A.Jackson Avro Aircraft since 1908 (Putnam)

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 hp 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 hp, and cross-country capability. Final design was dictated by engine availability, the only suitable one in existence being A. V. Roe’s 35 hp 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 powerplant and although at first named the ‘Popular’, soon acquired the type name Baby. The Green Engine Co 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 Co’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 mph 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 on 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 mph 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 eye-witness 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 interplane 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 stages, 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 547A 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 mph 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 hp A.D.C. Cirrus I air-cooled 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-RAF 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 hp 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 Gvajta in June 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 wingtips 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 hp 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 shipped to Sydney where it was repaired and sold to H. 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 ’CQ later reverted to a wheeled undercarriage with the front legs farther aft as on Villers’ Avro 534D. After a period as an attraction at a Queensland garage, it passed to W. E. Hart and later to 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. Though it was withdrawn from use in 1937, J. J. Smith kept the Baby in store until he presented it to the Queensland Museum, Brisbane, where it was placed on display beside Hinkler’s Avro Avian G-EBOV in 1972 painted as G-EACQ.
  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.


SPECIFICATION AND DATA
   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. 6 in. 7 ft. 6 in. 7 ft. 6 in. 7 ft. 6 in. 10 ft. 3 in.
Wing area 180 sq. ft. - 176.5 sq. ft. 176.5 sq. ft. 184.5 sq. ft
Tare weight 625 lb.* - 656 lb. 630 lb. 980 lb.
All-up weight 857 lb. - 950 lb. 970 lb. 1,569 lb.
Maximum speed 78 m.p.h. - - 82 m.p.h.** 90 m.p.h.
Cruising speed 70 m.p.h. - - 70 m.p.h. 70 m.p.h.
Initial climb 500 ft./min. - - 450 ft./min. 330 ft./min.
Range 240 miles - 370 miles 225 miles 190 miles

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


Production:

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

A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)

Avro 534 Baby

   The Baby, first practical light aeroplane produced in Great Britain after the First World War, was a conventional single-seat biplane featuring the traditional Avro circular rudder. Eight of these machines were built in the Avro works at Hamble, each and every one playing its part in laying sure foundations for the light-aeroplane movement which came in later years. The prototype K-131 was fitted with the identical 35-h.p. water-cooled Green engine that had been fitted in A. V. Roe’s famous 1910 Triplane and, despite its age, brought the Baby to victory in the handicap section of the Aerial Derby in June 1919, followed a month later by an outright win in the Victory Trophy Race. To emphasize that it was no low-powered freak, Avro test pilot H. A. Hamersley flew it non-stop from Hounslow Heath to Brussels in 2 hours 50 minutes in August 1919, afterwards going on to demonstrate it at the Amsterdam Exhibition. During a stunt-flying session with the Avro joy-riding campaign at seaside resorts later in the year, the markings were changed to G-EACQ, and on the last day of the following May, H. J. Hinkler flew it non-stop from Croydon, over the Alps, to Turin in g| hours. After exhibition at the 1920 Olympia Aero Show and participation in the Aerial Derby, Hinkler shipped it to Australia, and on 11 April 1931 flew 800 miles non-stop from Sydney to Bundaberg in 9 hours to set up an Australian long-distance record. A few weeks later, after a forced landing on a beach in tropical rain, it was towed 16 miles to Newcastle by a horse-team, and in 1936 was still flying as VH-UCQ.
   The close proximity of Hamble to Southampton Water invited seaplane operations, and it is not therefore surprising that the second machine was a floatplane with extra fin area and orthodox rudder. This was the Avro 534A Water Baby, and, despite teething troubles with water soakage, flew quite successfully until it crashed on 7 September 1921. The third Baby, G-EAUG, built with plywood fuselage, also had tapered ailerons, and was termed the Avro 534B. It was flown by H. A. Hamersley in the 1920 Aerial Derby, the slight reduction in wing area making it a trifle faster than the prototype, and in the event they carried off first and second places. They were followed in July 1920 by the Avro 543 Baby G-EAUM, which carried two passengers in an enlarged single cockpit, but was otherwise a standard Baby with the fuselage lengthened by 2 ft. 6 in. Flown by Capt. T. Tulley, it lapped the 1921 Aerial Derby course at 73-67 m.p.h. until forced down at Brooklands, and the following year was raced with a fairing over the rear seat. In 1926 it lost its superannuated Green and attendant plumbing in favour of the more modern 60-h.p. Cirrus I, and in 1927 went to Shoreham, where it was jointly owned by L. E. R. Bellairs and F. G. Miles, in whom it inspired the idea of building the Martlet. After changing hands several times it ended its days with Roper Brown at Southend in 1934.
   All the remaining Babies were equally remarkable; the Avro 534C G-EAXL had lower wings of reduced span for racing purposes, and after making its initial flight at Hamble in June 1921, was entered in the Aerial Derby of 16 July but Hinkler had trouble with it, and forced-landed at Sidcup. Then in September came G-EAYM, the Avro 534D Baby, which had steel engine bearers, a larger radiator and very ample cooling louvres in the cowlings. This machine was built for service in India to the order of E. Villiers. The next two Babies, however, went to vastly cooler climes, G-EBDA completing in May 1922 the first flight ever made between London and Moscow. The pilot was a Russian named Gwaiter, who had considerable difficulty in crossing Germany, where a Russian subject flying a British aeroplane caused international complications. Last of the breed was the Avro 554 Antarctic Baby built in 1921 as a photo reconnaissance aircraft for the late Sir Ernest Shackleton’s South Polar Expedition. Limited shipboard stowage space called for swift dismantling and erection by gloved hands and without rigging worries. Steel tube struts therefore replaced the flying wires, N-type interplane struts were fitted and all bolts were extra large. Low air temperatures precluded water-cooling and an 80-h.p. Le Rhone rotary was fitted. After trials on Southampton Water by its pilot, Major C. R. Carr, it was embarked in the Quest at Tower Bridge and left for the far south. It was apparently never used, and on its return in 1923 was purchased by the Aerial Survey Co., and as G-EBFE was shipped to Newfoundland. Here it was used for spotting seals during 1924-25, piloted by B. Grundy and C. S. Caldwell.


