The Dutch National Aerospace Laboratory (NLR) has carried out windtunnel testing of a model of the NH Industries NH90 helicopter, aimed at evaluating the aircraft's infra-red signature during a range of flight conditions. The tests provided data on engine air-intake characteristics and exhaust- gas recirculation, while simulating the aircraft in forward, backward and sideways flight. The NH90 model was equipped with a dynamically scaled, 4.2m-diameter rotor, and allowed engine intake and hot exhaust flows to be evaluated simultaneously, says the NLR. Data on hub and blade loads, rotor-blade angles, air-intake and exhaust pressure-distributions and exhaust-gas and fuselage-skin temperatures were also acquired. The rotor blades were equipped with strain gauges to measure torsional bending loads, and provide on-line fatigue monitoring, says the NLR.
Source: Flight International
