A.Jackson Avro Aircraft since 1908 (Putnam)

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.

SPECIFICATION AND DATA
   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.
   Dimensions:
   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
   Production:
   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.

SPECIFICATION AND DATA
   Manufacturers: A. V. Roe and Company, Brownsfield Mills, Great Ancoats Street, Manchester; and Brooklands Aerodrome, Byfleet, Surrey.
   Power Plant: One 35 h.p. Green
   Dimensions:
   Span 26 ft. 0 in. Length 23 ft. 0 in. Height 9 ft. 0 in.
   Wing area 280 sq. ft.
   Weights:
   Weight of engine without flywheel 150 lb.
   All-up weight 550 lb.
   Performance: Maximum speed 40 m.p.h.
   Production:
   No. 1 "Mercury", Avro experimental, burned out near Wigan 27.7.10
   No. 2 For W. G. Windham, Brooklands

M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)

P.Lewis British Aircraft 1809-1914 (Putnam)

Avro Triplanes 1, 2, 3 and 4

   Lack of success with his 1908 biplane forced Alliott Verdon-Roe to consider a different form of machine to fulfil his ambition to fly successfully. At a time when the pusher lay-out was followed with few exceptions in Britain he pioneered the tractor type and started to construct a triplane. He had the assistance of a partner in the work of building the machine, which had a fuselage of rectangular section, together with triplane wings and a triplane tail. It was to have had a 35 h.p. air-cooled engine with a geared-down propeller, but the partnership was dissolved before the aeroplane could be completed. The fuselage, wings and undercarriage formed the subject of the first aeroplane auction when they were sold by Friswell for ?5 10s.
   At the beginning of 1909 Roe went into partnership with his brother Humphrey. Forced finally to leave his shed at Brooklands, he transferred to a railway-arch workshop at Lea Marshes, Hackney, and began experimenting with his new No.1 Triplane, which was named The Bullseye after the men's trouser braces made by Humphrey's firm Everard and Co., whose money financed the project. The tail unit was of the lifting type, and the machine's longitudinal control was through the variable incidence of the mainplanes; this was operated in conjunction with the wing-warping by a system of levers and rods to the wings, connected at about 5 ft. from the centre line of the aircraft. The wings themselves folded at the same point for ease of transport.
   A triangular section was employed for the wire-braced fuselage, and the mainplanes and tail unit were covered with yellow-cotton oiled paper. Fixed vertical surfaces were at first used between the tailplanes, but they were discarded later and a tailskid was substituted for the original wheel. Bicycle wheels were fitted to the sprung main forks, and the entire triplane was made as light as possible so as to achieve flight on the 9 h.p. of its J.A.P. engine, which replaced the 6 h.p. J.A.P. installed originally in the machine. Roe was assisted during his tests by R. L. Howard Flanders and E. V. B. Fisher, and after short hops during May and on 5th June he finally succeeded in flying for about 100 ft. the following month on 13th July, 1909, making the first powered flight in Great Britain in an all-British aeroplane. The longest distance achieved was 900 ft. ten days later on 23rd July, and short hops were made at the October, 1909, meeting at Blackpool after a 24 h.p. Antoinette engine was fitted to the machine. Later in the year Roe transferred his activities to a better ground at Wembley, making several good flights before crashing while turning on 24th December. The machine survived and has been on show for many years in the National Aeronautical Collection at South Kensington, London, S.W.7.
   After acquiring an eight-cylinder 35 h.p. J.A.P. engine Roe built a new, larger Triplane No. 2 to accommodate it with a span of 32 ft., and showed the aircraft without its engine at the Travel Exhibition at Olympia in July, 909. The machine had managed a flight of some 600 ft. at Wembley when the Brooklands management changed their policy towards aviators and Roe returned there in February, 1910. Three more of the 20 ft. span triplanes were constructed, using J. A.P. engines of 9 h.p., 20 h.p. and 35 h.p. respectively. The 9 h.p. version was sold to the Rangie Cycle Co.
   Yet another Avro triplane, the Mercury two-seater with wood-covered fuselage, was shown at the 1910 Olympia Aero Show. It was tested at Brooklands in March, 1910, and used a 35 h.p. Green engine. The incidence of the 26 ft. span wings was variable from 4° to 11°, the price quoted being ?600.
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SPECIFICATION

AVRO 1
   Description: Single-seat tractor triplane. Wooden structure, paper covered.
   Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
   Power Plant: 6 h.p. J.A.P., 9 h.p. J.A.P., 24 h.p. Antoinette.
   Dimensions: Span, 20 ft. Length, 23 ft. Wing area, 320 sq. ft.
   Weights: Empty, 200 lb. Loaded, 400 lb.