SPECIFICATION
Manufacturers: 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.
Avro 534 Avro 543 Avro 554
Span 25 ft. 25 ft. 26 ft. 3 in.
Length 17 ft. 6 in. 20 ft. 22 ft. 5 in.
Height 7 ft. 6 in. 7 ft. 6 in. —
Wing area 176 1/2 sq. ft. 176 1/2 sq. ft. 184 1/2 sq. ft.
Tare weight . 607 lb. 630 lb. 1,000 lb.
All-up weight 860 lb. 970 lb. 1,600 lb.
Maximum speed 82 m.p.h. 82 m.p.h. 90 m.p.h.
Cruising speed 70 m.p.h. 70 m.p.h. 70 m.p.h.
Initial climb . 325 ft./min. 450 ft./min. 330 ft./min.
Ceiling 12,000 ft. 12,000 ft. -
Range 240 miles 225 miles -

Журнал Flight

Flight, March 20, 1919.

"MILESTONES"

The Avro Machines

The Avro "Popular," type 534

   This machine is designed for use as a solo machine at flying schools, and is intended to form a step between the two-seater school machines and the higher powered service machines. It should also be quite a useful 'bus for a low-priced sporting model, as its cost and upkeep should not be prohibitive. At the moment of writing the machine has not been actually tested, and so the figures are those calculated for the machine, but they will probably not be far wrong. We regret that there are no photographs available of this machine.


Flight, June 26, 1919.

