Hawker Siddeley P1154
The Hawker Siddeley P.1154 was essentially a larger, faster, more powerful version of the Harrier concept. The P1154 was launched as a common aircraft for the Navy and the Royal Air Force. The P 1154 was considered in the first place as a Hunter replacement for the Royal Air Force and possibly as a Sea Vixen replacement for the Royal Navy. It was not easy to find an aircraft which is light enough and at the same time powerful enough to be able to carry out the dual rôles of replacing both the Hunter and the Sea Vixen. The research and development cost was appallingly high.
The P 1154 was to be a revolutionary V.T.O.L. supersonic fighter. It was to replace the RAF's Hunter, which was outclassed by the aircraft held by such countries as Indonesia and Iraq. The Hunter would have gone out of service about 1968-69. In regard to the P 1154, which was to be its replacement, the requirement was sent out in 1960; contract study was ordered in November, 1962; authorisation for the more advanced research and development was made in February 1964.
Hawker Aircraft at Kingston began design work in early 1961 on a stretched, supersonic derivative of the P.1127, under the direction of Ralph Hooper. Designated P.1150, this used a Pegasus engine incorporating plenum chamber burning (PCB) in the bypass air delivered to the front nozzles. During August 1961 Hawker received specification AC/169 for a supersonic V/STOL strike fighter to meet NATO Basic Military Requirement 3 [BMR-3]. Seven countries presented eleven projects. Four were down-selected - the Dassault Mirage III-V, Fokker-Republic D.24 Alliance, BAC 584 and Hawker's P.1154, a P.1150 derivative with the BS.100 engine giving greater mission performance. Hawker submitted their proposal in January 1962. The evaluations showed that no project answered the NBMR-3 completely. However, two projects of very advanced design, Hawker P1154 (the United Kingdom) and Dassault Mirage III V (France) were retained, but the countries did not manage an agreement on the choice of one or the other formulae. The results of the competition were announced in May 1962 - the P.1154 won the technical competition while the Mirage III-V was viewed as better in terms of industrial work share; the two aircraft were joint winners.
The Hawker P1154 was an aircraft based on using the same engine for lift and propulsion. The concept of the P1154 was from the beginning based on the BS100 engine of the Bristol Siddeley Company, which pioneered this type of engine. Rolls-Royce, at a very late stage, submitted proposals for developing a twin version of the Spey for this aircraft, but this option was rejected. The impressive BS100 powerplant was to have a thrust in excess of 35,OOOlb, and its development is being partially financed througi the Mutual Weapons Development Program. The aircraft used PCB (plenum chamber burning) a kind of reheat system used directly into the cold airflow of the forward nozzles. This made the aircraft supersonic and gave it a rapid climb rate.
Several versions were planned: a single seat RAF strike aircraft, a two seat Naval strike anti shipping variant, a two seat trainer and a single seat interceptor/ground attack aircraft [this was the final version offered to the Royal Navy]. The air force and navy couldn't agree on the requirements for the aircraft, which created problems, since the contractor needed the airframe to have as much commonality as possible to make production viable. The preliminary brochure submitted in August 1962 saw the RAF and Royal Navy aircraft as being 80% common. By the time of the more detailed brochure of May 1963 the situation was reversed, with only 20% commonality between the two designs.
By 1963 the large number of V/STOL vehicles under development around the world indicated that the field was just now beginning to be exploited, and that there seemed to be a nearly infinite number of things V/STOL aircraft might do. However, they can not do all of these things well nor can they necessarily do them better than some other type of vehicle. The problem was to find the right vehicle for each job. This type of research - finding the right vehicle - seemed destined to continue in the V/STOL field for many years to come.
By 1963 the role of the aircraft carrier was to be close support for an opposed landing, and especially the deployment of fighter aircraft. This took no account of the development of the vertical take-off fighter, the P1154. Proponents argued that this machine spelled the death knell of the big aircraft carrier. Such a machine, taking off and landing vertically, could be operated from the decks of a tanker, or a depot ship, or a fleet auxiliary, or a passenger ship, or a cargo ship. Therefore, the Royal Navy would not need big aircraft carriers. Proponents argued that it must be accepted that in less time than it will take to build an aircraft carrier fighters will be jumping off vertically, and it must also be accepted that bombers are shore-based; and surely the ground attack and close support aircraft will usually be last year's fighters. Perhaps if sufficient time had passed since the P1154 became operational, the P1154 itself will in due course become the ground attack machine and do light bombing or rocketeering or whatever is required.