AVRO 2
   Description: Single-seat tractor triplane. Wooden structure, fabric covered.
   Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
   Power Plant: 35 h.p. J.A.P.
   Dimensions: Span, 32 ft. Length, 32 ft. Wing area, 650 sq. ft.
   Weights: Empty, 650 lb. Loaded, 800 lb.

AVRO 2
   Description: Single-seat tractor triplane. Wooden structure, fabric covered.
   Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
   Power Plant: 9 h.p. J.A.P., 20 h.p. J.A.P., 35 h.p. J.A.P.
   Dimensions: Span, 20 ft. Length, 23 ft. Wing area, 320 sq. ft.
   Weights: Empty, 500 lb.

AVRO MERCURY
   Description: Two-seat tractor triplane. Wooden structure, fabric covered.
   Manufacturers: A. V. Roe & Co., Brownsfield Mills, Manchester.
   Power Plant: 35 h.p. Green.
   Dimensions: Span, 26 ft. Length, 24 ft. 6 ins. Wing area, 246 sq. ft.
   Weights: Empty, 450 lb. Loaded, 550 lb.
   Performance: Maximum speed, 40 m.p.h.

Журнал Flight

Flight, June 26, 1909.

MR. ROE'S TRIPLANE.
To the Editor of FLIGHT.

   SIR, - It may come as a surprise to your readers to learn that I have been making dozens of short flights with my British-built aeroplane during the last few weeks; true, they are hardly more than jumps, being only 2 and 3 feet high and 50 or so feet in length.
   Personally, I would have preferred to let this fact leak out on its own accord by winning the L100 and L1,000 prizes for the 100 yds. and 1 mile flight respectively, but, to be candid, to carry 40 lbs. per h.p. has proved a bigger task than I calculated on, for my machine, with self aboard, weighs 400 lbs., and is driven by a 10-h.p. air-cooled J.A.P. motor cycle engine; but I am confident there is sufficient power, and there is every reason to believe I shall continue to get better results with further experiments. Although I have been trying various gear-ratios, pitches, width of blades, diameters, two and four bladed propellers, and have kept a careful record of each experiment, there still remains quite a number of varieties to be tried yet.
   Carrying 40 lbs. per h.p. seems easy enough on paper but rather different in practice.
   The reason the above announcement is made, is because I feel confident that the machine I am now experimenting with has reached a stage well worth while copying and building in numbers, as it is so light and handy, and will obviously keep afloat under perfect control with a little more thrust.
   Perhaps my experiences may be of interest. The first two flights the machine heeled over, and broke the left tips of lowest plane on both occasions. I thought this was due to the torque of propeller, but am glad to say it was my bad steering, and should the machine lurch over, a slight twist of planes brings it back instantly; but running against winds of 12 m.p.h. or less, the machine practically balances itself. It can be steered entirely by twisting main-planes in conjunction with rear vertical rudder when running along the ground, and the front or back of machine can be raised first, according to the angle of main-planes. I usually run along with main-planes at a slight angle; this allows machine to gain speed, and the tail to rise; on increasing the angle of main-planes to about 10° the front comes off the ground, but owing to insufficient thrust it soon comes down again; while it is up it is quite obvious how quickly the machine answers to the steering.
   The aeroplane in question is a triplane (see No. 19, FLIGHT, of May 8th), having 320 sq. ft. of surface, 1 1/4 lb. per sq. ft. loaded, main-planes forward, tail well in rear; the angle of main-planes can be tilted for vertical and twisted for lateral steering. The patented system of bracing the twisted planes will, I believe, prove a valuable improvement, as it is applicable to biplanes, triplanes or multiplanes. The essence of the idea is, one plane is made rigid from tip to tip, and the rest of the planes take their rigidity from this one by means of hinged struts, consequently all planes follow the movement of rigid plane without any lateral or undue strains put upon them. Owing to the rigid plane being stiff from tip to tip, there is no need to have cables and pulleys from their tips. As a result, they are controlled from two points about 5 ft. on either side of the centre line, through levers and rods; the planes are hinged at this point, and can be folded up for transportation without interfering with any part of the steering mechanism.
   My reason for making the machine so light is almost too obvious to be mentioned, and one reason is to produce an aeroplane that will rise at a slow speed, and once off the ground the angle of planes can be reduced, and speed increased; then again, being so light considerably reduces the speed and shocks on landing. One would naturally think a light machine would be more difficult to control in windy weather than a heavy one, but I am of the opinion if the main-planes can be twisted it will be more easily controlled than a heavy one, with rigid planes, and my experiences seem to bear this out.
   Yours faithfully, A. V. ROE.


