Hawker Siddeley P.1127 in flight at NASA Langley 1968
Hawker Siddeley P.1127
The Kestrel's first flight was on 7 March 1964. These equipped the Tripartite Evaluation Squadron formed at RAF West Raynham in Norfolk in March 1965.[16] The Evaluation pilots developed a typical sortie routine for the Kestrel of conducting short take-offs (STO) and returning to base on vertical landings.[17] This manner of operation (STOVL) was judged to be the optimal practice.[18] Operating from rough airstrips was also trialled at nearby RAF Bircham Newton, where the aircraft proved adept at traversing boggy ground and taking off from a variety of temporary ground coverings.[19] During testing one aircraft was lost;[15] the evaluations were finalised in November 1965.[20]
Six of the eight surviving evaluation aircraft (the three allocated to the U.S. plus those allocated to Germany) were transferred to the U.S.[15] for evaluation by the Army, Air Force, and Navy as the
XV-6A Kestrel. After Tri-Service evaluation they were passed to the USAF for further evaluation at Edwards Air Force Base, except for two that were assigned to NASA.[21] One of the two remaining British-based Kestrels was attached to the
Blind Landing Experimental Unit (BLEU) at RAE Bedford and the other, XS693, went to Blackburn for modification to take the uprated Pegasus 6 engine.[22]
....Experience gained during naval testing on board the commando carrier HMS Bulwark in 1966 convinced project officers that less reactive materials would be substituted for all uses of magnesium in the Kestrel's airframe, in any further prototypes and production aircraft.[24]