier vessel, or to use the 554 on the expedition. The missing components were collected on the return journey and the complete aeroplane arrived back in the Quest on September 16, 1922.
  In 1923 the Antarctic Baby was purchased by Capt. R. S. Grandy on behalf of Bowring Bros. Ltd. of St. John's and registered G-EBFE for test flying on wheels at Hamble. Fitted with skis, it was shipped to Newfoundland for seal spotting and occupied a platform on the stern of Bowring's sealer Neptune. A hostile crew refused to allow it to fly but in 1924 Grandy took off from an icefloe alongside the Eagle and spotted a herd of 125,000 seals. The Baby was flown for three more seasons by C. S. 'Jack' Caldwell and retired in favour of an Avro Avian in 1927.
  After the 1920 Aerial Derby Hinkler decided to ship the Baby G-EACQ to Australia and had the engine bay modified so that he could do single handed overhauls in the outback and even remove cylinders with the engine in situ. The machine was first exhibited at the Royal Sydney Easter Show and on April 11, 1921 Hinkler made the now historic 800 mile nonstop flight from Sydney to his native Bundaberg where he landed in the main street and taxied up to his garden gate. The Baby had now been registered G-AUCQ and during the return flight on April 27, overturned on a remote beach in tropical rain. When righted, it was towed 16 miles to Newcastle by horse team and entrained for repair at Sydney where it was sold to H. E. Broadsmith who designed and built a set of floats to the order of a film company. Resulting from several flights from the waters of Botany Bay in 1922, he advised the company that the Baby would be unsuitable for operation in New Guinea and 'C<2 later reverted to a wheeled undercarriage with the front legs farther aft as on Villiers' Avro 534D. After a period as an attraction at a Queensland garage, it passed to W. E. Hart and later to F. Fitzalan of Melbourne, to whom it was re-registered VH-UCQ in 1928. As late as December 1936 a flight of 200 miles from Melbourne to Hamilton, Victoria, was made by final owner J. J. Smith.
  One Baby was used by H. G. Leigh for experiments with narrow chord multiple aerofoils at Hamble in December 1920, but a number of unused airframes remained in store until F. G. Miles bought them early in 1929. His prototype Southern Martlet G-AAII, first flown at Shoreham in August that year, was not (as is often supposed) a conversion of one of these. It resembled the Baby externally and used most of its metal fittings, but the timber work was completely new and the engine mounting, undercarriage and tail unit were of entirely new design.

  Manufacturer: A. V. Roe and Co. Ltd., Hamble Aerodrome, near Southampton, Hants.
  Power Plants:
   (Avro 534 and 543) One 35 h.p. Green
   (Avro 543) One 60 h.p. A.D.C. Cirrus I
   (Avro 554) One 80 h.p. Le Rhone

Dimensions, Weights and Performances:

   Avro 534 Avro 534C Avro 534D Avro 543 Avro 554
Span (upper) 25 ft. 0 in. 20 ft. 0 in. 25 ft. 0 in. 25 ft. 0 in. 26 ft. 3 in.
Span (lower) 25 ft. 0 in. 18 ft. 0 in. 23 ft. 0 in. 23 ft. 0 in. 24 ft. 0 in.
Length 17 ft. 6 in. 17 ft. 6 in. 17 ft. 6 in. 20 ft. 0 in. 22 ft. 5 in.
Height 7 ft. 7 in. 7 ft. 7 in. 7 ft. 7 in. 7 ft. 7 in. 10 ft. 3 in.
Wing area 180 sq. ft. - 176.5 sq. ft. 176.5 sq. ft. 184.5 sq. ft
Tare weight 616 lb.* - 656 lb. 630 lb. 980 lb.
All-up weight 870 lb.* - 950 lb. 970 lb. 1,569 lb.
Maximum speed 80 m.p.h. - - 82 m.p.h.** 90 m.p.h.
Cruising speed 70 m.p.h. - - 65 m.p.h. 70 m.p.h.
Initial climb 500 ft./min. - - 500 ft./min. 330 ft./min.
Range 200 miles - 370 miles 225 miles 190 miles

*With postwar Green engine 610 lb. and 825 lb.
The Leigh multiple aerofoil Baby 675 lb. and 921 lb.
**98 m.p.h. with A.D.C. Cirrus I engine.