THE AVRO "BABY" SPORTING BIPLANE
35-40 h.p. Green Engine

   IN the Avro "Milestones" series, published in our issue of March 20, was included a little single-seater machine designed for sporting purposes. In the article mentioned this machine was referred to as the "Popular." The name has since been altered to Avro "Baby." As the former title suggests, the machine has been designed with a view to producing a machine which can be sold at a reasonable price, to be used for sporting purposes, and, one would suggest, which would form a very useful school machine to form a step between the dual control type and the high-speed, high-power model that most pupils will probably be called upon to fly after leaving the flying school. For a solo machine for this class of work the Avro Baby would appear to be particularly well fitted, since it is fairly sensitive on the controls, yet possesses a great amount of natural stability which could not but inspire a beginner in solo flights with confidence. As the Baby, in spite of its relatively small power, has a very good performance it should also become popular with pilots wishing to keep a little runabout for their own personal use, a machine which, while being inexpensive both in first cost and upkeep, is sufficiently in keeping with the modern idea of an aeroplane to provide one with quite good sport.
   As the accompanying photographs and scale drawings will show, the Avro Baby has a very strong resemblance to the other members of the Avro family. This applies not only to the outward appearance of the machine, but also to a great extent to the internal construction. As regards the former, the main distinguishing features of the Avro two-seaters are: planes of high aspect ratio, pronounced stagger, a fuselage fairly long in proportion to the span, and semi-circular rudder with semi-circular balance. All these features are retained in the Baby, although others, such as rectangular planes and tail planes with corners rounded off, have been modified, as will be seen from the plan view.
   While thus retaining the typical features of its predecessors, the Avro Baby has been designed in accordance with modern ideas, as indicated by the single pair of struts on each side, by the outward rake of its centre section struts, and by the low placing of the top plane in relation to the pilot.
   Constructionally the machine follows standard Avro practice. The fuselage, which is of rectangular section, with an arched deck fairing, is of the conventional girder type. The longerons and struts are of spruce, and the bracing is in the form of steel wire. The well-known Avro body sockets and turnbuckles are used, as shown in one of the accompanying sketches. For such a small machine, the pilot's cockpit is surprisingly roomy and comfortable. The seat is of the aluminium bucket type, with an upholstered cushion. A padded head rest is provided, and the deck fairing behind the pilot contains a small locker for carrying small articles such as spares, etc. A three-ply floor covered with aluminium sheet forms the heel rest for the pilot's feet, and the foot-bar is so arranged that the pilot can; by slightly shifting his feet, use either the toes or the instep for steering. The deck fairing in front of the pilot is so arranged that, while giving a good view, it deflects the air from the pilot's face, and it is not necessary to wear goggles when flying this machine. For those who object to feeling any draught at all on their face, a folding wind-screen is provided, but we imagine that most pilots will prefer a slight draught, as this generally helps a pilot to "feel" the speed, etc. For the man who likes to look after his own machine accessibility is of great importance, and this has been well looked after in the Avro Baby by arranging the body covering in such a manner that it may be quickly stripped off so as to afford examination of the body structure.
   The controls are of the standard type, with a foot bar for the rudder control, and a universally mounted steel tube actuating elevator and ailerons. As the control "stick" is mounted at its base, the elevator control cables pass round pulleys mounted on the foot-bar support, and thence to the elevator. The aileron cables pass over universally-jointed pulleys to the crank levers. All the control cables are of standard type, passing through fair leads, and the splices are of the standard Air Board type.
   A large instrument-board is conveniently placed, and carries a very complete set of instruments, including: revolution counter, altimeter, air-speed indicator, radiator thermometer, oil-pressure gauge, cross level, watch and engine switch.
   The power plant is a four-cylinder vertical 35-40 h.p. Green water-cooled engine. The two engine-bearers (of wood) are mounted on transverse supports bolted to the stout struts in the nose of the body. The radiator, which is of the honeycomb type, was built by the Excelsior Radiator Co., of Leeds. It is mounted in the nose of the fuselage, motor car fashion. With regard to the engine fitted in this particular machine, it is of interest to know that this is the identical engine fitted on the Avro biplane on which Capt. Pixton did so much flying in 1912. It is only fair to mention, however, that the engine has been overhauled and improved by Messrs. Green, and has been fitted with aluminium pistons, new type cam shaft, valves and valve cages, and also with an ingenious oil-pressure regulator which regulates the amount of oil used by the engine according to the throttle opening. The petrol tank contains eight gallons of petrol, or sufficient for a flight of over 200 miles, flying at cruising speed. For a sporting machine this range should be ample. The weight and complication of pressure feed has been dispensed with, the fuel flowing to the carburetor by the force of gravity. The oil tank has a capacity of 1 1/2 gallons, and as the engine is of the dry-sump type, the oil is kept in constant circulation through the engine by means of a gear pump.
   From the illustrations it will be seen that the engine is neatly cowled in by aluminium cowling, large inspection doors giving access to every part of the engine, piping and tanks. If necessary, the whole engine cowl can be easily removed. A large exhaust collector on the port side carries the exhaust gases away from the fuselage. With regard to the engine controls, wires have been entirely eliminated, the controls being all of the positive pull-and-push rod type.
