An Inlet Distortion Assessment During Aircraft Departures at High Angle of Attack for an F/A-18A Aircraft

Steenken, William G. and Williams, John G. and Yuhas, Andrew J. and Walsh, Kevin R. (1997) An Inlet Distortion Assessment During Aircraft Departures at High Angle of Attack for an F/A-18A Aircraft. Technical Report NASA TM-104328, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

The F404-GE-400-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. 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 entry yaw rates were approximately 40 to 90 deg/sec. 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 did not significantly exceed those at maximum angle-of-attack and sideslip maneuvers during controlled flight. Surges caused by inlet distortion levels resulted from a combination of high levels of inlet distortion and rapid changes in aircraft position. These rapid changes indicate a combination of engine support 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. This document presents the slides from an oral presentation.

EPrint Type:	NASA Technical Memorandum
Keywords:	Aircraft departures, Engine stability limits, F/18-18A airplane, High angle of attack, Inlet distortion
Subjects:	Aircraft/Project: F-18 HARV (01 - 09) Aeronautics: (07) Aircraft Propulsion And Power
ID Code:	133
Deposited On:	07 June 2004
Additional Information:	32 pages. W.G. Steenken and J.G. Williams, General Electric Aircraft Engines, Cincinnati, OH. A.J. Yuhas, AS&M, Inc., Edwards, CA. Kevin R. Walsh, NASA Dryden Flight Research Center, Edwards, CA. Oral presentation given at the NASA High-Angle-of-Attack Technology Conference, NASA Langley Research Center, Hampton, VA, September 17–19, 1996.