Correlation of Puma airloads: Lifting-line and wake calculation

Abstract : A cooperative program, undertaken by organizations in the United States, England, France, and Australia, assessed the strengths and weaknesses of four lifting-line/wake methods and three CFD methods by comparing their predictions with the data obtained in flight trials of a research Puma. The Puma has been tested in two configurations: a mixed-bladed rotor with instrumented rectangular-tip and swept-tip blades, and a configuration with four identical swept-tip blades. The present paper examines the results of the lifting-line predictions. The better lifting-line methods show good agreement with lift at the blade tip for the configuration with four swept tips; the moment is well- predicted at 0.92 R, but deteriorates outboard. The predictions for the mixed- bladed rotor configuration range from fair to good. The lift prediction is better for the swept-tip blade than for rectangular-tip blade, but the reasons for this cannot be determined because of the unmodeled effects of the mixed- bladed rotor. Keywords: Helicopter flight test; Computational fluid dynamics; Helicopter airloads correlation; Helicopter rotors; Rotor blades rotary wings. (edc)

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