The Hawker Demon was a fighter variant of the Hart light bomber. During air defence exercises the RAF's Siskins and Bulldogs were often unable to intercept the new Hart bombers, which were sometimes instructed to restrict their height and speed in order to give the fighters a chance, which prompted the development of a fighter variant of the Hart.

While the Hawker Fury offered better performance, lower production volumes made it more expensive and therefore it remained available only in small numbers, so when a fighter version of the Hart was suggested, the Air Ministry selected the type as an interim fighter until higher-performance fighters could be bought in larger numbers.The new fighter variant added a second Vickers machine gun, while the coaming of the rear cockpit was angled to give a better field of fire, and a supercharged Kestrel IS engine was fitted. Evaluation of an initial batch of six aircraft, known as Hart Fighters by one flight of 23 Squadron during 1931 was successful, and larger orders followed for the fighter Hart, now known as the Hawker Demon. The Demon's first flight was on 10 February 1933.

304 Hawker Demons were built, including 232 for the RAF. The Demon was powered by versions of the Kestrel engine. It had an armament of a single rear .303 in (7.7 mm) Lewis Gun with two fixed .303 in (7.7 mm) Vickers machine guns in the nose. Difficulties with the slipstream affecting the performance of the rear gunner, resulted in a segmented, hydraulically-operated retractable windshield (built by British Sports Car manufacturers Frazer Nash) being fitted to all later Hawker Demons. These aircraft were sometimes known as 'Turret Demons'.

The type remained in limited service with the RAF after the outbreak of the Second World War, being used for roles including target towing.

Similarly, some of the RAAF aircraft saw limited service in communications and training roles.

A total of 304 Hawker Demon aircraft were built, with this total being made up of 1 Prototype, 6 Hawker Hart Fighters, 233 Hawker Demons for the RAF, and 64 Hawker Demons aircraft for the RAAF.

Of the production machines, H.G. Hawker built 133 Hawker Hart Fighters and Hawker Demons for the RAF and a further 64 Demons for the RAAF. The remaining 106 Hawker Demon aircraft were built by Boulton Paul Aircraft Ltd.

Demon I
Two-seat fighter aircraft for the RAF.







Australian Demon I
Two-seat fighter aircraft for the RAAF, similar to RAF version but fitted with a 600 hp (447 kW) Rolls Royce Kestrel V engine; 54 built (the first 18 delivered as general-purpose fighters in 1935 and an additional 36 for army co-operation duties delivered in 1936).










Australian Demon II
Two-seat training version for the RAAF, standard Demon fitted with dual controls and provision for target towing, 10 built
Turret Demon
Two-seat fighter version, fitted with a Frazer-Nash gun turret in the rear cockpit.




Specification
Powerplant One 485 hp Kestrel IIS (RAF), 585 hp Kestrel V(DR) (RAF turret equipped), or 600 hp Kestrel V(DR) (RAAF)
Span 37 ft 2 in
Maximum Weight 4,464 lb (fighter); 4,668 lb (turret equipped); 4,716 lb (RAAF fighter)
Capacity and armament Pilot and gunner, two forward-firing Vickers machine gun plus one Lewis gun fired from rear cockpit. RAAF aircraft: provision for up to six underwing bomb carriers.
Maximum Speed 182 mph at 13,000 ft (Kestrel IIS); 182 mph at 16,400 ft (Kestrel V(DR))
Endurance / Range 2 hr 30 min