(Copyright Arthur Bentley)

The Tempest II had been intended to be powered by the 2,250hp Sabre Mk IVA in-line liquid cooled engine. Sir Sydney Camm however felt that the radial engined Tempest Mk II would offer the ultimate in performance for the Typhoon/Tempest line and, as a result, considerable effort was made to improve the efficiency of the 2,210 hp Centaurus air cooled radial engine.

During the test flight of the engine in a Tornado prototype (HG641) the engine and oil temperatures remained constantly near the maximum allowable and there was a high amount of carbon monoxide gas in the cockpit.

The RAF technicians, studying a captured Fw 190, found that the Germans had solved the problem of cooling a closely cowled radial engine. They used an annular oil cooler which was built into the leading edge of the cowling and cooled by an engine driven fan. The engine exhaust system avoided the use of a collector ring and gases were dis- charged through individual exhaust pipes mounted in front of exit louvres on each side of the fuselage.
Hawker engineers redesigned the Tempest II with a modified Centaurus IV, which incorporated much of the German technology. This resulted in what was probably the cleanest radial engined fighter of Second World War. The proto- type (LA602) made its maiden flight on 28 June 1943.
Test with LA602 reavealed that the aircraft suffered from engine vibrations. These were solved by mounting the engine on six shock absorbing rubber-packed mountings. These mounts prevented the installation of the Centaurus XII engine (which was originally intended to power production Tempest IIs) and the Centaurus V was chosen as the production power plant.