Constructor's No. Registered Details
and Registration
   Prototype: crashed at Hamble 30.4.19
534/1 K-131 29.5.19 Avro 534: later G-EACQ; first flown 16.5.19; 4.20 H. J. Hinkler; to Australia 4.21 as G-AUCQ; re-rcgistered 1928 as VH-UCQ: s.o.r.* 1936
534/2 G-EAPS 21.11.19 Avro 534A: crashed 7.9.21
534B/1 G-EA UG 9.7.20 Avro 534B: crashed near Ipswich about 3.8.20
543/1 G-EAUM 12.7.20 Avro 543: C. of A. issued 3.8.23; c/n amended to 5062 at engine change 1926; 11.27 L. E. R. Bcllairs and F. G. Miles; 7.28 R. A. Whitehead; 9.28 H. H. Leech; 9.29 H. R. A. Edwards; 8.32 Roper Brown; s.o.r. 12.34
534C/1 G-EAXL 27.6.21 Avro 534C: crashed in Southampton Water 6.9.22
5049 G-EAYM 17.9.21 Avro 534D: first flown 14.9.21; withdrawn from use at Calcutta in 1929
5064 G-EBDA 28.4.22 Avro 534: sold in Russia 13.6.22
5040 nil - Avro 554: built 1921; registered to Avro 1.2.23 as G-EBFE; to Newfoundland 1923; scrapped 1927
The two seat Avro 543 Baby G-EAUM at Hamble, July 1920, in its initial form with 35 h.p. Green engine.
G-EAUM at Shoreham 1926 with 60 h.p. A.D.C. Cirrus I aircooled engine.
The clipped wing Avro 534C racer at Hamble, June 1921.
The tropicalised Avro 534D Baby built for India.
Hinkler's famous Turin flight Baby G-EACQ at Hamilton, V., Australia, as VH-UCQ in 1936.
H. J. Hinkler and H. G. Leigh at Hamble in December 1920 with the experimental 'Venetian blind' wing Baby.
Maj. C. R. Carr taxying the Avro 554 Antarctic Baby on Southampton Water in 1921.
Avro 548

