The Soar was developed in the early 1950s, and was demonstrated at the Farnborough Airshow in 1953 on each wingtip of a Gloster Meteor flying testbed.

It was the smallest aero-engine ever made by Rolls-Royce and was an extremely simple engine with very few parts.

Red Rapier was to be built by Vickers-Armstrong Ltd, Weybridge, Surrey as the Vickers 825.

One-third scale models without engines were built and air launched from a Washington bomber (the Boeing B-29 Superfortress in RAF service) on the Woomera missile range to test the aerodynamics and autopilot operation.

The Soar project was cancelled in March 1965, at a reported total cost of £1.2 million.