Hawker Siddeley P.1154
The Hawker Siddeley P.1154 was a planned supersonic
Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...

 vertical/short take-off and landing
Vertical and/or short take-off and landing is a term used to describe aircraft that are able to take-off or land vertically or on short runways. Vertical takeoff and landing describes craft which do not require runways at all...

 (V/STOL) fighter aircraft designed by Hawker Siddeley Aviation (HSA). Developed alongside the subsonic and smaller Hawker Siddeley P.1127/Kestrel, the P.1154 was derived from the P.1150. The P.1150 proposal did not meet NATO Basic Military Requirement 3 and, consequently, the P.1154 was born. This Mach
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...

 2-capable platform retained plenum chamber
Plenum chamber
A plenum chamber is a pressurised housing containing a gas or fluid at positive pressure . One function of the plenum can be to equalise pressure for more even distribution, because of irregular supply or demand...

 burning previously designed for the P.1150. Although the technical winner out of eleven submissions, follow-on testing and production for the P.1154 did not proceed as a result of political strife.

Meanwhile, HSA considered modifying the airframe for a joint specification for an aircraft by the RAF and Royal Navy. Between 1961 and 1965 the two services harmonised their specifications to preserve design commonality. However, the RAF's desired configuration was to take precedence over that of the Royal Navy's. A number of proposals were submitted – at one stage, a twin-Spey design was considered, then rejected. Following the Labour government
Labour Party (UK)
The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after...

's coming to power in 1965, the project was cancelled. The Royal Navy would acquire the F-4 Phantom, while the RAF continued to foster development of the P.1127 (RAF), leading to the successful Harrier
Harrier Jump Jet
The Harrier, informally referred to as the Jump Jet, is a family of British-designed military jet aircraft capable of vertical/short takeoff and landing operations...


NATO requirements

In 1961, during the development of the V/STOL P.1127 and Kestrel, HSA considered the feasibility of a supersonic V/STOL aircraft. This was influenced by a general perception at the time that supersonic aircraft held significantly more value than subsonic aircraft. Consequently, on 13 April 1961, HSA decided to conduct preliminary work on a supersonic P.1127 under the guidance of Ralph Hooper. The aircraft, designated P.1150 and 50% larger than the P.1127, would employ plenum chamber
Plenum chamber
A plenum chamber is a pressurised housing containing a gas or fluid at positive pressure . One function of the plenum can be to equalise pressure for more even distribution, because of irregular supply or demand...

 burning (PCB) – essentially an afterburner in the previously cold forward nozzles – in the engine. The engine was a Pegasus
Rolls-Royce Pegasus
The Rolls-Royce Pegasus is a turbofan engine originally designed by Bristol Siddeley, and now manufactured by Rolls-Royce plc. This engine is able to direct thrust downwards which can then be swivelled to power a jet aircraft forward. Lightly loaded, it can also manoeuvre like a helicopter,...

 development named the BS.100, and had four swivelling exhaust nozzles. The front nozzles were equipped with PCB, which uses the same principle as an afterburner
The AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, portablemonopoly.net was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...

, allowing the aircraft to theoretically reach speeds of Mach 1.7–2.
The design effort was initially undertaken to cater for NATO Basic Military Requirement 3 (NBMR.3), which was issued in August 1961. Specifications called for a supersonic V/STOL strike fighter with a combat radius
Combat radius
Combat radius refers to the distance from an airbase that a warplane can reach, patrol there for a set amount of time and return to base with minimal fuel left, thus completing a combat mission...

 of 250 nautical miles (463 km). Cruise speed was to be Mach 0.92, with a dash speed of Mach 1.5. The aircraft, with a 2000 pounds (907.2 kg) payload, had to be able to clear a 50 feet (15.2 m) obstacle following a 500 feet (152.4 m) takeoff roll. However, as requirement specifications changed, the aircraft was considered undersized; subsequent studies confirmed these fears, and so Bristol enlarged the original PCB engine and raised the exhaust heat to increase thrust to 146.8 kN (30,000 lbf). A new larger design emerged, initially named P.1150/3 before being redesignated the P.1154.

