Results of a wind tunnel test on advanced rotor confleuratlons Dresent an assessment of the benefits of advanced airfoils, tip shape, blade chord, and blade number. A C H -4 7~ model rotor with VR-7/8 airfoils was tested as a reference rotor. The advanced rotors incor~oratine recently-develo~ed VR-12/15 hieh meed airfoils.--.were tested to 231 knots in the wind tunnel and demonstrated an improvement of 6.0% in figure of merit and 25% in cruise lift-to-efferlive-dmg ratio over a rotor with VR-7/8 airfoils. The advanced airfoib show slpnifirant improvements in stall inception limits, n)inp qualilirr houndurier and rotor noise. Improved h1.d~ tip shupes prtevide addilional benefits in rotor noiqe and do not reduce theslall inception hosndar). Thecc rerulls demonstrate a significant advance in conventional rotor capability, and indicate further improvements that can be gained from planform-structural tailoring and further development of airfoils, specifically for high speed rotor operation.

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