Flight, July 31, 1909

Flight in England. - Roe's Progress.

   MR. A. V. ROE is making good progress in flight, in spite of the difficulties under which he works. On Friday of last week, July 23rd, he made four successful attempts, of which three were flights of some 300 yards in length each. In the first flight Mr. Roe failed to fully accelerate his engine, and the machine alighted after a brief ascent, but on the second, third and fourth flights, he got going properly and ascended to an altitude of from 6 ft. to 10 ft. above the ground. The last of these flights landed the machine in a corner of the ground which was exposed to a change of wind, and some slight damage was done in descent. Ordinarily, Mr. Roe keeps within an area shielded by a bank of high trees where the mud conditions, if not good, are at least fairly uniform.
   Lea Marshes, where Mr. Roe is experimenting, are not ideal, but the young aviator is making the best of his environment, and considering that he is practically working single-handed, he progresses as fast as can be expected. He is attempting a difficult feat in any case, to fly with an engine of only about 10-h.p., and the fact that he has succeeded thus far is very encouraging.


Flight, August 31, 1909

Roe has a Slight Mishap.

   DURING the last fortnight Mr. A. V. Roe has been out several times on his little aeroplane, and on Monday and Tuesday last he made one or two short flights. Unfortunately a sudden landing on Tuesday morning threw the aviator through the left-hand main middle plane, which will entail a few days' work before flying will be possible again.


Flight, December 11, 1909

Progress by A. V. Roe.

   A CORRESPONDENT writes: "A. V. Roe had his new 20-h.p. triplane out this afternoon at Wembley Park, and made a number of good steady flights the length of the ground, which is about half a mile long. He flew from one end to the other, rising and falling at will, at times maintaining an altitude of from 20 to 30 feet.
   Unfortunately, the circular course has not yet been cleared, so it was not safe to venture round. His control, which is of a novel type, i.e., twisting and tilting the main planes, worked very well, for he had to dodge various obstacles. It is a pity he did not accomplish this, and previous flights, when at Blackpool, since these would have gained for him both the "All-British" and "British Aviator" prizes, amounting to L400."


Flight, January 1, 1910

Mishap to Mr. A. V. Roe.

   AFTER making several good flights at Wembley Park Mr. A. V. Roe had a slight mishap on Christmas Eve, of which we are able to give a snapshot. Mr. Roe endeavoured to turn sharply, but as a result of some recent modifications in the steering arrangements, found it impossible to rectify the tilting movement quickly enough, and this caused the machine to fall, damaging one of the planes. Just previous to this Mr. Roe had made several very successful flights of 400 to 500 yards in length. The damage Mr. Roe hopes to have repaired shortly, when he will make further attempts.


Flight, March 12, 1910

THE SECOND OLYMPIA AERO SHOW.
AEROPLANES.

Roe.

   BRITISH-BUILT triplane, having a span of 20 ft.; the height of the machine is 9 ft. and the overall length 23 ft. The total supporting surface, including that of the triplane tail, is 320 sq. ft. The machine is driven by a two-bladed tractor screw of adjustable pitch, and the steering is effected by a vertical rudder at the rear operated by the feet. The main planes are operated by hand to serve as elevators.


Flight, April 16, 1910

FLYER SILHOUETTES FROM OLYMPIA.

THE AVROPLANE.

Leading Particulars of the Avroplane.

General Dimensions.-Areas-Main planes, 246 sq. ft.; elevator, 74 1/4 sq. ft. ; rudder, 7 sq. ft.
Lengths.-Span, 26 ft.; chord, 3 ft. 6 ins.; camber, 1 1/2 ins.; leverage of rudder, 14 ft.; skid track, 6 ft.; overall length, 24 ft. 6 ins.
Angles.-Incidence, variable from 11 to 4 degrees; dihedral, 1 in 22.
Materials.-Timber, silver spruce struts and spars, ash frame; fabric, Pegamoid.
Engine.-35-h.p. Green.
Propeller.-Roe; diameter, 8 ft.; pitch, 3 ft.; material, birch.
Weight.-Total flying weight, 550 lbs.; loading, 17 lbs. per sq. ft.
Speed of Flight.-40 m.p.h.
System of Control.-Warping of planes, elevator and rudder.
Price.-L6oo.

