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Factors Affecting Inlet-Engine Compatibility During Aircraft Departures at High Angle of Attack for an F/A -18A AircraftThe F404-GE-400 engine powered F/A- 18A High Alpha Research Vehicle (HARV) was used to examine the quality of inlet airflow during departed flight maneuvers, that is, during flight outside the normal maneuvering envelope where control surfaces have little or no effectiveness. A series of six nose-left and six nose-right departures were initiated at Mach numbers between 0.3 and 0.4 at an altitude of 35 kft. The yaw rates at departure recovery were in the range of 40 to 90 degrees per second. Engine surges were encountered during three of the nose-left and one of the nose-right departures. Time-variant inlet-total-pressure distortion levels at the engine face were determined to not significantly exceed those measured at maximum angle-of-attack and - sideslip maneuvers during controlled flight. Surges as a result of inlet distortion levels were anticipated to initiate in the fan. Analysis revealed that the surges initiated in the compressor and were the result of a combination of high levels of inlet distortion and rapid changes in aircraft motion. These rapid changes in aircraft motion are indicative of a combination of engine mount and gyroscopic loads being applied to the engine structure that impact the aerodynamic stability of the compressor through changes in the rotor-to-case clearances.
Document ID
19990024943
Acquisition Source
Armstrong Flight Research Center
Document Type
Technical Memorandum (TM)
Authors
Steenken, W. G.
(General Electric Co. Cincinnati, OH United States)
Williams, J. G.
(General Electric Co. Cincinnati, OH United States)
Yuhas, A. J.
(Analytical Services and Materials, Inc. Edwards, CA United States)
Walsh, K. R.
(NASA Dryden Flight Research Center Edwards, CA United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1999
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
NAS 1.15:206572
H-2327
NASA/TM-1999-206572
Funding Number(s)
CONTRACT_GRANT: NAS3-26617
PROJECT: RTOP 529-31-04-00-37
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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