Hawker Siddeley P.1127 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 Engine Company's choice to invest in the creation of the Pegasus vectored-thrust engine. Testing began in July 1960 and by the end of the year the aircraft had achieved both vertical take-off and horizontal flight. The test program also explored the possibility of use upon aircraft carriers, landing on in 1963. The first three
Claims to the first powered flight that have received significant attention include: In judging these claims, the generally accepted requirements are for sustained powered and controlled flight. In 1890 Ader had made a brief uncontrolled and unsustained "hop" in his Éole, but such a hop is not regarded as true flight. The ability to take off unaided is also sometimes regarded as necessary. The air historian Charles Gibbs-Smith has said that, "The criteria of powered flight must remain to some extent a matter of opinion." Some notable powered hops were made before the problem of powered flight was finally solved. In 1874 Félix du Temple built