The Hawker Hotspur was a Hawker Henley redesigned to take a Boulton-Paul semi-powered four-gun turret.
It was designed in response to Air Ministry Specification F.9/35, which required a powered turret as the main armament to replace the Hawker Demon.
In the same fashion as the Henley, the Hotspur used standard Hawker Hurricane outer wing panels.
One prototype aircraft, K8309, was built in 1937, fitted with armament of four 0.303 in (7.7 mm) Browning machine guns in a Boulton Paul dorsal turret plus one .303 in (7.7 mm) Vickers machine gun mounted in the front fuselage.
The completion of the prototype was delayed until 1938, by which time the rival Boulton Paul Defiant had already flown.
The Hotspur first flew on 14 June 1938 with only a wooden mock-up of the turret and with ballast equivalent to the weight of armament.
As Hawker was committed to the production of Hurricanes and Gloster to Henley production, there was insufficient capacity to introduce another type and production was abandoned.
The mock-up turret was removed, and a cockpit fairing installed.
Planned production by Avro to Specification 17/36 was abandoned and the prototype, less turret, was used at the RAE Farnborough to test flap and dive brake configurations until 1942.
32 ft 10.5 in (10.02 m)
40 ft 6 in (12.34 m)
13 ft 10 in (4.22 m)
342 sq ft (31.8 m2)
5,800 lb (2,630 kg)
Max take-off weight
7,650 lb (3,470 kg)
1 × Rolls-Royce Merlin II hp V-12 inline piston engine,
1,030 hp (768 kW)
316 mph (510 km/h, 275 kn)
28,000 ft (8,500 m)
4 × .303 in (7.7 mm) Browning machine guns in a Boulton-Paul turret.