NBMR.3 also attracted ten other contenders, among which was P.1154's principal competitor, the Dassault Mirage IIIV
Dassault Mirage IIIV
|-See also:-Bibliography:* Breffort, Dominique and Andre Jouineau. "The Mirage III, 5, 50 and derivatives from 1955 to 2000." Planes and Pilots 6. Paris: Histoire et Collections, 2004. ISBN 2-913903-92-4....

. This design employed a separate lift/thrust engine concept whereby eight Rolls-Royce engines would provide lift, with a single Turboméca Atar for thrust. The Mirage IIIV was supported by British Aircraft Corporation
British Aircraft Corporation
The British Aircraft Corporation was a British aircraft manufacturer formed from the government-pressured merger of English Electric Aviation Ltd., Vickers-Armstrongs , the Bristol Aeroplane Company and Hunting Aircraft in 1960. Bristol, English Electric and Vickers became "parents" of BAC with...

. HSA submitted its design to NATO through the Ministry of Aviation
Ministry of Aviation
Ministry of Aviation was a department of the United Kingdom government, established in 1959. Its responsibilities included the regulation of civil aviation and the supply of military aircraft, which it took on from the Ministry of Supply....

 (MoA) on 8 January 1962 and, in May that year, the P.1154 emerged as the winner in the competition for the NBMR.3 over the Mirage IIIV. The P.1154 was judged to be technically superior, however the Mirage was politically palatable due to the cooperative development and production across member nations. The project was terminated in 1965 after the French government subsequently withdrew following the selection of the P.1154 over the Dassault design.

RAF and Royal Navy requirements

On 6 December 1961, before the design was submitted to NATO, it was decided that the P.1154 would be developed with the requirements for use by both the RAF and the Royal Navy. In February 1962, the Royal Navy's Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 received the aircraft concept with great interest as the Royal Navy was seeking a new interceptor aircraft
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...

 for their aircraft carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

s. As a single aircraft, the P.1154 would replace Hawker Hunter
Hawker Hunter
The Hawker Hunter is a subsonic British jet aircraft developed in the 1950s. The single-seat Hunter entered service as a manoeuvrable fighter aircraft, and later operated in fighter-bomber and reconnaissance roles in numerous conflicts. Two-seat variants remained in use for training and secondary...

s of the RAF and the de Havilland Sea Vixen
De Havilland Sea Vixen
The de Havilland DH.110 Sea Vixen was a twin boom 1950s–1960s British two-seat jet fighter of the Fleet Air Arm designed by de Havilland. Developed from an earlier first generation jet fighter, the Sea Vixen was a capable carrier-based fleet defence fighter that served into the 1970s...

s of the Fleet Air Arm
Fleet Air Arm
The Fleet Air Arm is the branch of the British Royal Navy responsible for the operation of naval aircraft. The Fleet Air Arm currently operates the AgustaWestland Merlin, Westland Sea King and Westland Lynx helicopters...

 (FAA). However, the services sought different characteristics in their aircraft – the RAF desired a single-seat fighter with secondary intercept capability, while the Royal Navy wanted a two-seat interceptor capable of secondary low-level strike capability.

Although financially and politically committed to a joint requirement with the Royal Navy, the RAF's single-seat design took precedence over the two-seat version of the Royal Navy. However, RAF P.1154s would have to accommodate the Navy's large airborne intercept (AI) radar. When HSA submitted the design on 8 August, the Royal Navy criticised the proposal, which had a tandem undercarriage layout incompatible with catapult operations; consequently, a tricycle undercarriage
Tricycle gear
Tricycle gear describes an aircraft undercarriage, or landing gear, arranged in a tricycle fashion. The tricycle arrangement has one wheel in the front, called the nose wheel, and two or more main wheels slightly aft of the center of gravity...

 design was investigated and accepted as practical. In December that year, Rolls-Royce offered a PCB-equipped vectored thrust twin-Spey design as an alternative. This was seen as inferior, however, and was not considered in great detail. The aircraft required PCB for vertical takeoff, but this caused significant ground erosion. The aircraft would have been armed with the Red Top missile.

