Background and Principles of Throttles-Only Flight Control. Electronic Workshop Presentation, Research Engineering, NASA Dryden Flight Research Center

Burcham Jr., Frank W. (1995) Background and Principles of Throttles-Only Flight Control. Electronic Workshop Presentation, Research Engineering, NASA Dryden Flight Research Center.

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Abstract

There have been many cases in which the crew of a multi-engine airplane had to use engine thrust for emergency flight control. Such a procedure is very difficult, because the propulsive control forces are small, the engine response is slow, and airplane dynamics such as the phugoid and dutch roll are difficult to damp with thrust. In general, thrust increases are used to climb, thrust decreases to descend, and differential thrust is used to turn. Average speed is not significantly affected by changes in throttle setting. Pitch control is achieved because of pitching moments due to speed changes, from thrust offset, and from the vertical component of thrust. Roll control is achieved by using differential thrust to develop yaw, which, through the normal dihedral effect, causes a roll. Control power in pitch and roll tends to increase as speed decreases. Although speed is not controlled by the throttles, configuration changes are often available (lowering gear, flaps, moving center-of-gravity) to change the speed. The airplane basic stability is also a significant factor. Fuel slosh and gyroscopic moments are small influences on throttles-only control. The background and principles of Throttles-Only flight control are described in this paper.

EPrint Type:	Other
Keywords:	Propulsion-only control, Performance seeking control, F-15 HIDEC, Propulsion systems, Integrated flight-propulsion control, Flight test
Subjects:	Aircraft/Project: F-15 HIDEC (01 - 09) Aeronautics: (05) Aircraft Design, Testing And Performance Aircraft/Project: F-15 PSC
ID Code:	1860
Deposited On:	20 March 2008
Additional Information:	11 pages. Presented at an Electronic Workshop held at Edwards, California, 1993. Published in NASA TM-104278 "An Electronic Workshop on the Performance Seeking Control and Propulsion Controlled Aircraft Results of the F-15 Highly Integrated Digital Electronic Control Flight Research Program: Proceedings of the Electronic Workshop," pages 159-169, 1995. Burcham Jr., NASA Dryden Flight Research Center.