Rolls-Royce Pennine

Pennine
Type	X-24 air-cooled sleeve-valve piston aero-engine
Manufacturer	Rolls-Royce Limited
First run	1945
Major applications	Not flown
Number built	1
Developed from	Rolls-Royce Exe

The Rolls-Royce Pennine was a British 46-litre air-cooled sleeve valve engine with 24 cylinders arranged in an X formation. It was an enlarged version of the 22-litre Exe; a prototype engine was built and tested, but never flew.^[1] The project was terminated in 1945, being superseded by the jet engine.^[2]

A 100-litre 5,000 hp X32 (twin-X16) version of the Exe/Pennine, originally known as the Exe 100, was to have become the Rolls-Royce Snowdon.^[3]

Rolls-Royce air-cooled engines, intended for commercial transport aeroplane use, were named after British mountains, e.g. The Pennines and Snowdon.

Specifications (Pennine)

General characteristics

Type: 24-cylinder supercharged air-cooled 90 degree X layout aircraft piston engine
Bore: 5.4 in (137.1 mm)
Stroke: 5.0 in (127 mm)
Displacement: 2791 in³ (45.73 l)
Length: 106 in (2692 mm)
Width: 39 in (991 mm)
Height: 37.5 in (952 mm)
Dry weight: 2,850 lb (1,293 kg)

Components

Valvetrain: Sleeve valve
Supercharger: Gear-driven centrifugal type supercharger, single stage, two speed
Fuel type: Petrol
Cooling system: Pressure air-cooled

Performance

Power output: 2,740 hp (2,043 kW) at 3,500 rpm, +12 psi boost at sea level
Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg)

References

Notes

^ Rubbra 1990, p.148.
^ Gunston 1989, p.142.
^ "Rolls-Royce and the Sleeve Valve" (PDF). New Zealand Rolls-Royce and Bentley Club (7–3): 8–15. 2007. Archived from the original (PDF) on 6 December 2010.

Bibliography

Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
Rubbra, A.A. Rolls-Royce Piston Aero Engines - a designer remembers: Historical Series no 16 :Rolls Royce Heritage Trust, 1990. ISBN 1-872922-00-7

[1] Rubbra 1990, p.148.

[2] Gunston 1989, p.142.

[3] "Rolls-Royce and the Sleeve Valve" (PDF). New Zealand Rolls-Royce and Bentley Club (7–3): 8–15. 2007. Archived from the original (PDF) on 6 December 2010.

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