SIGHTINGS


 
Military Jets To Get Amazing
New Vectored Thrust System
By Jon Pratty
www.telegraph.co.uk
2-16-99
 
 
NASA has begun testing a radical new flight control system for military jets that develops the vectored thrust principle pioneered in the British Harrier jump-jet.
 
The new vectored thrust system enables almost impossibly tight turns and climbing manoeuvres and will eventually be used in a new generation of super-agile American fighters. The first of these, rumoured to be called Project Aurora, would be a contender to use the vectored thrust system first.
 
The F15 "Active" fighter marries a new F100-PW-229 engine with a special digital control system, called Inner Loop Thrust Vectoring, or ILTV. The engine in the otherwise conventional looking fighter is key to the advance: it has long deflector blades attached to the rear that deflect thrust up to 20 degrees off the centre line of the aircraft. These thrust deflectors are digitally connected to the pilot's joystick and are permanently part of the control system he uses.
 
"The airplane displays outstanding flying qualities in all thrust vectoring modes," said Nasa project manager Berwin Kock at Dryden Flight Research Centre, Edwards, California. Nasa test pilots use a handling rating system called the Cooper-Harper Index and the new fighter was given ultra-high ratings of grade one or two for its handling right from the first flight.
 
"Most test pilots are very reluctant to give a Cooper-Harper rating of one," said research pilot Jim Smolka, "because it means that the aircraft is perfect, that there is nothing the pilot can find that needs to be improved. The fact that all of the pilots agreed that the flying qualities deserve ratings of one and two means that the aircraft really has exceptional handling."
 
Nasa is not the first to develop thrust vectoring. Russian designers have built a series of Sukhoi fighters, culminating in the recent Su37 TVC, which showed that it could perform impossible-looking somersaults in mid-air using its thrust vectoring control system.





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