[2] In 1945 the Air Ministry asked for proposals for a new 6,000 hp (4.5 MW) class engine with good fuel economy.

In response to the Air Ministry's 1945 requirements Napier dusted off this work, combining two enlarged Culverins into an H-block similar to the Sabre, resulting in a massive 75 litre design.

Markets for an engine of this size seemed limited, however, so instead they reverted to the original Sabre-like horizontally opposed 12 cylinder design, and the result was the Nomad.

The objective of the design was to produce a civilian power plant with far superior fuel efficiency to the emerging jet engine.

Mounted below this were the rotating parts of a turboprop engine, based on the Naiad design, the output of which drove the front propeller of a contra-rotating pair.

To achieve higher boost, the crankshaft drove a centrifugal supercharger, which also provided the scavenging needed for starting the engine from rest.

The prototype was installed in the nose of an Avro Lincoln heavy bomber for testing: it first flew in 1950 and appeared at the Farnborough Air Display on 10 September 1951.

[4] In total the Nomad I ran for just over 1,000 hours, and proved to be rather temperamental, but when running properly it could produce 3,000 hp (2.2 MW) and 320 lbf (1.4 kN) thrust.

[9] By 1954 interest in the Nomad was waning, and after the only project, the Avro Type 719 Shackleton IV, based on it was cancelled, work on the engine was ended in April 1955, after an expenditure of £5.1 million.