Derived from one bank of six cylinders of the Rolls-Royce Eagle, it produced 75 horsepower at 1,370 rpm.

[1] After Rolls-Royce made the prototypes, the Hawk was manufactured under licence by Brazil Straker in Bristol between 1915 and 1918.

Many engines of this type were used to power the SSZ class coastal patrol airships of which 76 were built.

Post war one engine (serial number 332) was fitted into a specially built hull and launched on Windermere in 1922 with the name Canfly.

The boat and engine are now displayed in a working but non-operational state at the Windermere Jetty museum.