Napier Nomad Model E. 145 Horizontally-Opposed Diesel Engine

Type: Reciprocating, horizontally-opposed, diesel, 12 cylinder, liquid cooled

Power rating: 2,271 kW (3,046 hp) at 2,050 rpm

Displacement: 41.1 L (2,505 cu in.)

Bore and Stroke: 152 mm (6 in.) x 187 mm (7.4 in.)

Weight: 1,625 kg (3,580 lb)

D. Napier and Son began building aircraft engines in the World War I era. The Lion series was produced from 1917 until 1932 for military, commercial, and racing aircraft. Napier’s World War II era Sabre engines also powered a number of aircraft. Intended for use in long-range aircraft at the end of World War II, the Nomad was an engineering tour-de-force, although being one of the most complex aircraft engines ever built. Napier designed the Nomad to have the lowest possible fuel consumption by compounding a two-stroke diesel engine with a gas turbine and transmitting the power through a propeller.

The Nomad II, a simplified version of the original design, appeared in 1951 and was intended for the four-engine Avro Shackleton long-range patrol bomber. However, a single Nomad II flew only briefly, in the nose of an Avro Lincoln bomber. Napier cancelled the program in 1955 because the Nomad could not compete with gas turbine engines.