The design and operational characteristics worked out during 1964 were embodied in specification SR250D, issued in October. The P.1154 submitted to this specification had a length of 57ft 6in [versus 43 ft 6 in for the P1127], span of 28ft 4in [versus 23 ft 10 in for the P1127] and height of 12ft 6 in [versus 11 ft 9 in for the P1127]. The low aspect ratio, 269 sq. ft wing used a 'peaky' aerofoil, with a leading edge sweep of 41.2 degrees. The airframe was stressed to 7.5g for combat and 3g for ferry missions. The aluminium and titanium structure was designed for a 3,000hr fatigue life. Empty weight of the P.1154 was projected as 20,100 lb, maximum loaded weight being 40,050 lb in the ferry condition [versus 9,800 lb and 12,401-15,501 lb, respectively, for the P1127].
By 1964 it emerged that to develop a second version of the P1154 for the Royal Navy would, on best estimate, have added a formidable bill — over £100 million — to what would have to be spent if the UK bought from overseas the relatively small number of aircraft required. That is why the Government began investigating the possibility of buying the Phantom aircraft from the United States to meet the Royal Navy, as distinct from the Royal Air Force, requirement. The noble Earl, Lord Jellicoe, when he was First Lord of the Admiralty [or he may have been then Minister of Defence for the Royal Navy] managed to get authorisation for the buying of the Phantom in place of the Sea Vixen. And yet the Sea Vixen came into service five years later than the Hunter.
The American Phantom would replace the British P.1154 for the Navy. Development of the latter as the Hunter replacement was going ahead, and this will bring important design and production work to the industry. What happened was that the Navy could not see a way to meeting the Navy's requirement for a Sea Vixen replacement with a variant of the P.1154. It would be extremely costly to develop a separate Sea Vixen replacement for such a limited requirement with no apparent export prospects. On the other hand, the Phantom was already in production, and could be fitted with Rolls Royce engines, thus making a considerable contribution to employment in this country. The engine content of the aircraft represents around 1/3 of its total value.
On taking office in the autumn of 1964, the incoming Labour administration was electorally and ideologically committed to a thorough review of defence policy and defence expenditure. However, there were other, more more pressing, reasons. First, there was ample evidence that British forces were overcommitted and underequipped. Second, the reforms introduced into the central organisation for defence by the Conservative administration had still to be completed. And last, the economic situation was such that overall defence expenditure would have to be reviewed in relation to necessary cuts in public expenditure.
By early 1965 the estimated research and development and production costs of the P1154 had continually risen over the past three years. Research and development costs had trebled and yet this was still at a very early stage of development. All experience, unfortunately, led to the belief that the escalation in costs would continue. It was also a question of time-scale. The P1154 was still at least six years away from squadron service and it would have been — and that is assuming, again, that there would have been no further delay in development — about eight years before all our squadrons were re-equipped with this aircraft. Yet the P1154 was supposed to replace the Hunter, which entered service as long ago as 1954 and which was ageing fast.
In London, 10,000 British. aircraft workers marched on 13 January 1965 to protest the rumored intention of the Labour Government to curtail production of British military planes. Defense Minister Denis Healey reportedly recommended that development and production of the TSR-2 (tactical strike- reconnaissance) aircraft be canceled and that Britain buy F-lll’s from U.S., thus cutting defense costs. Two other projects subject to cancellation were the P-1154 vertical-takeoff fighter and a short-takeoff fighter, both at a less advanced stage of development than the TSR-2. Leaders of the British aircraft industry, which employed slightly more than one per cent of the nation’s work force, said such a cutback would cause widespread unemployment in the industry.
Prime Minister Harold Wilson announced on 03 February 1965 plans to buy American military aircraft to replace British aircraft, an action he said would save more than $840 million over a 10-yr. period. The two U.K. projects being dropped were the P-1154 vertical take-off supersonic strike aircraft and the HS-681 short take-off military transport. Both were made by the Hawker Siddeley group. American Phantom II’S, made by McDonnell Aircraft, would be ordered to replace the P-1154. Phantoms were already on order to replace the Royal Navy’s Sea Vixens. Lockheed’s C-130’s would replace the HS-681. The American planes would be equipped with British engines. On the question of the TSR-2, which the U.K. was considering replacing with General Dynamics’ F-111, Mr. Wilson said there was not enough information yet to make a final decision.
As announced in February 1965 the P.1154 could not possibly have been in service before 1970–71 and might well have been later. But critics charged that while with the Sea Vixen replacement there was no alternative save the Phantom, there was a perfectly good alternative in the case of the Hunter — the P1154. The RAF version could not have been ready before 1972. Faced with the position that the P1154 was unacceptable, the had to look for alternative aircraft and it decided on a mixture of the American Phantom and the British Kestrel, the P1127. As of 1966 payments to date on the P1154 had been £20 million.
The essence of the requirements of the P 1154 was to try to combine in one aircraft supersonic performance with a vertical and short take-off and landing capability. In this respect the P 1154 was unique. But it has had to be rejected on grounds of time and cost.
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