By 1918 successful development of the in-line engine was already ending the long career of the rotary. The in-line was not only less complex and more easily maintained, but less extravagant in fuel and oil. It was not therefore surprising that A. V. Roe’s ingenious civil adaptations of the 504K embraced an economical engine of this type, particularly as tens of surplus thousands were to be had at give-away prices.
Experiments began at Hamble in October 1919 with the Avro 545 G-EAPR, an experimental 504K with 90 h.p. Curtiss OX-5. This American eight cylinder Vee watercooled engine needed spiral tube radiators on each side of the front cockpit in the manner of the Avro Type E prototype of an earlier era. Such an installation, with its heavy and potentially troublesome plumbing, would not have appealed to private owners and final choice fell on the aircooled 80 h.p. Renault, a similar engine which drove a four bladed wooden airscrew.
Designated Avro 548, first flown at Hamble by H. A. Hamersley late in 1919, flown to Farnborough for checks on January 13, 1920 and certificated in the following March, the first Renault Avro G-EAPQ was a 504K with the dual control removed to carry two passengers in tandem behind the pilot. Fuel, entirely gravity fed, was carried in a large centre section tank and a false decking covered the large rear cockpit so that each occupant had his own windscreen. This machine was the only Avro 548 to have external elevator control wires running from cranks above the lower wing root. Silver overall with polished cowlings, it graced the Avro stand at the Olympia Aero Show, London, in July 1920 without markings as the ‘Avro Tourist’. The third Avro 548, G-EALF, was available for demonstration flights at Hendon during the Show and on July 28 F Lt. Leslie flew Prince Alfonso d’Orleans to Farnborough in it.
The trade slump killed any potential market, and a projected trainer version (Avro 553) was shelved, but the prototype was repainted in wartime drab for Capt. E. D. C. Herne who used it for a photographic survey of the whole of England, the entire coastline of Belgium and France as well as all the major Belgian inland towns. When King George V visited Belfast, ’PQ was flown 700 miles from Croydon to Belfast and back in one day, yet total repairs after 30,000 miles in 18 months amounted to only ?2 for a set of control cables, and 3d. for a valve spring. W. G. Pudney afterwards acquired it and ran a joyriding business at Croydon throughout 1922.
Three other Avros 548s built at Hamble were without the false decking and had a large, double rear cockpit. One was sold in Uruguay and another, G-EAFH (formerly K-147, 504K test bed for the 170 h.p. A.B.C. Wasp I), spent 1921 at Swansea with the Welsh Aviation Company and won all three races at the Croydon Meeting of September 17, 1921 piloted by F. G. M. Sparks. When the firm went into liquidation, pioneer private owner Dr. E. D. Whitehead Reid of Bekesbourne, Canterbury, bought it for a mere ?12 10s., converted it to two seater and flew it in and out of fields on his professional rounds until 1927. G-EAFH then returned to joyriding, first at Squires Gate and in 1931 at Southport sands with the Giro Aviation Co. Ltd., finally crashing there on May 31, 1935 during a low altitude aerobatic display. A. V. Roe and Co. Ltd. built only three other 548s, dual trainers G-EBIT - ‘IV for the North Sea Aerial and General Transport Co. Ltd. Reserve School at Brough in 1924.
The majority of Avro 548s were conversions made by outside firms such as the Aircraft Disposal Co. Ltd. which produced ten at Croydon. Only the first of these, G-EAYD, resembled Avro’s prototype with three separate cockpits. The remainder included five for Reserve Training at Stag Lane by the dc Havilland School of Flying Ltd., one of which was the former Avro Transport Company 504K G-EAAL. Named “Vida”, the latter eventually passed into private ownership at Stag Lane. G-EBPJ, privately owned in 1926 by Nigel Norman, served the Norfolk and Norwich Aero Club at Mousehold 1927-28; and ’PO went to Newcastle Aero Club at Cramlington in the same year.
Surrey Flying Services Ltd. built three; G-EBAJ for airborne radio telephony experiments by Marconi’s Wireless Telegraph Co. Ltd. at Croydon; G-EBBP for private owner Sir Derwent Hall Caine (which later in 1922 reverted to the company for instructional use); and dual trainer G-AABW in 1928. The only difference between these and the genuine Avro-built 548 was the bulged under-cowling. When Marconi ceased experiments in 1926, G-EBAJ joined the rapidly expanding fleet of the Henderson School of Flying Ltd. at Brooklands. A. B. H. Youell flew it at the next year’s Bournemouth Easter Meeting, winning the Business Houses Handicap on April 16, 1927 at an average speed of 74 m.p.h. On October 1 that year it took a prominent part in welcoming home the victorious Schneider Trophy team by flying round Croydon with suitably inscribed yellow banners attached to a crude metal framework. The Henderson School and its successor, the Brooklands School of Flying Ltd., owned nine 548s, six of which they built from spares. Although primarily intended for instructional work, the 548s always went joyriding at coast resorts such as Skegness and Canvey Island in the summer. Two, G-EBRD and ’SC, shipped to South Africa for a pleasure flying season in 1927-28, took part in Cape Town’s first air display on December 11, 1927.
The most important Henderson 548 was G-EAJB, one of Avro’s original 1919 civil 504Ks which had been used at Filton for some years by the Bristol Aeroplane Co. Ltd. as a Lucifer engine test bed. Standard 504K shock absorbers now replaced the special oleo units used at Bristol but 'JB retained the 504N-type ailerons with curved trailing edge. The only other Avro 548 so fitted was Henderson’s second machine G-EBRD, built for South Africa.
In 1925 Maj. F. B. Halford of the Aircraft Disposal Co. Ltd. modernised the 80 h.p. Renault by fitting redesigned cylinder heads and valve gear which raised the power output to 120 h.p. This engine, the Airdisco, was fitted into one of the company’s surplus 504K airframes to create the first Avro 548A. Registered G-EBKN, it had greatly improved all-round performance and became the lively mount of Shoreham private owner A. G. Head. Not to be outdone in publicity by A. V. Roe and Co. Ltd., donors of an Avro 504R to the Lancashire Aero Club in July 1926, the Aircraft Disposal Co. Ltd. simultaneously presented the club with one of their 548 conversions G-EBOK. Soon afterwards, on October 2, T. Neville Stack flew ’OK to victory in the Yorkshire Open Handicap Race at Sherburn, beating the Brough 548As G-EBIT and ’IU. Together with 7F, these had been re-engined with Airdicos but were sold to joyride concerns in 1928 along with ’OK. G-EBIV went to Surrey Flying Services Ltd., Croydon, while 5IT and 7?7 joined ’OK at Squires Gate and there became even better known than the 504K.
The last two British 548s, G-ABMB and ’SV, were built at Barton by Berkshire Aviation Tours Ltd. in 1931 for the Giro Aviation Co. Ltd., their sole cross country flying being the delivery flight to Southport where they worked the beaches for several years. Both were replaced by D. H. Fox Moths in 1934-35 but remained fully rigged in the hangar at Hesketh Park until 1938.
A few Avro 548 conversions were also made overseas. The Canadian Aircraft Co. Ltd. of Winnipeg, importers of six 80 h.p. Renaults in April 1920, built three machines and retained two for charter flying. The third was converted for the McCall Hanrahan Aero Service of Calgary but crashed in less than a fortnight. In 1928 they also built the Hawk-Clark Y-Avro Mallard G-CASY for W. P. A. Straith, using an old 504K fuselage (believed G- CAAQ) with a 75 h.p. Rolls-Royce Hawk engine and Clark Y section wings. In Australia Matthews Aviation Ltd. replaced the Dyak in G-AUBG by an Airdisco; and G-AUBK, flown by E. W. Percival in the Australian Aerial Derby with an 80 h.p. Renault on May 6, 1922, also later received an Airdisco. The only other example, G-AUEW, started life as a Clerget 504K, but was modified progressively to 548 and 548A by E. W. Beckman and Courier Aircraft Ltd. of Brisbane 1926-27.

