Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/A-18 Aircraft

Brenner, Martin J. (1996) Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/A-18 Aircraft. Technical Report NASA TP-3647, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

An F/A-18 aircraft was modified to perform flight research at high angles of attack (AOA) using thrust vectoring and advanced control law concepts for agility and performance enhancement and to provide a testbed for the computational fluid dynamics community. Aeroservoelastic (ASE) characteristics had changed considerably from the baseline F/A-18 aircraft because of structural and flight control system amendments, so analyses and flight tests were performed to verify structural stability at high AOA. Detailed actuator models that consider the physical, electrical, and mechanical elements of actuation and its installation on the airframe were employed in the analysis to accurately model the coupled dynamics of the airframe, actuators, and control surfaces. This report describes the ASE modeling procedure, ground test validation, flight test clearance, and test data analysis for the reconfigured F/A-18 aircraft. Multivariable ASE stability margins are calculated from flight data and compared to analytical margins. Because this thrust-vectoring configuration uses exhaust vanes to vector the thrust, the modeling issues are nearly identical for modern multiaxis nozzle configurations. This report correlates analysis results with flight test data and makes observations concerning the application of the linear predictions to thrust-vectoring and high-AOA flight.

EPrint Type:	NASA Technical Publication
Keywords:	Aeroservoelasticity, Aircraft vibration, Dynamic stability, F/A-18 aircraft, Flight dynamics, Structural dynamics, Thrust vectoring
Subjects:	Aircraft/Project: F-18 HARV (01 - 09) Aeronautics: (08) Aircraft Stability And Control
ID Code:	184
Deposited On:	15 July 2004
Additional Information:	64 pages.