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Hawker P.1127

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P.1127 and Kestrel
Hawker P. 1127 - NASA.jpg
Hawker P.1127
Type Experimental VSTOL aircraft
Manufacturer Hawker
Designed by Sydney Camm
Maiden flight 19 November 1960 (P.1127)
7 March 1964 (Kestrel)
Primary users Royal Air Force
Number built 5 P.1127s
9 Kestrels
Variants Hawker Siddeley Harrier

The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 were the development aircraft that led to the Hawker Siddeley Harrier, the first VTOL jet fighter-bomber.


In 1957, the Bristol Engine Company informed Sydney Camm of Hawker that they had a project to combine their Olympus and Orpheus jet engines to produce a directable fan jet (an idea approached theoretically by the Frenchman M. Wilbaut). Hawker took the planned engine as a basis for a plane that could meet the current NATO specification for a Light Tactical Support Fighter. At the time there was no financial support for the development from the Treasury, but aid was found through the Mutual Weapon Development Project (MWDP) of NATO to keep the project running, in spite of the atmosphere post the 1957 Defence White Paper which was leading to cancellations of many other projects. By 1958, the British Air Staff showed some interest, but no further MWDP funds were available - much of the money was tied up for the Vickers Swallow swing-wing aircraft project. Some model work was done by NASA at Langley Field for the project. In April 1959 a formal request for the manufacture of prototypes was received and Hawker test pilots travelled to the US to gain VTOL experience on the Bell X-14.



File:Hawker P.1127 prototype Brooklands.jpg
The last of the six P.1127 prototypes (XP984), later converted to the first Kestrel prototype with Pegasus 5 engine and swept wing.

The first prototype P.1127 was delivered in July 1960 for static engine testing and joined in October that year by the actual Pegasus flight engine designed by Sir Stanley Hooker. The first tethered flight took place the same month, and free flight hover in November following which publicity photos were made available.

NATO now had a requirement, NBMR-3, specified for a VTOL aircraft, but one expected to have the performance of an aircraft like the F-4 Phantom along with VTOL capability. Hawker drafted the P.1150, a supersonic P.1127 and the P.1154 which would meet NBMR-3. The latter was a winner of the NATO competition and development continued until cancelled at the point of prototype construction in 1965.

Four more prototypes were ordered and the first true (conventional take off) flight of the P.1127 took place in February 1961. Its first complete VTOL to forward flight took place in September 1961. Through this period improved Pegasus engines were being delivered, the Pegasus 3 capable of 15,000 lbf (67 kN) of thrust. In 1963 a vertical landing was demonstrated on HMS Ark Royal, but later that year, the first prototype plane, XP831, crashed, without loss of life, at the Paris Air Show.

Kestrel FGA.1

File:Hawker Siddeley XV-6A Kestrel USAF.jpg
Hawker Siddeley XV-6A Kestrel in USAF livery

Nine evaluation aircraft were ordered as the Hawker Siddeley Kestrel FGA.1, which was an improved version of the P.1127, the first flying on March 7, 1964. The Kestrel had fully swept wings and a larger tail than the P.1127, and the fuselage was modified to take the larger 15,000 lbf (85 kN) Pegasus 6 engine.

Due to interest from the US and Germany the Tri-partite Evaluation Squadron (TES) was formed, staffed by military test pilots from Britain, the US and West Germany. After testing at RAF West Raynham, during which one aircraft was lost, the eight surviving evaluation aircraft were transferred to the USA for evaluation by the Army, Air Force and Navy (including USMC) as the XV-6A Kestrel. After Tri-Service evaluation they were passed to the USAF for further evaluation at Edwards AFB.


At the time of the development of the P.1127, Hawker had started on a design for a supersonic version, the Hawker P.1154. After this was cancelled in 1965, the RAF began looking at a simple upgrade of the Kestrel as the P.1127(RAF).

In mid-1966, the P.1127(RAF) was ordered by the RAF as the Hawker Siddeley Harrier GR.1, with the first preproduction aircraft flying the following year.


Three prototypes have survived to the present day, and one of these, XP984, is on display at the Brooklands Museum, Surrey. Another is in The Science Museum.[1]

TV Appearance

Both a P.1127 and a Kestrel, masquerading as one aircraft, appear in the 1966 Flight Plan episode of the Roger Moore TV series The Saint. The plot involves a P.1127/Kestrel (called the Osprey in the episode) being stolen and flown behind the Iron Curtain by RAF pilot William Gaunt.



Specifications (Kestrel FGA.1)

General characteristics


See also

Related development

Comparable aircraft

Related lists
List of VTOL aircraft See also




  • Cowan, Charles W. (ed.) Flypast 2. Windsor, Berkshire, UK: Profile Publications Ltd., 1972. ISBN 0-85383-191-2.
  • Hannah, Donald. Hawker FlyPast Reference Library. Stamford, Lincolnshire, UK: Key Publishing Ltd., 1982. ISBN 0-946219-01-X.
  • James, Derek N. Hawker, an Aircraft Album No. 5. New York: Arco Publishing Company, 1973. ISBN 0-668-02699-5. (First publised in the UK by Ian Allan in 1972)
  • Mason, Francis K. Hawker Aircraft since 1920. London: Putnam, 1991. ISBN 0-85177-839-9

External links

Template:Hawker Aircraft aircraft Template:Harrier variants Template:US Army VTOL Template:US STOL and VTOL aircraft

vi:Hawker P.1127

This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia article "Hawker P.1127".