The Rolls-Royce Goshawk was a development of the

Rolls-Royce Kestrel The Kestrel or type F is a 21 litre (1,300 in³) 700 horsepower (520 kW) class V-12 aircraft engine from Rolls-Royce, their first cast-block engine and the pattern for most of their future piston-engine designs. Used during the interwar ...

that used evaporative or steam cooling. In line with Rolls-Royce convention of naming piston engines after

birds of prey Birds of prey or predatory birds, also known as raptors, are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals, reptiles and other smaller birds). In addition to speed and strength, these predators ...

, it was named after the

goshawk Goshawk may refer to several species of birds of prey, mainly in the genus ''Accipiter'': * Northern goshawk, ''Accipiter gentilis'', often referred to simply as the goshawk, since it is the only goshawk found in much of its range (in Europe and N ...

. The engine first ran in 1933 and provided 660

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...

(490 kW). Only a few engines were built as the aircraft designs intended to use it were not adopted by the

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...

. The Goshawk was used to power the

Short Knuckleduster The Short R.24/31 (or Short S.18 and nicknamed the ''Knuckleduster'') was a British twin-engined, high-wing cantilever gull winged monoplane flying-boat designed and built by Short to Air Ministry specification R.24/31 for a "General Purpose Ope ...

, the Supermarine Type 224 (a predecessor to the

Supermarine Spitfire The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Grif ...

) and other prototype aircraft.

Design and development

The Goshawk was developed from the Kestrel IV prototype engine, to use evaporative (also known as "steam") cooling. Rather than keep the cooling liquid below its boiling point in the cooling system, the coolant was allowed to boil; the phase change from liquid to vapour takes more heat from the engine, so less weight of coolant is needed. However, the radiator had to be bulkier to accommodate coolant in its gas phase, which increased drag. Twenty engines were built, and flew only in prototypes as a few manufacturers' private ventures and "one-offs". Powers for individual installations are quoted between 650 and . Problems with coolant leaks, coolant pumping and the realisation that large wing-mounted condensing radiators would be vulnerable to combat damage caused the project to be cancelled, although valuable lessons had been learned and were put to good use with development of the later

Merlin Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and le ...

Variants

;Goshawk I :(1932) Developed from the prototype Kestrel IV. ;Goshawk II :(1935) 600 hp. Lowered propeller reduction gear ratio. ;Goshawk III :(1935) 600hp. Further reduction of gear ratio. ;Goshawk VI :660 hp. High ratio reduction gear. ;Goshawk VII :660 hp. Raised reduction gear ratio. ;Goshawk VIII :660 hp. Special experimental engine. Maximum power output: 837 hp.

Applications

The Goshawk was the power unit specified for the twin engined Short Knuckleduster flying boat (''K3574'') to Specification R24/31 and "preferred" for submissions to Air Ministry specification F7/30 for a fighter aircraft. Goshawks were used by all three officially sponsored prototypes, the Supermarine Type 224 (''K2890''),the Westland F.7/30 (''K2891'') and the Blackburn F3 (''K2892''), which only taxied with the Goshawk fitted and did not fly, in addition to two private venture entrants, the

Bristol Type 123 The Bristol Type 123 was a single-seat, single-engine biplane fighter built to a United Kingdom Air Ministry specification for a four-gun fighter in the early 1930s. Only one was built. Development In late 1931 the Air Ministry released Air ...

and the Hawker P.V.3. The Goshawk also powered Hawker's privately developed "High Speed Fury Mk 2" (''K3586'') and "Intermediate Fury" 2" (the latter Hawker's own development aircraft and "hack" serial ''G-ABSE'')"Fighting Breed"
Flight 1951 p692 and the Westland Pterodactyl V (''K2770'') and was installed for trials in the

Gloster TSR.38 The Gloster TSR.38 was a single-engined three-seat biplane designed as a naval torpedo/spotter/reconnaissance aircraft in the early 1930s. It did not reach production and only one was built. Development Gloster built what was at first known ...

(''S1705''), and the first Gloster Gnatsnapper prototype (''N227'').

Application list

* Blackburn F3 *

* Gloster Gnatsnapper *

Hawker Fury The Hawker Fury is a British biplane fighter aircraft used by the Royal Air Force in the 1930s. It was a fast, agile aircraft, and the first interceptor in RAF service capable of speed higher than 200 mph (321 kmh). It was the fighter co ...

* Hawker P.V.3 * Supermarine Type 224 * Westland Pterodactyl V * Westland F.7/30 (sometimes called the Westland P.V.4)

Specifications (Goshawk I)

References

;Notes ;Bibliography * Gunston, Bill. ''World Encyclopedia of Aero Engines''. Cambridge, England. Patrick Stephens Limited, 1989. * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. .
"The Two Rs"
''Flight'' 1954 from archive at Flightglobal.com