Rolls-Royce Griffon
The Rolls-Royce Griffon was a 36.75 litre, 60-degree V-12 aero-engine, developed from the earlier 'R' racing engine used in the Schneider Trophy races.
The Griffon was designed prior to World War Two and was originally intended as a low-altitude engine for naval aircraft such as the Fairey Firefly but a formal suggestion to fit a Griffon in a Spitfire was made by Joe Smith (who had taken over as Chief Designer at Supermarine's after Mitchell's death) in October 1939, however work by Rolls-Royce on the engine had been halted temporarily to concentrate on the smaller (27 litre) Merlin, which had already surpassed the early outputs achieved with the Griffon.
Only when development of the Griffon resumed was it then decided to fit the engine to a Spitfire, the first example of which was the single Spitfire Mk. IV, DP845 (a modified, clipped-wing Spitfire III) - shown below - flown with a single-stage, two-speed Griffon RG 2SM on 27 Nov 1941.
Pilot conversion from Merlin-engined to Griffon-engined Spitfires was not without teething troubles; the most common problem being the ingrained habit of applying a starboard trim to the aircraft's rudder, to offset the tremendous torque produced at takeoff power. As the Griffon's crankshaft rotated in the opposite direction to that of the Merlin (a legacy of its intended use for naval aircraft), a starboard bias increased the effects of torque. This problem was never fully overcome in land-based Spitfires, although the Seafire FR.47 was fitted with a contra-rotating propeller as standard, thus negating airscrew torque.
Rolls-Royce applied the advances in supercharging used on the Merlin to the Griffon and later Griffon versions featured two-stage supercharging and finally a two-stage, three-speed supercharger.
The two-stage, three-speed Griffon 101 was fitted to the two Supermarine Spiteful XVIs, with one of these aircraft, RB518, achieving 494 mph (795 km/h) with full military equipment, the aircraft being a "production" XIV simply re-engined.
The Griffon was also used in the Avro Shackleton maritime patrol aircraft.
Versions[1]
- Griffon II rated at 1720 hp (1280 kW) and 1495 hp (1110 kW) at 14 500 feet (4400 m)
- Griffon VI rated at 1815 hp (1350 kW)
- Griffon 58 Shackleton
- Griffon 65 rated at 2035 hp (1520 kW) at 7000 feet (2100 m)
- Griffon 66
- Griffon 72 2245 hp (1670 kW) at 9250 feet (2800 m)
- Griffon 74
- Griffon 83
- Griffon 85 2375 hp Spiteful XIV
- Griffon 88
- Griffon 89 2350 hp (1770 kW) Spiteful XV
- Griffon 101 2420 hp (1800 kW) Spiteful XVI
References
- Jeffrey Quill OBE, AFC, FRAeS Spitfire - A Test Pilot’s Story - Arrow Books 1983-89 - ISBN 0-09-937020-4
- 1 Spitfire society