Test of an 0.8-Scale Model of the AH-64 Apache in the NASA Langley Full- Scale Wind Tunnel
ARMY AVIATION SYSTEMS COMMAND ST LOUIS MO
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This document summarizes the tests of an 0.8-scale model of the upper half of the AH-64 air vehicle in the NASA Langley full-scale tunnel, primarily to determine the large-scale blockage effects discovered during earlier tests of the same model in the NASA Langley 4- by 7-meter tunnel. As background information, and to provide continuity, the earlier program is outlined. The models were large and heavy, and therefore the balances had large capabilities. Yet, because of operational limitations with both wind tunnels involved, the only data that overlapped in flight conditions were at very low velocities. Thus, the results of these tests were inconclusive due to the time-honored difficulty of small differences in large numbers. This effect carried over into other, auxiliary test performed during the same test series, each concerned with an attempt to detect small differences.