Hawker Siddeley P.1154
A key difference of this design was the addition of plenum chamber burning, essentially an afterburner-like arrangement in the thrusters used during hover, greatly increasing their thrust.
During the late 1950s, Hawker Siddeley Aviation (HSA) was keen to develop a new generation of combat aircraft that would be capable of supersonic speeds.
[1] Recognising the need to promptly commence work on another development program, HSA's chief aircraft designer Sir Sydney Camm, who had been in regular discussions with Sir Stanley Hooker of Bristol Aero Engines, decided that the company should investigate the prospects of developing and manufacturing a viable combat-capable vertical take-off and landing (VTOL) fighter aircraft.
[2] While HSA chose to go ahead with the P.1127 as a private venture, the Air Staff disagreed heavily over what requirements should be set out for a future RAF VTOL aircraft; some officers, such as the Chief of the Air Staff Sir Thomas Pike, advocated simplicity while others, such as the RAF operational requirements division, sought various performance demands of such an aircraft, particularly the capacity for supersonic flight.
[7][8] The P.1150 proposal broadly resembled its P.1127 predecessor despite major changes being made, including its revised fuselage, the adoption of a thinner wing, and an advanced version of the Pegasus engine.
[12] HSA formed an agreement with the German Focke-Wulf aircraft company to collaborate on a joint study that looked into the issue of equipping the P.1150 with two additional lift engines.
This was a blow directly felt not only by HSA and the development team, but by the British Air Ministry, who had been also seeking to collaborate with its West German counterparts on the VTOL aircraft.
[12] Meanwhile, further studies served to confirm fears the P.1150 would be too small to meet customer specifications, so Camm initiated work on an enlarged derivative design.
In conjunction with HSA's redesign, Bristol worked to enlarge the original PCB engine and raise the exhaust heat to increase thrust to 146.8 kN (30,000 lbf).
[15] While the P.1154 was judged to be technically superior, the Mirage acquired a greater level of political palatability due to the co-operative development and production aspects proposed for the programme, which spread work across a number of member nations.
[15] By March 1962, the Ministry of Defence was openly interested in the potential for the P.1154 being adopted as a replacement for both the RAF's fleet of Hawker Hunters and the Royal Navy's de Havilland Sea Vixens.
[12] Accordingly, in April 1962, a first draft of a new joint Naval/Air Staff requirement was issued in the form of Specification OR356/AW406, to which HSA had submitted a response by June of that year.
[21] In order to perform a vertical takeoff, the use of PCB was necessitated; however, this feature would have come at the cost of significant ground erosion during operations.
[19][24] In December 1962, HSA dedicated its full effort to developing the RAF's single seat variant; Wood notes the starting point for which was broadly similar to the proposal submissions for NBMR-3.
[25] However, as HSA carried out further work on the detailed design phase of the programme, it was becoming clear that opinions on the internal equipment for the aircraft varied substantially between the two services.
[26] Despite a stated Navy preference for a swing-wing fighter, the services agreed that the aircraft would be completely common, with the exception of different radar systems.
[15] By August 1963, HSA was openly expressing the view that the range of changes being made to the aircraft was damaging its potential for export sales.
[22] By October 1963, according to Wood, the situation had become critical and some officials were beginning to examine alternative options, such as conventional fighter aircraft in the form of the McDonnell Douglas F-4 Phantom II.
[28] Around this point, the Royal Navy expressed their open preference for the F-4 Phantom II and soon Thorneycroft conceded that the service would get this aircraft instead, and that development of the P.1154 would continue to meet the RAF's requirement.
Wood described the overall situation as: "From start to finish the P.1154 programme was a story of delay, ministerial interference and indecision... the P.1150 would now be the ideal aircraft for the new generation through-deck cruisers"[24] Data from The British Fighter since 1912[32]General characteristics Performance Armament
