Rolls-Royce Pennine
# Rolls-Royce Pennine

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. The project was terminated in 1945, being superseded by the jet engine.

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.

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)
