Napier Nomad

The Napier Nomad was a British compound diesel aircraft engine designed and built by Napier in 1949. It combined a twelve-cylinder, two-stroke diesel piston engine with a turbine that recovered energy from the exhaust, aiming at far better fuel economy than the jet engines then emerging. Two forms were tested: the complex Nomad I with two propellers driven by independent stages, and the Nomad II, a turbo-compound engine driving a single propeller that reached the lowest specific fuel consumption seen up to that time. The Avro Lincoln flew with a Nomad I in 1950, but interest had moved to turboprops and the project was cancelled in 1955 after 5.1 million pounds had been spent.