Pterodactyl was the name given to a series of experimental tailless aircraft designs developed by G. T. R. Hill in the 1920s and early 1930s. Named after the genus Pterodactylus , a well-known type of pterosaur commonly known as the pterodactyl, all but the first were produced by Westland Aircraft Ltd after Hill joined them.
Captain G.T.R. Hill developed the Pterodactyl series in an attempt to develop a safer aircraft: many pilots lost their lives when their aircraft stalled, went into a spin and flew into the ground, and Hill wanted to develop a design which was resistant to stalling and spinning. The pioneer J. W. Dunne had previously developed stable aircraft in the form of tailless swept wings and Hill took Dunne's ideas as his starting point. [1]
Helped by his wife, he constructed a prototype which was flown as a glider in 1924. The design gained official interest and in 1925 it was fitted with a 35 h.p. Bristol Cherub engine and taken to Farnborough. It was later demonstrated to the Secretary of State for Air, Sir Samuel Hoare.
All subsequent examples were funded under Air Ministry contract and built by Westland Aircraft, who took on Hill for this purpose. The first Westland-built type, the Pterodactyl I, was built to Air Ministry Specification 23/26. It took the form of a braced shoulder-wing monoplane with fully moving wingtips and a single pusher propeller. If both tips were moved in the same way they functioned as elevators, in opposite ways then as ailerons. It was designated the Mk. IA or IB according to which engine was fitted. It and subsequent models flew initially from RAF Andover, the Mk. IA flying in 1928.
The Mks II and III failed to gain Ministry acceptance. [2]
The next model to be built was a three-seat cabin monoplane to Ministry Specification 16/29, in which the all-moving tips were replaced by conventional ailerons. An unusual feature was the use of variable wing sweep to provide longitudinal trim. Designated the Mk. IV, it first flew in 1931.
The final Westland-built variant, the Mk. V, flew the next year, in 1932. Built to Ministry specification F.3/32, it was a two-seat fighter powered by a 600 h.p. Rolls-Royce Goshawk engine and differing noticeably from the previous versions in having a sesquiplane lower wing and tractor propeller. The lower wing was unswept and of short span, and braced to the upper wing. The forward propeller position, together with the tailless wing configuration, gave the rear gun turret an outstanding field of fire. Despite its performance and flyability in other respects rivalling its conventional competitor the Hawker Hart it was not accepted for production.
Associated with the Mk. V was a complementary Mk. VI design for a pusher variant with front-mounted gun turret, and the intention was to fly a mixed squadron with front-firing machines leading and rear-firing machines behind, but the Pterodactyl programme was cancelled before any order for the Mk, VI had been received. [2]
At the time of cancellation, wind tunnel models of a Mk. VII four-engined reconnaissance seaplane had been tested, and a proposal for a Mk. VIII transatlantic airliner was being worked on.
After World War II, Hill helped develop the similar NRC tailless glider in Canada. Returning to England, he developed the aero-isoclinic wing and helped Short Brothers develop the Short SB.1 and SB.4 tailless swept-wing test aircraft.
Hill's Pterodactyl designs were all intended to handle safely without any definite stall point, allowing reliable recovery without loss of altitude even by inexperienced pilots. The characteristic wing was of moderately tapered and swept planform, with reverse taper at the root to improve pilot vision.
The wing was "washed out", having a slight twist which reduced the angle of incidence progressively towards the tips, providing a near-stationary overall centre of pressure and ensuring that the aircraft was stable in pitch. Thus, no horizontal stabiliser was needed and the craft was tailless, allowing the fuselage to be relatively short.
Early examples used a patented system in which the wingtips pivoted to act as slab elevons providing control in pitch and roll, while later types had more conventional elevons in the wing trailing edge.
Yaw stability was generally achieved by vertical fins, and control by vertical rudders, but the exact arrangement varied between types and even during the flight testing of individual machines. The Mk. I differed in having horizontal "electroscope rudders" on the trailing edge, [i] inboard of the movable wingtips, which acted to provide differential drag. The IA had no vertical surfaces but small fixed fins were added to the IB. [3]
The Pterodactyl 1A of 1926 is held by the Science Museum London.
Aircraft of comparable role, configuration, and era
The Westland Whirlwind was a British twin-engined fighter developed by Westland Aircraft. A contemporary of the Supermarine Spitfire and Hawker Hurricane, it was the first single-seat, twin-engined, cannon-armed fighter of the Royal Air Force.
The Vickers Wellington is a British twin-engined, long-range medium bomber. It was designed during the mid-1930s at Brooklands in Weybridge, Surrey. Led by Vickers-Armstrongs' chief designer Rex Pierson, a key feature of the aircraft is its geodetic airframe fuselage structure, which was principally designed by Barnes Wallis. Development had been started in response to Air Ministry Specification B.9/32, issued in the middle of 1932, for a bomber for the Royal Air Force.
The Avro 679 Manchester was a British twin-engine heavy bomber developed and manufactured by the Avro aircraft company in the United Kingdom. While not being built in great numbers, it was the forerunner of the more famed and more successful four-engined Avro Lancaster, which was one of the most capable strategic bombers of the Second World War.
