De Havilland DH.77

de Havilland DH.77

Company type	Experimental fighter aircraft
Industry	Aerospace
Founded	1929
Founder	W.G. Carter, Frank Halford (designers)
Headquarters	United Kingdom
Products	Military aircraft

The de Havilland DH.77 was a British experimental fighter aircraft developed in the late 1920s. Designed as a rapid-climbing interceptor for the Royal Air Force, this lightweight, low-wing monoplane was powered by a modestly rated engine. Despite demonstrating impressive capabilities, only one unit was constructed, as preference was given to the biplane design of the Hawker Fury.

Development and design

In 1927, confronted with advancements in bomber aircraft performance, the British Air Ministry issued Specification F.20/27 calling for a single-seat interceptor. Unlike earlier fighter requirements, this specification targeted short-range interceptors focused on rapid climb rates to high altitudes, equipped with minimal onboard systems. To address this demand, de Havilland independently initiated the development of the DH.77. The design was led by W.G. Carter from the Gloster Aircraft Company, working closely with engine designer Frank Halford. By 1930, de Havilland shifted its focus predominantly to civil aviation, transferring the DH.77 project and the unfinished DH.72 bomber to Gloster.

The DH.77 featured a compact low-wing monoplane layout with a mixed metal and wood structure. It was powered by a 300 hp (224 kW) air-cooled Napier Rapier H-type engine noted for its small frontal area, reducing aerodynamic drag. The wing incorporated distinctive streamlined bracing struts positioned above it, while the undercarriage consisted of a wide-track fixed tailwheel arrangement. Control surfaces included large-span ailerons and a stabilator, enhancing handling and spin recovery capabilities. Armament comprised the standard pair of synchronised Vickers machine guns mounted flanking the cockpit.

File:De Havilland DH77 001.jpg

The sole prototype took to the air on 11 July 1929 with pilot H.S. Broad at the controls. Although its Napier Rapier engine produced only about 60% of the power delivered by the competing Rolls-Royce Kestrel engine used in the Hawker Hornet, the DH.77 achieved notable speeds of up to 204 mph (328 km/h). When carrying a full military loadout, maximum speed decreased to approximately 185 mph (298 km/h). The aircraft was submitted for evaluation at Martlesham Heath by the Aeroplane and Armament Experimental Establishment on 12 December 1929. While the Air Ministry did acquire the prototype, it did not proceed with mass production, instead selecting the heavier and more powerful Hawker Fury, which evolved from the Hornet design. The DH.77 remained operational at Martlesham until 1934.

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