Accession Number : ADA184287

Title :   Effect of Planform Taper on Hover Performance of an Advanced AH-64 Model Rotor.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER

Personal Author(s) : Kelley,Henry L.

Report Date : AUG 1987

Pagination or Media Count : 12

Abstract : The hover performance of a 27-percent-scale model baseline rotor and advanced rotor with a 3:1 tapered tip (TR3) for the AH-64 attack helicopter was investigated in the rotor test cell at the Langley 14- by 22-foot Subsonic Tunnel as part of ongoing efforts to improve rotorcraft efficiency. The hover performance of the baseline rotor was compared with that of the TR3 rotor and with that of a previously tested advanced rotor with 5:1 tapered tip (TR5). Rotor thrust in hover at a rotor height-to-rotor diameter ratio of 1.46 was varied over a range of thrust coefficients for rotor tip Mach numbers of 0.63 and 0.57 respectively. The rotor with the TR3 blades had improved hover performance as compared with the rotor with the TR5 blades, and both the TR3 and TR5 blades were superior to the baseline rotor in terms of figure of merit for the range of thrust coefficients from 0.0020 to 0.0100. The additional margin in performance for the TR3 blades as compared with the TR5 blades was likely due to an increase in blade area and Reynolds number at the blade tip region brought about by the change in taper ratio from 5:1 to 3:1.

Descriptors :   HELICOPTER ROTORS, TEST AND EVALUATION

Subject Categories : Helicopters

Distribution Statement : APPROVED FOR PUBLIC RELEASE