The Boulton Paul Defiant is a British interceptor aircraft that served with the Royal Air Force (RAF) during World War II. The Defiant was designed and built by Boulton Paul Aircraft as a "turret fighter" to meet the RAF requirement for day and night fighters that could concentrate their firepower on enemy bombers which were not expected to have fighter escorts due to the distance from Germany to the United Kingdom. The Defiant had all its armament in a dorsal turret offering the ability to fire in most directions. The same principle was used in the Royal Navy's Blackburn Roc which was also built by Boulton Paul.
The Supermarine Spiteful was a British fighter aircraft designed by Supermarine during the Second World War as a successor to the Spitfire. Powered by a Rolls-Royce Griffon engine, it had a radical new wing design to allow safe operations at higher speeds and incorporating inwards-retracting undercarriage. Other changes included a larger fin to improve the marginal stability of Griffon Spitfires. Development of the wing was formalised by Air Ministry specification F.1/43; as well as a new aircraft, there was an expectation the wing could be used as a replacement for the elliptical wing on Spitfire production.
The Blackburn B-20 was an experimental aircraft, first flying in 1940, that attempted to drastically increase the performance of flying boat designs. Blackburn Aircraft undertook an independent design study based on a patent filed by their chief designer, John Douglas Rennie for a retractable pontoon float that formed the planing hull.
The Blackburn Firebrand was a British single-engine strike fighter for the Fleet Air Arm of the Royal Navy designed during World War II by Blackburn Aircraft. Originally intended to serve as a pure fighter, its unimpressive performance and the priority allocation by the Ministry of Aircraft Production of Napier Sabre engines to the Hawker Typhoon caused it to be redesigned with an alternative engine as a strike fighter to take advantage of its load-carrying capability. Development was slow and the first production aircraft was not delivered until after the end of the war. Only a few hundred were built before it was withdrawn from front-line service in 1953.
The Boulton Paul P.120 was a research aircraft designed and produced by the British aircraft manufacturer Boulton Paul. It was the last aircraft design by the company to be flown.
The Short SB.4 Sherpa was an experimental aircraft designed and produced by the British aircraft manufacturer Short Brothers. Only a single example was ever produced.
The Blackburn B.48 Firecrest, given the SBAC designation YA.1, was a single-engine naval strike fighter built by Blackburn Aircraft for service with the British Fleet Air Arm during the Second World War. It was a development of the troubled Firebrand, designed to Air Ministry Specification S.28/43, for an improved aircraft more suited to carrier operations. Three prototypes were ordered with the company designation of B-48 and the informal name of "Firecrest", but only two of them actually flew. The development of the aircraft was prolonged by significant design changes and slow deliveries of components, but the determination by the Ministry of Supply in 1946 that the airframe did not meet the requirements for a strike fighter doomed the aircraft. Construction of two of the prototypes was continued to gain flight-test data and the third was allocated to strength testing. The two flying aircraft were sold back to Blackburn in 1950 for disposal and the other aircraft survived until 1952.
The Supermarine Type 224 was a British gull-wing monoplane fighter aircraft designed by R.J. Mitchell at Supermarine in response to Air Ministry Specification F.7/30, which sought to introduce a new fighter to succeed the Gloster Gauntlet. The Type 224 was powered by a Rolls-Royce Goshawk engine, which used an experimental evaporative cooling system.
In aeronautics, a tailless aircraft is a fixed-wing aircraft with no other horizontal aerodynamic surface besides its main wing. It may still have a fuselage, vertical tail fin, and/or vertical rudder.
The Westland Wizard was Westland Aircraft's first attempt to produce a monoplane fighter. The project was privately funded and the prototype design was done in the spare time of the company's engineers. This all happened during 1926, with high-speed performance as the primary goal.
The Westland F.7/30 was a British fighter prototype. A single prototype was built in 1934, but the type was not put in production because its performance fell far below the RAF's requirements. The Gloster Gladiator won the F.7/30 competition.
The Granger Archaeopteryx is a British single-engined, tailless parasol monoplane designed and built in the late 1920s by two brothers, R.F.T. and R.J.T. Granger. The sole example built is currently under restoration for flight.
The Miles M.35 Libellula was a tandem wing research aircraft built by Miles Aircraft as a precursor to a proposed naval carrier fighter. It was named after the Libellula, a genus of dragonflies.
The Gotha Go 147 was a German experimental two-seat tailless aircraft designed in 1936 by Gothaer Waggonfabrik and Dr. A. Kupper. Two examples were built and flown. Development was abandoned before the start of World War II.
The NRC tailless glider, also called the NRL tailless glider, was a two-seat tailless research glider designed by the National Research Council of Canada and built by the National Research Laboratories, at the instigation of G.T.R. Hill who had previously designed the British Westland-Hill Pterodactyl series of tailless aircraft.
The Blackburn F.3 was a British single-engined fighter aircraft produced in response to Air Ministry Specification F.7/30.
The Supermarine Type 324 and Type 325 were British two-engined fighter designs proposed as the replacement for the Supermarine Spitfire and Hawker Hurricane. Neither of them nor a revised design - the Type 327 - to carry cannon was accepted for development and production.
