Comparison of Predicted and Experimental Rotor Loads to Evaluate Flap‐Lag Coupling with Blade Pitch
Abstract:An analylical model far the prediction of rotor performance and structural loads has been developed to include time‐dependent variations in blade stiffness using a modal approach. Comparison of predicted rotor loads with wind tunnel rotor test results revealed the importance of using coupled modes and of choosing the most appropriate eoordinstc system to satisfy the hypothesis of time‐invariant mode shapes. The decision to employ modes that are either defined in hub or blade axis coordinates is discussed in relation to various rotor configurations. Further rotor load comparisons are presented for a distinctly different rotor using Lynx flight data. In this case, the inclusion of time‐varying structural coupling between flap and lag motions demonstrated an improved capabilily to predict the magnitude and phase of chordwise bending moments.
Document Type: Research Article
Affiliations: Westland Helicopters, Yeovil, Somerset, England
Publication date: 1979-10-01
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