Experimenting Rotorcraft Flight in Complex Environmental Conditions Using the Wind Tunnel: Helicopter Ship Landing Case

This paper presents an experimental approach to study the aerodynamic loading of a scaled helicopter model while strongly affected by the environmental conditions. The landing scenario over the deck of a simplified ship geometry has been considered where the aerodynamic interaction between rotor inflow and ship airwake results in additional workload for the pilot. First, the flow field of the isolated-ship was studied by means of pressure measurements and Particle Image Velocimetry in various wind conditions. Then, the aerodynamic loads of the rotor was measured for a wide range of wind velocity, direction and position of the rotor over the deck. In addition to the time-averaged measurements, the frequency spectrum of the thrust and in-plane moments were obtained over the low-frequency range of interest for the flight mechanics and pilot workload. Furthermore, to understand the effect of the approach velocity, a fully dynamic landing maneuver was performed so that the results, in terms of unsteadiness of the aerodynamic loads, can be compared with the common approach of static way-points.