Drucella Andersen
Headquarters, Washington, D.C.                                                         
April 1, 1992
(Phone:  202/453-8613)

Don Nolan
Ames-Dryden Flight Research Facility, Edwards, Calif.
(Phone:  805/258-3447)


RELEASE:  92-44

NASA SLATES SUPERSONIC PERFORMANCE AND CONTROL TESTS


      NASA will soon start supersonic flight tests of a new 
electronic control system that will  improve  the performance, 
reliability and safety of high-speed military aircraft, future 
commercial supersonic transports and the X-30 National Aero-Space 
Plane. 

      A NASA F-15 research aircraft will begin supersonic testing 
of the Performance Seeking Control in April 1992 at NASA's 
Ames-Dryden Flight Research Facility, Edwards, Calif.  The system 
monitors the plane's various computerized control systems in 
flight and automatically adjusts the combination of factors such 
as fuel flow and air flow into the engines to get the most thrust 
for the lowest possible revolutions per minute.

      Researchers expect Performance Seeking Control to produce 
about 9 percent greater thrust and 10 percent less fuel 
consumption in the F-15 when it cruises above the speed of sound.  
Subsonic research flights with the system in 1990 boosted the 
F-15's engine power by 15 percent, lowered fuel usage by 2 percent 
and reduced engine temperature by 160 degrees F.

      The improvements resulting from Performance Seeking Control 
have several benefits.  Lower engine temperature prolongs engine 
life; in the F-15, for example, every drop of 70 degrees F reduces 
the rate of engine wear by 50 percent.  The higher thrust shortens 
takeoff distance and lets fighter aircraft intercept a potential 
adversary more quickly.


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      The technology also could expand to become an indicator of 
wear on engine parts by measuring stress in the engine turbine 
area.  With normal preventive maintenance, the information could 
help insure fail-safe engine operation in high-speed aircraft.

      Performance Seeking Control applies to many aircraft, but 
future supersonic airliners would benefit most because the system 
would throttle back the engines to their lowest possible operating 
rates while the plane flies at sustained supersonic speeds.  The 
system also could be applied to the X-30 National Aero-Space Plane 
to integrate the X-30's various control systems.

      McDonnell Aircraft Co., St. Louis, Mo., and United 
Technologies Pratt & Whitney Division, West Palm Beach, Fla., will 
participate in the research program with Ames-Dryden.

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