The Boulton Paul P.120 was a modified version of the delta winged P.111, briefly used to test an all-moving horizontal tail, before being lost in a crash,
The P.111 was a delta wing aircraft with no horizontal tail surfaces, triangular wings and a triangular vertical tail, both of which had detachable pointed tips. It was powered by a Rolls-Royce Nene engine, and made its maiden flight in October 1950.
The P.120 has similar wings and fuselage, but a modified tail. It was produced in response to Air Ministry Specification E.27/49. The aircraft carried an all moving horizontal surface near the top of a short swept back fin, designed to improve stability in flight. Like the P.111 it had powered controls, but unlike the P.111 there was no feedback system on these controls. The front of the fuselage was identical to that of the P.111A.
The P.120 made its maiden flight on 6 August 1950. A problem with the tailplane settings meant that it took an unexpectedly long time to get airborne, but it was reported to be pleasant to fly, and rather less alarming at high speeds than the P.111.
The P.120 was lost on 29 August after a handful of flights, probably because of problems caused by tail flutter in the experimental horizontal surfaces. The lack of a feedback system on the controls meant that the test pilot had no idea that a problem was developing until it was too late. The test pilot, Ben Gunn, spent half an hour trying to nurse the damaged aircraft home, but eventually realised that it wouldn't be possible to land. An attempt to eject nearly went wrong, and the aircraft was upside down when Gunn ejected. Luckily he had accidently pulled his parachute ripcord first, and was saved by his canopy as he dropped into some trees. He thus became the first person to eject from a delta wing aircraft.
The P.120 was the last Boulton Paul aircraft design to be built, although a number of research projects were carried out over the next few years.
Engine: Rolls-Royce RN.2 Nene
Power: 5,100lb static thrust
Span: 33ft 5.5in
Length: 29ft 7.5in
Height: 9ft 6.5in
Empty weight: 10,656lb
Loaded weight: 12,580lb
Maximum take-off weight:
Max speed: Unrecorded
Climb Rate: Unrecorded
Service ceiling: Unrecorded