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Aerospace Engineering Online: Technology update - Advancing STOVL
Error 404--Not Found
From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:
10.4.5 404 Not Found
The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent. If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.
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Error 404--Not Found
From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:
10.4.5 404 Not Found
The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent. If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.
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Technology update
Advancing STOVL
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DERA's VAAC Harrier making an aircraft carrier "ski-jump" takeoff.
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An extensively modified, research-dedicated Harrier operated by the Defence Evaluation Research Agency (DERA) in the UK has been selected by the American/UK Joint Strike Fighter (JSF) program to carry out further trials in Advanced Short Takeoff and Vertical Landing (ASTOVL) control law development for shipboard operations. DERA operates a Vectored Thrust Aircraft Advanced Flight Control (VAAC) two-seat Harrier said to be the most capable system available for the study of control concepts for powered-lift aircraft. The VAAC Harrier is equipped with a digital flight control system described by the agency as offering advanced, programmable fly-by-wire (FBW) capabilities from the rear seat. The result gives the pilot full-authority digital control of the aircraft, allowing programmable computer simulations of different flying modes to be developed and installed, according to DERA. The controls determine a flightpath via a computer interface. The work with the VAAC will build on previous DERA/NASA research into advanced control laws but will represent the first comprehensive shipboard evaluation. The aircraft made a successful FBW landing on a British aircraft carrier last year.
New trials are aimed at reducing the developmental risk of the JSF STOVL flight control system as the program enters the EMD (engineering, manufacturing and design) phase next year. In January last year, pilots from the U.S. and UK took part in a JSF research exercise to assess various control modes. Although five were Harrier pilots, four had no experience in flying this type of aircraft. The aim was to develop simpler STOVL flying using two levers instead of the regular Harrier's three. By April last year, software had been developed to allow rolling takeoffs, in addition to vertical, within a full STOVL envelope.
DERA said that the aircraft's digital flight control system has three key implications. First, it allows the testing of different flying modes in real-flight environments; modifications to the software and the flying experience can be swiftly and easily accommodated between flights with the significant benefit of incorporating pilot feedback almost instantaneously; and it offers STOVL capability without the need for the tricky third nozzle control lever, thus significantly improving flying simplicity. DERA added that the use of mechanical detents and computer feedback to lodge the stick and throttle holds the VAAC Harrier at existing speed, bank altitude, climb, dive angle, hover height, sideslip direction, descent, and ascent to give hands-free flying. The integrated approach is regarded as benefiting the JSF program in several aspects, including the capability for simpler, carefree handling that simplifies training, a reduction in the risk of pilot error, and an increase in pilot/airframe performance through the optimal use of controls.
Stuart Birch
Aerospace Engineering April 2000
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Error 404--Not Found
From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:
10.4.5 404 Not Found
The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent. If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.
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