February 8th 1963. Here is XP831 on the deck of HMS Ark Royal after Hawker Test Pilot Bill Bedford had completed the deck landing. This was the first ever vertical landing of a fixed wing aircraft on an aircraft carrier and the last of significant milestones in the proving the prototype’s potential. 3 months later XP831 would crash at the Paris Airshow.
XP831 was the first prototype and had an interesting diary of “firsts”:
XP831 was delivered to Dunsfold in 1960 to commence static engine testing. On 31 August 1960, the Pegasus engine was run for the first time while inside the airframe. Some of the tests were performed from a purpose-built platform at the aerodrome which functioned to deflect the hot exhaust gases away from the aircraft during early hovering trials while more powerful versions of the engine were developed. On 13 October 1960, the first Pegasus flight engine, capable of generating 11,300 lb of thrust, was delivered to Dunsfold.
On 21 October 1960, the initial tethered flight, performed by XP831, was conducted at Dunsfold; at this stage of development, this feat had required the airframe to have been stripped of all extraneous weight and restrictions on the engine meant it could not be run at full power for more than 2.5 minutes at a time. Several tethered flights took place, partially so that the test pilots could familiarise themselves with the hovering controls. On 4th November, the first tethered flight without use of the auto-stabiliser system was accomplished.
On 19 November 1960, the first un-tethered free-flight hover of XP831 was achieved; a week later, the first publicity photos of the P.1127 were released.
On 13 February 1961, XP831 performed its first conventional flight, flown by Bill Bedford and lasting for 22 minutes. Soon after this, XP831 was refitted with a new model of the Pegasus engine, capable of generating 12,000 lb of thrust, prior to embarking on new hovering trials in May 1961. In June, XP831 attained another milestone in the program when it performed the first transition from vertical hover to horizontal flight, initially flying the length of Dunsfold’s runway at a height of 50 meters.
In 1963, following the successful landing on HMS Ark Royal, XP831 publicly crashed at the Paris Airshow. The accident had been caused by a speck of dirt in the air feed lines of the nozzle control motor, which had caused the engine nozzles to stick. XP831 was later fully repaired and resumed development flying. The pilot survived.
XP831 survives and is now in the Science Museum London.