Use of Multiblade Coordinates for Helicopter Flap-Lag Stability with Dynamic Inflow

Gaonkar, Gopal H and Peters, David A (1980) Use of Multiblade Coordinates for Helicopter Flap-Lag Stability with Dynamic Inflow. In: Journal of Aircraft, 17 (2). pp. 112-118.

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Abstract

Rotor flap-lag stability in forward flight is studied with and without dynamic inflow feedback via a multiblade coordinate transformation (MCT). The algebra of MCT is found to be so involved that it requires checking the final equations by independent means. Accordingly, an assessment of three derivation methods is given. Numerical results are presented for three- and four-bladed rotors up to an advance ratio of 0.5. While the constant-coefficient approximation under trimmed conditions is satisfactory for low-frequency modes, it is not satisfactory for high-frequency modes or for untrimmed conditions. The advantages of multiblade coordinates are pronounced when the blades are coupled by dynamic inflow.

Item Type:	Journal Article
Publication:	Journal of Aircraft
Publisher:	American Institute of Aeronautics and Astronautics (AIAA)
Additional Information:	Copyright of this article belongs to American Institute of Aeronautics and Astronautics.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	03 Feb 2010 09:10
Last Modified:	27 Dec 2010 08:44
URI:	http://eprints.iisc.ac.in/id/eprint/23193

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