Rolls Royce Griffon
The Rolls-Royce Griffon was a V-12 - aircraft engine from Rolls-Royce . Series production began in 1942 and lasted until 1955. During this time, 8,108 engines were manufactured in plants in Derby, Crewe and Glasgow.
According to the Rolls-Royce tradition of the time, the name of the engine comes from the bird world: the griffon vulture (English: Griffon Vulture).
development
The first Rolls-Royce Griffon was a performance-degraded Rolls-Royce R , which was put to the test for the first time in 1933. Due to the priority to make the Rolls-Royce Merlin operationally safe, the work was stopped without this version ever being installed in an aircraft. When it became clear that there was a need for an aircraft engine with a performance above the Merlin, development was resumed in 1939. The engine was redesigned according to the knowledge gained in the meantime. This version was named Griffon II and was first tested in November 1939. Considerable efforts had to be made to make an engine of this displacement so compact that it could be built into the airframe of the supermarine Spitfire and Hawker Hurricane fighter that has since been built. For example, the camshaft drive moved to the front of the engine. Further installation space could be saved by making a double ignition magnet ready for production.
Insert versions
The first engines in series production were delivered with a single-stage 2-speed charger in 1942 and powered the prototype of the Fairey Firefly and the first three school variants of this type of aircraft. The charger was switched by means of a piston charged with oil pressure. One derivative - the Griffon IIB - was used in the Spitfire, the Bristol Beaufighter II , the Hawker Henley , the Hawker Tempest III and the operational version of the Firefly I. The first Spitfire Mk.IV DP845 , a Mk.III modified by shorter wings and equipped with this engine, also known as Griffon RG.2SM , flew for the first time on November 27, 1941. A total of 767 copies of this version were built in Derby by 1945. The Griffon III version had a modified crankshaft mounting and was only used in the Spitfire XII, as was the otherwise identical Griffon IV, which only differed in a modified propeller reduction. The Griffon VI was upgraded and had a position-independent injection carburetor, it was built into the Seafire XV, XVII and XVIII and the Spitfire XII. The up to a fuel injection identical Griffon was VIII as a drive of the Fairey Barracuda V used. The Griffon XII was also of the same performance, but had a reinforced charger and a different propeller reduction.
The Griffon 29 was manufactured for the Supermarine Seagull ASR 1 , which for the first time had a gearbox to drive counter-rotating propellers.
The 60 series was an altitude motor with a two-stage supercharger fan and two gears, as were the 70, 80 and 90 series. The 100 series then brought a two-stage supercharger fan with three gear ratios and up to 2440 hp. These engines were used in the Supermarine Spiteful , Spitfire 21, Seafire 46 and Seafang XVI .
The Seafire FR.47 and, for a time, the Spitfire 21 and 24 had propellers rotating in opposite directions to minimize the lateral breakaway caused by the strong torques caused by large propellers with correspondingly high moments of inertia.
After the war the Griffon 57 was developed, which with 2500 HP became the most powerful Griffon. It had a water-methanol injection, but only a single-stage charger and was manufactured from 1947 for the Avro Shackleton with a counter-rotating propeller. It was the last Griffon to remain in production until 1955. A version without water-methanol injection, the Griffon 56, was used in the Blackburn B-54 . The last new version, on the other hand, was the Griffon 59, which was presented in 1951 and was used in the Fairey Firefly VII .
Today the Griffon is still used regularly at tractor pulling events.
Constructive execution
The crankcase of the Griffon is made of cast aluminum and is divided into two parts. The cylinder banks, at an angle of 60 ° to each other, are screwed onto the upper half and they carry the seven crankshaft bearings, which are made from a lead bronze alloy. The front area of this housing part is designed as a lower part of the reduction gear, in which the gears for the starter and the camshaft are also located. The lower part of the crankcase forms the engine sump with oil pumps and the water pump. Wet cylinder liners made of steel are inserted into the cylinder banks made of aluminum . The cylinder heads, which are also made of aluminum, sit on the cylinders . Cylinder heads and cylinder banks are anchored to the crankcase with 14 stud bolts, and the heads and cylinders are also separately connected to each other. The valve seats are made of a wear-resistant steel alloy. The valve guides of the inlet valves are made of cast iron, those of the outlet valves are made of phosphor bronze. In each cylinder, two inlet and two outlet valves ensure the gas exchange.
Series
- Griffon II - 1730 hp (1290 kW) in 230 m, and 1490 hp (1110 kW) in 4270 m; built into the Firefly MK.I
- Griffon VI - increased boost pressure, 1850 hp (1380 kW) in 610 m; built into the Seafire Mk.XV and Mk.XVII
- Griffon 57-1960 hp (1460 kW); built into the Avro Shackleton
- Griffon 61 - Introduction of the two-stage, two-speed charger with charge air cooling analogous to the system of the Merlin 61; 2035 hp (1520 kW) in 2135 m and 1820 hp (1360 kW) in 6400 m; built into the Spitfire Mk.21
- Griffon 65 - analogous to Griffon 61 with modified transmission gear; built into the Spitfire Mk.XIV
- Griffon 72 - increased boost pressure to achieve increased performance and flight altitude with 150 octane fuel; 2245 PS (1675 kW) at 2820 m
- Griffon 74 - petrol injection variant of the Griffon 72; built into the Firefly Mk.IV
- Griffon 83 - modified to use counter-rotating propellers; 2340 PS (1745 kW) in 230 m and 2100 PS (1565 kW) in 3740 m
- Griffon 85 - 2375 hp (1770 kW); built into the Spiteful Mk.XIV
- Griffon 89 - 2350 hp (1755 kW); built into the Spiteful Mk.XV
- Griffon 101-2420 hp (1805 kW); built into the Spiteful Mk.XVI
Technical specifications
Griffon 65
- Type: Water-cooled turbocharged 60 ° - V-12 - Aircraft Engine
- Bore: 152.4 mm
- Stroke: 167.6 mm
- Displacement: 36.7 l
- Weight: 900 kg
- Valves: two inlet, two outlet valves per cylinder, sodium cooling of the outlet valves , each driven by a valve push rod
- Charger: two-stage centrifugal charger that can be switched in two gears, automatic boost pressure control via throttle, water-cooled charge cooler between the second stage and the engine
- Mixture formation: Carburettor with automatic mixture adjustment
- Oil lubrication: dry sump with one pressure pump and two suction pumps
- Cooling system: coolant consisting of 70% water and 30% ethylene glycol
- Power:
- 2035 PS (1520 kW) in 2135 m
- 1820 PS (1360 kW) at 6400 m
- Specific power: 41.4 kW / l
- Power-to-weight ratio : 1.69 kW / kg
literature
- Alec SC Lumsden: British Piston Aero Engines and their Aircraft. Airlife, Shrewsbury 1994, ISBN 1-85310-294-6 .
