AirDyn - An Airwake Dynamoneter. Developing an instrument for measuring the effect of ship airwakes on helicopter operations

Piloting a maritime helicopter onto a ship's landing deck can be fraught with difficulties and dangers. Part of the reason is the degraded visibility and a confined landing area, as well as the ship motion and poor low-speed landing qualities. However, another source of difficulty is the unsteady airflow over the ship's superstructure, i.e. the airwake. As the helicopter rotor moves into the airwake as it separates from the top and sides of the hangar, the rotor thrust and moments vary significantly making the helicopter difficult to control. This proposal is concerned with developing an instrument that will measure the effect of this flow field on a model helicopter. The research aims to develop a new Airwake Dynamometer (AirDyn) capable of measuring aircraft loads, including pitch and roll moments. These can then be correlated with measurements of the velocity field over the landing deck, and with pilot experience in the Liverpool flight simulator. The intention is to use the AirDyn and turn our attention not just to the problem of why airwakes affect helicopter stability and pilot workload, but how the airwake can be modified to alleviate the effects, and possibly attract the helicopter to its landing spot.