With the RAF and Royal Navy requirements diverging, the aircraft's development started to stumble. While modifications towards naval requirements had been made, by July 1963 weight gain had become a considerable issue, and the Navy was openly criticising the choice of V/STOL. However, despite a stated Navy preference for a swing-wing
A variable-sweep wing is an aeroplane wing that may be swept back and then returned to its original position during flight. It allows the aircraft's planform to be modified in flight, and is therefore an example of a variable-geometry aircraft....

 fighter, on the 16 July 1963 the services agreed that the aircraft would be completely common, with the exception of different radar systems. By August 1963 Hawker Siddeley was expressing the view that range of changes made were damaging the aircraft's potential for export. At the same time, the Navy stated that it regarded the P.1154 as a second-rate interceptor, and the RAF openly decried the loss of strike performance. By October 1963, the MoA was concerned with the project's progress, and noted that the effort to combine a strike aircraft and a fighter in a single aircraft, and trying to fit that same airframe to both of the services, was "unsound".

Disfavour and cancellation

In November 1963, the RAF still found the P.1154 to be a suitable platform, while the Royal Navy appeared to consider the McDonnell Douglas F-4 Phantom II a better fit for its needs. In response, Hawker Siddeley focused its efforts on the RAF version. On 26 February 1964, it was announced in the House of Commons by the Conservative government that a development contract had been placed for the P.1154, equipped with the BS.100 engine, as an RAF strike aircraft. At the same time it was announced that the Naval requirement would be met by Spey-engined Phantoms. More positive news emerged in 1964; on 30 October the BS.100 engine ran for the first time and Hawker Siddeley received favourable reports that the P.1154 was competitive with the performance of other aircraft, including the F-4 Phantom II.
However, on 2 February 1965, the incoming Labour government
Labour Party (UK)
The Labour Party is a centre-left democratic socialist party in the United Kingdom. It surpassed the Liberal Party in general elections during the early 1920s, forming minority governments under Ramsay MacDonald in 1924 and 1929-1931. The party was in a wartime coalition from 1940 to 1945, after...

, led by Harold Wilson
Harold Wilson
James Harold Wilson, Baron Wilson of Rievaulx, KG, OBE, FRS, FSS, PC was a British Labour Member of Parliament, Leader of the Labour Party. He was twice Prime Minister of the United Kingdom during the 1960s and 1970s, winning four general elections, including a minority government after the...

, cancelled the P.1154 on the grounds of cost, along with several other aircraft such as the BAC TSR-2
The British Aircraft Corporation TSR-2 was a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation for the Royal Air Force in the late 1950s and early 1960s...

 strike aircraft and Hawker Siddeley HS.681
Armstrong Whitworth AW.681
|-See also:-External links:*...

 VSTOL transport. At the time of cancellation, at least three prototypes were under construction. Following the cancellation, the RAF and Royal Navy adopted the F-4 Phantom II instead, but the government also gave a contract for continued work on the P.1127 (RAF), which led to the Harrier; this name had originally been reserved for the P.1154 should it enter service. In retrospect, aviation author Tony Buttler considered the cancellation of the aircraft to be justified, noting the time consuming and expensive failures of attempts by other nations (such as Soviet/Russia's Yak-41
Yakovlev Yak-141
The Yakovlev Yak-141 , also known as the Yak-41, is a supersonic vertical takeoff/landing fighter aircraft designed by Yakolev. It did not enter production.-Design and development:...

 and West Germany's EWR VJ 101
EWR VJ 101
-See also:-Bibliography:* Rogers, Mike. VTOL: Military Research Aircraft. New York: Orion Books, 1989. ISBN 0-517-57684-8.* Winchester, Jim. "EWR-Sud VJ 101C ". X-Planes and Prototypes. London: Amber Books Ltd., 2005. ISBN 1-904687-40-7....

) at a supersonic VTOL aircraft.

Specifications (P.1154 – RAF version)

See also

External links

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