COOCH MEMORIAL LECTURE – 22nd November, 1985.
“Harrier – a unique British Engineering Adventure.”
by Dr. J. W. Fozard O.B.E., F.Eng.
The President chaired this lecture which was delivered at Worthing Central Library. He introduced the speaker who is currently the Director of Special Projects, Weybridge Division of British Aerospace. Starting at the age of fifteen with Blackburn Aircraft Ltd., he has been intimately involved with the engineering and development of V/STOL (vertical/short take-off and landing) aeroplanesin particular the Harrier, including thirteen years as Chief Designer.
He first outlined the early attempts in 1956-7, to show the practicability of vertical take-off of a jet propelled sub-sonic fighter. The aim was. of course, to achieve the operational advantages of a helicopter in not requiring airfields having vulnerable long runways whilst retaining as much as possible of the combat performance of the jet fighter. The Hawker engineers demonstrated their P1127 in a tethered test at Dunsfold in i960 but these “initial precarious hovers” were generally regarded merely as yet one more of the twenty five or thirty V/STOL prototypes and generated no special excitement
in the hearts and minds of the Naval Staffs and Air Staffs of the day.
Yet Hawkers continued their development work and overcame many technical problems with some Government support but only polite interest, from the military. With the first full flight demonstration in September 1961 and design of the Hawker Pl^^ in 1962 showing the first practical supersonic vectored-thrust fighter as a possibility the Air and Naval Staffs became more positively interested. In 1963 the P1127 demonstrated the first-ever jet V/STOL flights from a ship – H.M.S. Ark Royal.
After political attempts to rec icile the Naval and Air Force requirements in a common design failed, the supersonic design was dropped and the P1127 was re-designed and in 1967 appeared as the “Harrier”.
The Harrier GR1 entered service with the R.A.F. in 1969 and a two seater version was developed for training. About this time the United States Marine Corp decided that the Harrier, with some modifications, would meet their needs and between 1971 and 1976 over one hundred entered service, as support planes in amphibious landings.
The Royal Navy were determined to have their own air defence and in 1975, after protracted political difficulties, ordered 2k Harriers on a fixed price contract. The first Sea-Harrier flew in 1979* Dr.
Fozard gave some convincing statistics showing the success of the Harrier GR/3 of the R.A.F. and the Sea Harriers during the Falklands Campaign. Harriers have proved capable of up to ten sorties/day/aircraft as against boasts of three for non V/STOL fighters.
As regards the engineering principles, this V/STOL plane uses a jet fan engine propelling the plane through rotateable nozzles.
When the nozzles point downwards the plane is lifted upwards and as they ar> rotated towards the pointing-seaward position the vertical (lift) component of the-force decreases and horizontal (propulsion) component increases – the latter produces air speed and thus lift from the wings to replace that lost from the jets. When take-off using a short run is used a greater load can be carried than with vertical take-off because of the addition of lift from the wings.
The Pegasus engine has a two-stage compressor: the input stage is a low pressure compressor feeding a nozzle on each side of the plane and also feeding into the high pressure stage. The high pressure air passes through the combustion chamber into the turbine and thence to the rear two nozzles, one on each side of the plane. All shafts are concentric but the two compressor rotors rotate in opposite directions to cancel gyroscopic effects. The four nozzles all turn together, under pilot control, from vertical to horizontal to produce the vectored thrust .-
Because the Harrier has normal wings and tail assembly it flies and is controlled as a jet fighter. When hovering, and at low speeds, control is effected through a reaction control system (RCS). This is a system of controllable air jets or valves at the wing tips and fore/ aft of the fuselage.
The intended super-sonic V/STOL aeroplane was to obtain the extra power by the addition of fuel burners into the two forward nozzles, calledPCB (Plenum chamber burning.)
In the mid 19?0’s the ski-jump take-off technique was evolved and demonstrated at Farnborough Air Show in 1978. The end of a ships runway is ramped at a slope of up to 12 degrees and the upward velocity imparted to the plane with a short take-off run then allows a 30% increase in pay load, or alternatively a reduction in runway total length from l80m to 60m. Alternatively the deck run can be traded for ship speed, e.g. elimination of the need to turn into the wind.
Dr. Fozard showed clearly the operational advantages of the V/STOL capability, now demonstrated in active service – army, navy and amphibious. Some possibilities currently influencing service thinking are (a) the greater use of small aircraft carriers e.g. Hermes, Ark Royal of 20,000 t, compared with the U.S. giants of 80,000 t (b) the use of commercial container ships after rapid conversion when needed by addition onto the superstructure of containers fully fitted out for aircraft servicing, crew quarters etc. The V/STOL aircraft operate from the deck – the Atlantic Conveyor used in the Falklands Campaign showed the way. Dr. Fozard calls this SCADS – shipbourne containerised air defence system.
(c) the Skyhook method of launch and recovery of V/STOL aircraft from ships. The hook is suspended from a crane mounted on the ship and stabilised against ships roll and the plane hovers under the hook for capture and is then swung down to the deck.
The talk showed the exceptional quality of the innovative engineering of the Harrier by engineers of British Aerospace and the project/ marketing skills they used in convincing military and naval men of the operational advantages. Slides and the several film sequences shown were admirable.
The Chairman, on conclusion said his ideas about.flying were now considerably changed – but ‘seeing is believing’. He called on Mr. Hulbert, who in expressing the appreciation of the meeting said the Chinese have a saying – ‘tell me and I forget, show me and I may remember, involve me and I will understand.’ This paper, he said, was so well presented and illustrated that we could almost feel we were involved in the project. As engineers we would all have come across the official inertia.
COOCH MEMORIAL LECTURE – 22nd November, 1985.