The Pegasus was a 9 cylinder one-row radial aircraft engine designed as the follow-on to the Bristol Aeroplane Company's very successful Bristol Jupiter, following lessons learned in the Mercury effort. Sadly Bristol chose to reuse the name many years later for the engine used in the Hawker Harrier, see Bristol Pegasus (jet).

The Pegasus was the same size, displacement and general steel/aluminium construction as the Jupiter, but other improvements allowed the RPM to be increased from 1950 to 2600 for take-off power. This improved performance considerably from the Jupiter's 580hp, to the first Pegasus II's with 635hp, to 690hp in the first production model III's, and eventually to the late-model XXII's 1010hp with improved superchargers (max take-off in all cases).

The most famous use of the Pegasus is on the Fairey Swordfish, and it was also used on the Bristol Bombay. Like the Jupiter before it, the Pegasus was also licensed, but this time only by the PZL company in Poland. They used it on their PZL P.23 Łoś and PZL P.37 designs.

Specifications

For Pegasus X:

Bore / Stroke / Displacement: 5.75" x 7.5", 1753 cu in (28.7 litre)
Compression ratio: (unknown)
HP: 915 hp at 2600 RPM (max continuous), 960 hp at 2475 RPM (take-off)
Weight: 1005 lbs


Bristol Pegasus is also a motor-racing club in Bristol.