Hawker P.1121 Staff having been unable to understand the concept of the multi-purpose functionality of the aircraft, which would become commonplace on later aircraft. While seeking a new project to take the place of the P.1121, Camm soon began work upon another new and radical aircraft design, designated as the Hawker Siddeley P.1127. The P.1127 would become the Hawker Siddeley Harrier, the first effective vertical take-off and landing (VTOL) combat aircraft. The Hawker P.1121 was envisioned as being one of the first British-built supersonic fighter aircraft, being projected to be capable of speeds of up to Mach 2.5. It was to have
Hawker Siddeley P.1127 Kestrel with a much smaller counterpart on the fin to enable the nose to accommodate a tactical camera instead. An unusual feature of the P.1127 was the installation of a ram air turbine upon the rear fuselage just forward of the fin to provide power for ancillary services in the event of engine failure. Hawker Siddeley P.1127 The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 are the experimental and development aircraft that led to the Hawker Siddeley Harrier, the first "vertical and/or short take-off and landing" (V/STOL) jet fighter-bomber. P.1127 development began in 1957, taking advantage of the Bristol