FLIGHT-TESTING AMATEUR-BUILT HELICOPTERS

Flight-test procedures for the amateur-built helicopter are presented. Test methods were collected from acceptable practices for flight-testing Normal Category Rotorcraft, Amateur-Built Aircraft and Ultralights. Some practices were modified for the limitations of in-flight instrumentation and piloting experience. A significant modification of procedures was to establish a methodology of flight-testing using collective control stick position as an indicator of power during performance testing. Additionally, testing of stability and control can benefit from these procedures too. In-flight test data of a United States Army OH-58 was “reduced”, analyzed and used to verify the relationship between collective position and engine shaft horsepower required (ESHPreq), which could be used to provide a means of estimating power usage. The test results showed the correlations between the predicted ESHPreq and the actual in-flight ESHPaval when the airspeed was between 90 knots. The recommendation is that these test methods be adopted by the Experimental Aircraft Association (EAA) for supervised field-testing of amateur-built helicopters with limited instrumentation.