Avro 539

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Avro - 537 - 1919 - Великобритания Avro - 541 - 1919 - Великобритания

Страна: Великобритания

Год: 1919

Единственный экземпляр

A.Jackson Avro Aircraft since 1908 (Putnam)

Avro 539

  Rushed through the Hamble works in time for the 1919 Schneider Trophy Race, the Avro 539 single-seat twin-float seaplane was the smallest biplane that could be designed round the 240 hp Siddeley Puma engine. Its wooden structure was typically Avro but there was little external resemblance to any of the company’s previous aeroplanes. The fuselage was a rectangular-section box-girder with deep curved fairings above and below to conform to the lines of the engine cowlings. These were a close fit with the cylinder heads projecting through them and cooling was by nose radiator.
  Single-bay mainplanes with rounded tips were rigged with dihedral on the lower, shorter plane only. The tailplane was of generous area and an unbalanced rudder was hinged to a considerable dorsal fin. Four streamlined steel tubes carried two 14 ft single-step wooden floats at a track of 7 ft but there were no wingtip or tail floats. Piloted by Capt H. A. Hamersley, the Avro 539 first flew from Hamble slipway on August 29, 1919, but apart from the national G outlined in white on the rudder, no marks were carried despite the allocation of registration G-EALG eight days before. When taking off for eliminating trials at Cowes on September 3, a float was damaged by floating debris and a separate trial was arranged for September 8. This allowed time not only for repairs but for the fitment of a horn-balanced rudder, a change of fin shape and the display of full registration marks under the revised designation Avro 539A. The Schneider contest took place at Bournemouth on September 10, with the Avro 539A acting as reserve British machine to the Sopwith Schneider and the Supermarine Sea Lion I. These were to compete with French and Italian entries but the race was declared void because of fog.
  Deprived of an opportunity of showing its paces, the aircraft returned to Hamble where it was eventually converted into a landplane for the Aerial Derby at Hendon on July 24, 1920. A rigid V undercarriage was located well forward as on early Avro Babies, the fin area was reduced, and a small streamlined headrest fitted. Still known as the Avro 539A, G-EALG was flown in the race by Capt D. G. Westgarth-Heslam who forced landed drenched in fuel at Abridge, Essex.
  The unlucky racer then returned to Hamble for a more extensive reconstruction to permit the installation of a 450 hp Napier Lion driving a 10 ft diameter Avro airscrew. By removing the frontal radiator it was possible to rebuild the nose with a downward slope to improve both streamlining and forward view. The three banks of cylinders projected from smoothly tapering cowlings which terminated in a conical airscrew boss, the engine being cooled by small radiator units on each side of the fuselage ahead of the cockpit. With an engine almost twice the power and weight of the original, it was necessary to shorten the nose and to strengthen the fuselage by planking it with plywood. A more robust undercarriage with rubber-in-compression shock absorbers was also necessary.
  In this form the machine was re-registered G-EAXM under the designation Avro 539B and first flew at Hamble piloted by D. G. Westgarth-Heslam on July 13, three days before the 1921 Aerial Derby Race in which it was entered. At the end of this, its only flight, he made a perfect landing too far up the aerodrome and overshot into a railway cutting leading to the old RAF Assembly Park. The 539B was completely wrecked and the pilot was seriously injured.

SPECIFICATION AND DATA
Manufacturers:
A. V. Roe and Co Ltd, Hamble Aerodrome, near Southampton, Hants.
Powerplants:
(Avro 539) One 240 hp Siddeley Puma
(Avro 539A) One 240 hp Siddeley Puma
(Avro 539B) One 450 hp Napier Lion
Dimensions:
Span (upper) 25 ft 6 in (lower) 24 ft 6 in
Length (Puma) 21 ft 4 in
Height (Puma) 9 ft 9 in (Lion) 8 ft 6 in
Wing area 195 sq ft
Weights:
(Avro 539) Tare weight 1,670 lb
All-up weight 2,119 lb

Production:
One aircraft only - Avro 539 G-EALG, c/n 539/1, first flown 29.8.19; rebuilt 1920 as Avro 539A G-EALG, c/n 539A/1; rebuilt 1921 as Avro 539B G-EAXM, c/n 539B/1, damaged beyond repair at Hamble 13.7.21

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Журнал Flight

Flight, September 4, 1919.

