Hawker

Hart

The Hawker Hart was designed against Specification 12/26, which called for a high performance two seat light day bomber of all-metal construction.

 

Arguably, the requirement arose following Fairey’s development of the Private Venture Fairey Fox, flown in January 1925, exploiting the Curtiss D-12 engine and Curtiss-Reed propeller to achieve a day bomber that was some 50 mph faster than contemporary RAF fighters.

 

The Fox was of wooden construction and only 28 were purchased by the RAF. Nevertheless, the design effectively forced the modernisation of Air Ministry thinking and indirectly led to both the monobloc Rolls-Royce Kestrel engine, and the Hawker Hart family of aircraft.

 

 

Specification 12/26 was demanding for its day and resulted, in the Hart, in a single bay biplane with all-metal primary structure married to a cleanly-cowled 12-cylinder Rolls-Royce Kestrel engine. The first prototype J9052 was flown for the first time in June 1928.

 

The pilot sat ahead of a rear gunner / bomb aimer, equipped with a Lewis gun for self-defence, mounted on a gun-ring of Hawker design. The swept upper wings featured a deep cut-out in the centre-section to improve the pilot’s upward view. Splayed-out N-type interplane struts were used and the lower wing was unswept.

 

Selected following competition, production followed against Specification 9/29. In the event, 1,004 Hart aircraft were built, of which Hawker constructed 234.

 

Contract production was undertaken from 1931 by Gloster Aircraft Co Ltd (46), Sir WG Armstrong Whitworth Aircraft Ltd (456), Vickers (Aviation) Ltd (226), together with 42 aircraft under licence at Trollhäten, Sweden.

 

The Hart was an outstanding design, which gave rise to many variants. Developments included the Demon, Audax, Osprey, Nimrod, Hind, Hardy, Hartbees, Hector and Fury. These types are discussed separately.

 

 

The RAF used the Hart in both its original light bomber role and as the Hart Trainer, fitted with dual control and with all armament deleted. The Hart Trainer also featured reduced sweep of the upper wing to compensate for changes in centre of gravity when the military equipment was removed.

 

In addition, the Hart was used in a number of roles, with variants for communications, operation in India and tropical regions.

 

 

The type was also used by Canada (1), Estonia (8), South Africa (320+ ex-RAF), Southern Rhodesia (ex-RAF aircraft), Sweden, Yugoslavia (4 loan aircraft) and Egypt (14 ex-RAF). Swedish aircraft were powered by the 580hp Bristol Pegasus radial engine, four aircraft being built by Hawker, followed by 42 constructed locally.

 

 

The Hart was also extensively used for engine testing, various examples being host to various versions of the Rolls-Royce Kestrel, Napier Dagger, Bristol Perseus, Mercury, Pegasus and Jupiter, and the Rolls-Royce PV12 and Merlin.