DEVELOPMENTAL FLIGHT TESTING OF THE SECOND GENERATION COMPOSITE BLADES (CMRBII)

The second generation composite main rotor blades (CMRBII) for Kaman’s SH-2G helicopter have been successfully designed, developed, and tested. The CMRBII retains the 10,000+ hour fatigue life and excellent repair-ability of the first generation blade. The CMRBII is less complex than the earlier blade and is economically producible, even in limited quantities. Four CMRBII blades were whirled on the test rig to ensure proper mass and c.g. distribution before conducting the flight testing. Three aircraft gross weights and three fuselage drag configurations were tested. The 4/rev vibration levels of CMRBII blades were acceptable with vibration level decreasing as bank angle increases. CMRBII blades have approximately 3 to 5% better OGE hover performance and a slightly better stall margin than the metal blade. In addition, CMRBII blades need very light boost-off flight cyclic control forces and provide excellent flying qualities and cyclic control sensitivity. The entire flight test program was conducted within a two week time period in a very effective manner. Initial analytical and whirl test rigging did not require alteration.