   THIS was the only triplane exhibited, and represented the outcome of much careful work on the part of its designer, A. V. Roe, who has pioneered this type of machine in England. The special feature of its construction is the provision that is made for altering the angle of incidence during flight, the main planes and also the tail, which is a triplane, and carries part of the load, being pivoted and interconnected with an operating mechanism. In a future design we understand that this feature will be extended by making the camber variable as well as the angle of incidence. A strong but light type of "A" chassis frame is employed, and the machine is supported upon a combination of wheels and skis.


Flight, January 8, 1915.


MILESTONES.

   IN reviewing the long list of modern successful aeroplanes, it is a little surprising to discover how comparatively few can trace their ancestry back, through generation after generation, so to speak, to a prototype which, although perhaps appearing somewhat crude and incomplete in many ways, viewed in the light of present-day knowledge of aeroplane design, had embodied in it nearly all the fundamental ideas that have contributed towards the success attained by its present-day descendants. One reason for the absence of "pedigree" in a good many successful modern machines is, no doubt, that of the pioneers that helped to make history in the earlier days of aviation, comparatively few are still numbered among the leading constructors, and of these again several are now producing machines which, although being classed among the very best of the day, cannot, strictly speaking, be said to be direct descendants of the original type. Among the British designers whose products can justly lay claim to being "Thoroughbreds" must be mentioned in the very front rank the Avros, in which the fundamental idea underlying the design can be traced very clearly back to the old machine on which A. V. Roe did his first flights, which, although they may not have been more than glorified "hops," were nevertheless, even compared to up-to-date achievements, remarkable performances, when it is remembered that they were coaxed out of a machine fitted with an engine of what seems today ridiculously low power. That the modern Avros have proved and are proving so successful is one more proof, if such were needed, that Mr. Roe had already, in those "dark ages," a thorough grasp of his subject, and was sufficiently far-seeing to choose as subject for his experiments a type which was capable of development. The fact that he had to not only overcome aerodynamical difficulties, but also to fight against financial handicaps makes his ultimate success all the more creditable.
   It was in the dark ages when the man who had the temerity to venture the opinion that it was possible for man to fly was regarded by the majority of people as a dreamer and a crank, not to say worse, that A. V. Roe began his experiments. Accounts of his trials and triumphs, as well as of his adversities, are to be found in the first numbers of FLIGHT, and before the foundation of this journal in our sister journal the Auto., and very interesting reading they make. The "Bull's Eye," or Roe 1 triplane, with which Mr. Roe carried out a number of experiments on Lea Marshes in 1908-09 was a very frail affair as will be gathered from the fact that it turned the scale at about 200 lbs. and had a surface of some 300 sq. ft. The body, which was triangular in section, was built up of longerons of deal, the whole being covered with cotton-oiled paper backed with muslin. The engine, a 10 (ten) h.p. Jap, was mounted in the nose of the body, and drove through a reduction gearing a four-bladed propeller. A two-bladed propeller was also tried, and the question of gear ratios, pitch, width of blades and diameter was made the subject of extensive tests, the results of which were carefully noted. The main planes, of which there were three, were swivelled round a horizontal axis, and were at the same time capable of being warped to maintain lateral stability. The triplane tail of the lifting type was rigidly attached to the rear end of the body, and steering up or down was effected by keeping the tail stationary whilst the main planes were swivelled around their axis in order to increase or decrease the angle of incidence. The warping of the main planes and the alteration of the angle of incidence were both effected by a single horizontal lever, whilst the vertical rudder at the rear of the tail planes provided horizontal directional control. The pilot was seated inside the triangular section body some distance behind the main planes, a position which proved very safe in the numerous accidents that were experienced. Several short flights were made on this machine in 1909, the two first of which ended in left hand side-slips, which were at the time thought to be due to the torque of the propeller, but were proved by later experience to be more probably caused by unskilful steering.
   Several machines on similar lines were built, flown, damaged, rebuilt, flown, &c, during 1909-1910, in the course of which experiments the engine power was increased from 10 to 20 and 35 h.p. The next step in the development of the Avros was a new triplane that made its appearance in 1910. In this machine the span of the two upper planes was increased from 20 ft. to 31 ft., whilst that of the lower plane remained as before, 20 ft. The most important change in this machine in addition to the increase in span was the rigid attachment of the main planes to the body, and the substitution of ailerons for warping for lateral control. The triplane tail remained fixed, but steering up and down was effected by a rear elevator instead of by tilting the main planes. The engine fitted to this machine was a 35 h.p. Jap.
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