Rolls Royce Hawk

The Hawk is a British aero engine designed by Rolls-Royce in 1915. Derived from one bank of six cylinders of the Rolls-Royce Eagle engine, it produced 75 horsepower at 1,370 rpm. Power was progressively increased to 91 hp by February 1916, and 105 hp by October 1918.

After Rolls-Royce made the prototypes, the Hawk was manufactured under licence by Brazil Straker in Bristol between 1915 and 1918. During this period 204 engines were built, and the Hawk earned a reputation for high reliability.

It is said that Royce developed the engine having seen coastal blimps struggling over the English Channel with unreliable and underpowered engines. Many engines of this type were used to power the SSZ (Sea Scout Zero) class coastal patrol airships of which 76 were built. They were capable of patrols of 30 hours duration.