<p>Forerunner of the world's first successful vertical take-off combat aircraft, the Kestrel was developed in Britain by Hawker. The initial six prototypes were built under the company designation P.1127, the first making a historic tethered hovering flight on 21 October 1960. Conventional take-off was first performed in March 1961, and the all-important first transition from vertical to horizontal flight was accomplished on 12 September 1961. US interest in the program was high, and the designation VZ-12 was assigned to the P.1127. Two serials were reserved (62-4507 and 62-4508) but no P.1127s were transferred to USAF control.
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<p>Promising results from the initial P.1127 tests led to an order for nine more advanced aircraft, known in Britain as the Kestrel F(GA).Mk 1. These were funded by a trinational consortium consisting of Britain, Germany and the United States. The first flew on 7 March 1964, and all nine were delivered to RAF West Raynham from December where the Kestrel Evaluation Squadron was formed to fully explore the combat potential of the V/STOL aircraft. In addition to pilots from the Luftwaffe (two) and RAF (four), the KES aircraft were also flown by US Army (two), Air Force (one) and Navy (one) pilots. Ironically, the one US service (Marine Corps) which bought the aircraft after it had matured into the Harrier was missing from the evaluation. Over 600 hours were flown in 938 sorties by the KES, which ended its program on 30 November 1965.
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<p>At this juncture the aircraft were distributed among the three nations. The United Kingdom took two aircraft, the United States four and Germany, which by then was pursuing its own V/STOL program, handed its two aircraft to the US. The remaining aircraft had crashed during KES trials. Using their Department of Defense designation XV-6A, the six Kestrels (64-18261/64-18266) shipped to the US underwent further evaluation with the Navy and Air Force. In the hands of the latter, XV-6As flew 374 sorties in 14 weeks from Edwards, before the service announced it could see no practical application for the type. It was to be another three years before the Harrier caught the attention of the Marines. Meanwhile, in 1966 two USAF XV-6As were handed over to NASA, which subsequently performed some useful work with the type, including the use of thrust-vectoring in combat.
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<hi style=hdr1>Specification</hi>
<hi style=hdr2>Hawker Siddeley—XV-6 Kestrel</hi>
<list style=aflst>
<item><hi format=bold>Type:</hi> single-seat V/STOL research fighter
<item><hi format=bold>Powerplant:</hi> one Bristol Siddeley Pegasus 5 turbofan, rated at 15,500 lb thrust
<item><hi format=bold>Performance:</hi> maximum speed 710 mph at sea level; service ceiling 55,000 ft
<item><hi format=bold>Weights:</hi> empty 9,800 lb; maximum take-off (conventional) 17,000 lb
<item><hi format=bold>Dimensions:</hi> wing span 22 ft 11 in; length 42 ft 6 in; height 10 ft 9 in