Specification and data

  A. V. Roe and Co. Ltd., Newton Heath, Manchester; and Hamble Aerodrome, near Southampton, Hants.
  The Aircraft Disposal Co. Ltd., Croydon Aerodrome, Surrey
  Berkshire Aviation Tours Ltd., Barton Aerodrome, Manchester
  The Canadian Aircraft Co. Ltd., Winnipeg, Manitoba, Canada
  The Henderson School of Flying Ltd., Brooklands Aerodrome, Surrey
  Surrey Flying Services Ltd., Croydon Aerodrome, Surrey
Power Plants:
  (Avro 545) One 90 h.p. Curtiss OX-5
  (Avro 548) One 80 h.p. Renault
  (Avro 548A) One 120 h.p. Airdisco
  Span 36 ft. 0 in.
  Length 29 ft. 5 in.
  Height 10 ft. 5 in.
  Wing area 330 sq. ft.
Weights and Performances:
Avro 545 Avro 548 Avro 548A
Tare weight 1,241 lb. 1,338 lb. 1,460 lb.
All-up weight 1,829 lb. 1,943 lb. 2,150 lb.
Maximum speed - 80 m.p.h. 91 m.p.h.
Cruising speed 70 m.p.h. 65 m.p.h. 84 m.p.h.
Initial climb - 350 ft./min. 400 ft./min.
Ceiling - - 11,200 ft.
Range 210 miles 175 miles 300 miles
The Olympia Aero Show model Avro 548 showing the wing root elevator control cranks.
Rear view of the prototype Avro 548 during its 1922 Croydon joyriding season. Note the three individual cockpits.
The Henderson School of Flying joyriding Avro 548 G-EBAJ with framework for towing a ‘Welcome Home’ banner at Croydon when the victorious 1927 Schneider Trophy team returned from Venice.
G-F.RKN, first of the 120 h.p. Airdisco engined Avro 548A machines produced by the Aircraft Disposal Co. Ltd.
G-EBRD, an Avro 548 with tapered ailerons erected by Henderson at Brooklands for the 1927-28 South African tour.
Avro Curtiss-type

