Work on what would become the Bugle effectively commenced at Boulton & Paul following the Air Ministry’s release of Specification 30/22, which sought a new twin engined heavy bomber to equip the Royal Air Force (RAF).
However, this effort was not a clean-sheet design, as it drew extensively on the company’s existing experiences with aircraft such as the Bolton and Bourges.
The new design shared its basic configuration with the preceding Bourges, which had been developed during the final months of World War I with positive results, but had been terminated, due to the conflict’s end.
The Air Ministry was suitably interested in the proposal that a pair of prototypes, J6984 and J6985, were ordered for evaluation purposes.
In response to an Air Ministry directive which forbids the placement of fuel tanks within the fuselage, fuel was instead accommodated within semi-circular tanks hung beneath the upper wing’s inner bay area.
The engines, which were initially a pair of Bristol Jupiter II air-cooled radial engines, each capable of producing up to 400 hp (298 kW), were housed within streamlined nacelles that had a patented hinged mounting, which was designed so that the engines could be swung out of situ while on the ground for ease of maintenance.
400 hp (298 kW) Bristol Jupiter II radial engines
Napier Lion W-block engines
39 ft 9 in (12.12 m)
62 ft 6 in (19.05 m)
15 ft 8 in (4.78 m)
925 sq ft (85.9 m2)
8,914 lb (4,043 kg)
2 × Napier Lion water-cooled W12 engine,
450 hp (340 kW) each
112 mph (180 km/h, 97 kn) at sea level
0.303 in (7.7 mm) Lewis guns at nose and dorsal positions