   The undercarriage is of the simple Vee type, with struts of circular section steel tube, streamlined with light three-ply fairings, which are in turn covered with linen, doped and painted. The axle is of the divided type, hinged in the centre, and springing is by means of rubber shock absorbers. The tail skid is of simple construction, as shown in the photograph. It is made of ash and has a steel wearing shoe. It is sprung by rubber cord.
   In general arrangement the main planes follow modern practice. The roots of the lower planes are attached to the sides of the fuselage, while the two halves of the top plane are bolted to a centre section carried on four raked struts from the body. As already mentioned, there is only one pair of interplane struts on each side. These struts are of wood, while the four centre section struts are streamline steel tubes. The arrangement of the wing bracing is somewhat unusual. The landing wires do not present any departures from usual practice, being in the plane of the struts. The lift wires, however, are arranged somewhat differently. Although not being in duplicate in the usual sense of the word, the lift wires are four in number on each side. Perhaps their arrangement may be best described by saying that the four lift wires form a letter M, the two top points being secured to the top of the inter-plane struts, while the three lower points are anchored to points on the fuselage. In this manner not only is the lift distributed over a considerable length of the body, but by the angularity of the wires the internal drag bracing is relieved of some of its load.
   Constructionally the planes are built-up in the usual Avro manner. The main wing spars are of built-up box section, while the leading edge is of wood spindled out to a U section. The wing tips and the trailing edges are in the form of steel tubes. The wing ribs are of the wood girder type, with box girder ribs taking the compression load imposed by the internal drag bracing. Ailerons are fitted to both top and bottom planes, the upper and lower flaps being connected by wires.
   From the scale drawings of the machine it will be seen that the tail planes and elevators are of very graceful outline, while the rudder is of the usual Avro shape; this shape of rudder, by the way, has formed one of the distinctive features of the Avro machines for a number of years. No fixed vertical fin has been fitted, as this has been found unnecessary in such a small machine.
   With regard to the performance of the Avro Baby, this can only be described as uncommonly good for a machine of so low power. As the accompanying climb chart will show, the climb curve is practically a straight line, the rate of climb being very good for the power. As regards horizontal speed, this is about 78 m.p.h. near the ground, or in other words quite fast enough for a machine to be used for pleasure flying. The landing-speed in only 32 m.p.h., low enough for a beginner to make a safe landing every time, with reasonable care, and so low as to enable pilots who have been used to the high landing-speeds of modern fighting machines to bring the machine into a very confined space indeed. As the Baby leaves the ground after a very short run, she will be an ideal machine for pilots who wish to go touring, as she can be landed almost anywhere. As regards comfort of flying, we believe that the Avro Baby is to all intents and purposes automatically stable, the Avro test pilot having repeatedly flown her for long periods at a time without touching the controls. This stability, it should be pointed out, has not been obtained at the expense of controllability, for the Baby can be looped, spun, rolled, stalled, side-slipped, etc., with great ease. At full speed the engine revolves at 1,500 r.p.m., but the machine can be flown indefinitely with the engine running at 750 r.p.m., at which speed the petrol consumption is extremely low.
   Altogether, it would appear that the designers of the Avro Baby have succeeded in producing a machine which combines a surprisingly great number of desirable features, and we venture to think that when things settle down a bit more she will become very popular indeed among pilots wishing to enjoy the pleasures of - to substitute a modern saying for the old one "paddling their own canoe" - flying their own 'bus. With regard to price, it has, we understand, been impossible to settle this definitely at present, but it will, we are informed, be as low as possible consistent with good workmanship and finish. Possibly in the neighbourhood of ?500.
   The following figures give the main characteristics of the Avro Baby: Span, 25 ft.; length overall, 18 ft. 6 ins.; height, 7 ft. 6 ins.; weight bare (but including water), 625 lbs.; weight, loaded, 857 lbs.; load per sq. ft., 4.75 lbs.; load per h.p. (at 40 h.p.), 21.4 lbs.; maximum speed near ground, 78 m.p.h.; landing-speed, 32 m.p.h.; climb to 1,000 ft., 1 min. 40 secs.; to 2,000 ft., 4 mins.; to 3,000 ft. 6 mins.


THE AERIAL DERBY

THE MACHINES

No. 14. - The Avro Baby, 35-40 h.p. Green
   Although not generally realised by the majority of the visitors to Hendon, nor by the greater part of the daily Press, the performance of the little Avro Baby, piloted by Capt. Hamersley, was the feature of the Aerial Derby. It demonstrated that, even on a windy day, it is not essential to have at one's disposal an engine of very high power in, order to make a cross-country flight of considerable duration and distance. With the great engines used on War machines in order to get ultra-high performance there is the tendency to form the opinion that such powers are essential to peacetime machines as well. The Avro Baby has demonstrated that this is not so, and that the private owner of a machine, fitted with an engine of very moderate power - and, incidentally, of low cost and upkeep - may count on being able to make cross-country flights on a reasonably great percentage of days throughout the year. As the machine is fully described elsewhere in this issue, no detailed reierence need be made to it here. Suffice it to say that after the race Capt. Hamersley gave a very fine demonstration of "stunting," the little machine being capable of all the tricks indulged in by its bigger brothers. Add to this that she lands at a little over 30 m.p.h., and gets off very quickly, and it will be seen that the Avro Baby forms an ideal machine for the private owner.