The Aerodynamic Effect Of An Oblique Wind On Helicopter Recovery To The Queen Elizabeth Class Aircraft Carrier

Abstract

This paper describes an investigation into the air flow over the flight deck of HMS Queen Elizabeth, the UK's new aircraft carrier, and how it could affect helicopter recovery. The twin islands on the starboard side of the ship mean that there will be turbulent air flow over the flight deck for starboard winds. The unsteady air flow over the ship was created using time-accurate Computational Fluid Dynamics for a 25kts wind coming from 25° off the starboard, i.e. a Green 25 wind over deck. As well as using the CFD results to show the expected mean velocity field and turbulence intensity over the flight deck, the time-varying velocity components have also been used to assess how the unsteady air flow will affect a helicopter by integrating the velocity components of the ship’s airwake with a flight dynamics model of a helicopter configured to represent a SH-60B Seahawk. The application of the helicopter flight dynamics model has been implemented in two different ways: first where the flight model is held stationary in the airwake to evaluate the unsteady aerodynamic loads imposed on the helicopter, and second where the airwake and the flight model are integrated into a piloted full-motion flight simulator to assess pilot workload during a series of deck landings. The results show how the turbulent air flow over the landing spots correlates with the predicted unsteady loads on the helicopter, and with the workload ratings awarded by a test pilot in the simulator.