  In the summer of 1910 A. V. Roe and Company declared its willingness to build aeroplanes to other people's designs and the first such aircraft was a Farman-type biplane for a Bolton business man. Bolts, fittings and bracing wires were also supplied to Miss Lilian Bland who built and flew the Mayfly biplane of her own design at Carnamony, Belfast. Each of these aircraft was fitted with one of the few examples of the 20 h.p. two cylinder, horizontally opposed, aircooled Avro engines. The Farman-type evidently did not meet with much success as 18 months later, at the end of 1912, the engine and airframe were advertised for sale in new condition for ?45 and ?60 respectively.
  A Curtiss-type, of the familiar outrigger-tail and front-elevator variety with 50 h.p. Gnome rotary, was built in 1911 to the order of Capt. E. W. Wakefield of Kendal. Neither this nor the Farman-type mentioned above was given an Avro designation. Mainplanes were of unequal span and lateral control was by four ailerons on the upper mainplane, the inner and larger pair having semi-circular trailing edges. It was built at Manchester and delivered at Brooklands for test flying on May 19, 1911. After a period with the Avro School during which it was flown by F. P. Raynham, R. C. Kemp, F. Conway-Jenkins and Louis Noel, the Avro-Curtiss was transferred to Lake Windermere where Capt. Wakefield replaced the wheels by a single 12 foot, three step, canvas covered mahogany float built by Messrs. Borwick and Sons of Bowness-on-Windermere. Small cylindrical floats were mounted below the wingtips and the aircraft made its first flight in marine form from Windermere as the "Lakes Water Bird" on November 25, 1911. The pilot was H. Stanley-Adams, a former pupil of the Avro School. Water Bird was the first consistently successful seaplane in the United Kingdom and during the next few months its fame spread quickly and a considerable waterborne joyriding business was done. Sixty flights were made in the first 38 days, the best being of 20 minutes duration up to a height of 800 ft. On December 7, 1911 Stanley-Adams flew the whole length of the lake at a speed of approximately 40 m.p.h. These operations continued throughout the winter, but the night of March 29-30, 1912 brought gales which demolished the lakeside hangar at Cockshott and damaged "Water Bird" beyond repair. Its float, tailplane and rudder (the last still proudly displaying the legend "A. V. Roe and Company, Manchester") are still in the possession of the Wakefield family at Windermere.
  Water Bird's successor, identical, but entirely designed and built at Windermere by Capt. Wakefield's Lakes Flying Company later in 1912, was known as "Water Hen". Its only Avro component was the airscrew and at first it could be distinguished from its Avro-built forerunner by the wingtip floats and straight trailing edges to the ailerons. These were mounted parallel to the chord line of the mainplanes instead of at a considerable angle to it. They were later remounted in the angled position but by that time more drastic modifications had been made and all similarity to Water Bird ceased.

  Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey
  Power Plant: One 50 h.p. Gnome
   Span (upper) 41 ft. 0 in. (lower) 32 ft. 0 in.
   Length 36 ft. 5 in. Wing area 365 sq. ft.
  Weights: Tare weight 780 lb. All-up weight 1,130 lb.
  Performance: Maximum speed 45 m.p.h. Ceiling 800 ft.
  Production: One aircraft only, first flown as landplane 5.11; first flown as seaplane 25.11.11, damaged beyond repair at Cockshott, Windermere 30.3.12