THE JACQUES SCHNEIDER CUP RACE

The Machines

The Avro Seaplane

   As the accompanying illustrations will show, the Avro machine entered for the Schneider race is quite a small machine, its overall span being only 35 ft. 6 ins., and its length overall 21 ft. 4 ins. In general outline the Avro shows little resemblance to the other members of the Avro family; so little in fact that it would be impossible to identify it as an Avro from mere outward appearances. The detail construction, however, follows more or less standard Avro lines.
   If for no other reason, the Avro would be of interest on account of the fact that it is fitted with the lowest powered engine entered in the race. The Siddeley "Puma" is rated at 240 h.p., whereas the next larger engine - the Isotta Fraschini fitted on the Italian Savoia flying-boat - is rated at 250 h.p.
   This low power, however, does not necessarily mean that the machine will not be fast. Avro machines have in the past proved very efficient, and there is no reason to suppose that the present type will prove an exception. Naturally the makers are not anxious to give particulars of performance at the present time, but the small size of the machine, combined with the careful streamlining of all exposed component parts, should give her quite a good turn of speed.
   The fuselage is of rectangular section as regards its main structure, and is surmounted by a curved top which in front encloses all but the top of the cylinders of the "Puma" engine. The six exhaust pipes project horizontally through the top covering of the body. Behind the pilot's cockpit the deck fairing is fairly deep to form a fairing for the pilot's head.
   The upper longerons, it will be noticed, are straight and horizontal, thus forming a good datum line from which to true up the fuselage.
   The radiator is placed in the nose of the fuselage, motor car fashion, and is of generous proportions. The result is that the body does not taper off towards the nose, as is the case in the Avro Baby, for instance, but has its sides parallel from the neighbourhood of the pilot's cockpit. The warm air is allowed to escape from the engine-housing through louvres in the side of the aluminium cowl.
   A chassis structure of streamline steel tubes carries the two floats, which are of considerable length (14 ft.), and have one small step, occurring immediately underneath the rear chassis strut attachment. No tail float is fitted, the main floats being so placed as to make this unnecessary. The floats are placed fairly far apart, their track being 7 ft., and with the short span bottom plane avoid the use of wing-tip floats.
   One of the most interesting features of the Avro seaplane is the shape of the wing tips. From the plan view of the general arrangement drawings it will be seen that the tips are distinctly rounded, a fact which contrasts markedly with the usual square-tipped Avro wings. Otherwise the wings are characterised by a fairly high aspect ratio - nearly 6.
   The top plane, which is in one piece, has no dihedral angle, but the shorter bottom plane is set at a very marked dihedral angle. There is only one pair of inter-plane struts on each side. Owing to the slight difference in span, the inter-plane struts are sloped so as to get the best load distribution. The centre section struts, or rather the struts supporting the centre of the top plane, are sloped outwards in the usual way to reduce the length of "free" spar in the top plane.
   The tail surfaces also differ from the usual Avro tails. The fixed tail plane, which is of symmetrical section, is no longer rectangular, but is shaped as shown in the plan view. The addition of a fin, doubtlessly necessitated by the deep nose of the body and by the side area presented by the two long floats, changes the appearance of the tail, and the rudder has not the usual semi-circular balance which characterizes so many other Avro machines.
   Altogether the Avro seaplane, which, by the way, answers to the series number 539A, impresses one as being a very serviceable little machine, not only for the race contemplated, but also for purposes other than racing.

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Описание:Description:

A.Jackson Avro Aircraft since 1908 (Putnam)
A.Jackson British Civil Aircraft since 1919 vol.1 (Putnam)
Журнал Flight

D.James - Schneider Trophy Aircraft 1913-1931 /Putnam/

The Avro 539 Falcon taking off during the elimination trials for the 1919 contest. The large amount of 'down' aileron on the port mainplanes and the way the port float is digging in make an interesting comparison with the photograph of the Nieuport
Журнал - Flight за 1919 г.

Capt H. A. Hamersley coming ashore at Hamble on 29 August, 1919, in the Avro 539A G-EALG Schneider Trophy entrant.
A.Jackson - Avro Aircraft since 1908 /Putnam/

The Avro 539 racer at its first launching with the original rounded rudder.
Журнал - Flight за 1919 г.

THE AVRO-PUMA SCHNEIDER SEAPLANE: Preparing the machine for a trial flight. In the cockpit is Capt. Hamersley, M.C., who will pilot the machine in the race
A.Jackson - Avro Aircraft since 1908 /Putnam/

HORS DE CONCOURS: The Avro seaplane was not allowed to start in the race, but Capt. Hamersley brought her down and went round the course a few times by way of a demonstration.
Avro 539A G-EALG at Bournemouth on September 10, 1919, showing the horn-balanced rudder and enlarged fin.
Журнал - Flight за 1919 г.

Schneider Cup Entrants in dock. - The Avro Seaplane having her float repaired. Note the large fin and balanced rudder which have been substituted for the original ones.
A.Jackson - British Civil Aircraft since 1919 vol.1 /Putnam/

The Avro 539A G-EALG with which Capt D. G. Westgarth-Heslam was forced to retire during the 1920 Aerial Derby.
A.Jackson - Avro Aircraft since 1908 /Putnam/

G-EALG in landplane form at Hendon on July 24, 1920, for the Aerial Derby Race.
A.Jackson - British Civil Aircraft since 1919 vol.1 /Putnam/

The machine after reconstruction as the Avro 539B with Napier Lion engine, running up at Hamble on July 13, 1921.

Журнал - Flight за 1919 г.

THE AVRO SCHNEIDER CUP SEAPLANE. - Plan, side and front elevations, to scale
A.Jackson - Avro Aircraft since 1908 /Putnam/

Avro 539

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