Saunders-Roe SR.53 Mixed-Power Interceptor

The Saunders-Roe SR.53 was a British clipped-delta experimental interceptor combining a de Havilland Spectre rocket motor with an Armstrong Siddeley Viper turbojet. Two prototypes were built from an order for three. John Booth flew XD145 for the first time at Boscombe Down on May 16, 1957. Although production plans were cancelled, the prototypes continued experimental work. XD151 was lost in a takeoff accident on June 5, 1958, killing Booth; XD145 resumed testing in 1959 with Peter Lamb and investigated the supersonic flight envelope. Its last flight was on October 20, 1959. The surviving airframe later supported ground rocket-engine trials and entered the RAF Museum collection.