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Accession Number:
ADA564738
Title:
Effects of Torsion Frequencies on Rotor Performance and Structural Loads with Trailing Edge Flap
Descriptive Note:
Corporate Author:
ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND MOFFETT FIELD CA AVIATION AEROFLIGHT DYNAMICS DIRECTORATE
Report Date:
2012-07-24
Pagination or Media Count:
14.0
Abstract:
The effects of variation of blade torsion frequency on rotor performance and structural loads are investigated for a 1rev active flap rotor and baseline rotor no active control. The UH-60A four-bladed articulated main rotor is studied at a high-speed forward flight condition. The torsion frequencies are varied by modifying the spanwise torsional stiffness of the blade andor the pitch link stiffness. First, a parametricoptimization study on the flap deployment schedule is carried out using lifting-line comprehensive analysis for the soft, baseline, and stiff rotor configurations, and then a higher fidelity coupled computational fluid dynamics, computational structural dynamics analysis is carried out for the optimal flap deployment. It is shown that with the soft rotor there is degradation in performance of about 6 with respect to the baseline rotor in the case where the flaps are not activated, and of about 1 if flap deflections are applied. On the other hand, for the stiff rotor there is a slight improvement in performance of about 2.3 when the flaps are not activated, and no appreciable change in the case where active flap deflections are applied. It appears that the peak performance achievable with using active flaps on a baseline stiffness rotor cannot be further improved significantly by varying the torsional frequencies. Variation of torsion frequency does not appear to have a significant influence on blade torsion moments and pitch link loads, although the 1rev flap activation examined has an important role.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
