The Hawker F.20/27 J9123 photographed at Brooklands
The Hawker F.20/27 J9123 photographed at Brooklands in 1928.


The comparatively little-known H.G. Hawker F.20/27 single-seat fighter prototype was powered initially by an uncowled 450 hp Bristol Jupiter VI nine cylinder radial engine.
Designed and built against Air Ministry Specification F.20/27 which called simply for an 'Interception single-seat fighter' which also saw submissions from Armstrong Whitworth (Starling II), Bristol Aeroplane Company (Bullpup) De Havilland Aircraft Company (DH77), Fairey (Firefly II), Saunders (A.10), Vickers  Aircraft (Jockey) and Westland (Interceptor).
The sole example (J9123) flew for the first time in August 1928 and was tested at Aeroplane & Armament Experimental Establishment (A&AEE) at Martlesham Heath towards the end of 1928, demonstrating a maximum speed of 190 mph.
The aircraft returned from Martlesham and was fitted in May 1930 with the prototype of the more powerful 520 hp Bristol Mercury VI engine. When re-tested at Martlesham, it is reported to have suffered from high oil temperatures and was ultimately withdrawn from further testing. It had, however demonstrated a maximum speed of 202 mph at 10,000 ft.
The Hawker F.20/27 J9123 photographed rear
A rear three quarter view of the Hawker F.20/27 J9123 at Brooklands.
Whilst this was an impressive result for an aircraft with an uncowled radial engine, it was already clear that application of the clean, liquid-cooled, Rolls-Royce Kestrel engine (already flying in the Hart and Hornet) would result in further improvements in performance.
The Hawker F.20/27 prototype suffered a minor accident after its return from Martlesham and its Mercury engine was returned to Bristol for further development.
H.G. Hawker turned their attention to the Hawker Fury biplane, in effect a production development of the Hawker Hornet prototype, which had flown in March 1929. The Hawker Hornet was, in effect, an F.20/27 fitted with a closely cowled 480 hp Rolls-Royce F.XIS engine.
The F.20/27 was put to one side and not flown again and in the end the Air Ministry Requirement was withdrawn without any contracts being awarded.
The Hawker Hornet and Fury are described elsewhere on this website.
The Hawker F.20/27 J9123 photographed side view
A side view of the sole Hawker F.20/27 prototype J9123.

Variants & Numbers

Single prototype only (J9123)



Powerplant One 450 hp Bristol Jupiter VI radial engine or 520 hp Mercury VI engine
Span 30 ft 0 in
Empty Weight 2,155 lb
Maximum Weight 3,150 lb
Capacity and armament Single pilot and two fixed forward-firing Vickers 0,303 machine guns
Maximum Speed 190 mph (Jupiter), 202 mph at 10.000 ft (Mercury)
Endurance  Approx. 3 hr 10 min



The prototype F.20/27 does not survive.

Other information

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