Flight test for H-V diagram determination of a TH-500 helicopter equipped with a new main rotor blades

Authors
Maj. Raffaele DI CAPRIO, Flight Test Engineer, Italian Air Force Flight Test Center - Reparto Sperimentale Volo, Italy
Maj. Nicola PECILE, Experimental Test Pilot, Italian Air Force Flight Test Center - Reparto Sperimentale Volo, Italy

Abstract

A flight test program was executed for the military qualification of a new main rotor blade model for the TH-500 helicopter. Within the test program, part of the test flights were aimed to gather the required data to determine the height-velocity diagram in a clean configuration of the helicopter. In this frame, several actions were implemented in order to allow for test flight time/costs saving and for safety improvements. In particular, the explored H-V diagram was based on both analytic and off-line simulation predicted curves; moreover, a flight test technique was used where full autorotations were executed only for the most critical test points on the border of the predicted envelope. The test results obtained were used to define new helicopter limitations and normal and emergency procedures to be included in the rotorcraft flight manual. This paper discusses, among all things, how the pilot workload was one of the driving factors considered by the evaluating crew in order to clear the new H-V envelope in a safe and reliable manner.