The DH.56 Hyena was developed to meet the requirements of Air Ministry Specification 30/24 for an Army Cooperation aircraft to equip Britain's Royal Air Force. It was a development of de Havilland's earlier DH.42B Dingo, and like the Dingo, was a single-engined two-bay biplane carrying a crew of two. It was armed with a forward-firing Vickers machine gun and a Lewis gun operated by the observer. A hook to pick up messages was fitted beneath the fuselage, while the aircraft was also equipped for photography, artillery spotting, supply dropping and bombing.[1]
The first Hyena flew on 17 May 1925, powered by a 385 hp (287 kW) Armstrong Siddeley Jaguar III radial engine. With this engine it was underpowered, and was quickly re-engined with a 422 hp (315 kW) Jaguar IV before it was submitted for official testing (which was against the requirements of Specification 20/25, which had superseded 30/24). The two prototype Hyenas were tested against the other competitors for the RAF's orders, the Armstrong Whitworth Atlas, the Bristol Bloodhound and the Vickers Vespa, including field evaluation with No. 4 Squadron RAF.[2] Handling close to the ground was found to be difficult, with a poor view from the cockpit, and the orders went to the Atlas, with the Hyena being abandoned, being used for testing at the Royal Aircraft Establishment, Farnborough until 1928.