A comparison of helicopter recovery maneuvers on frigates by means of PIV measurements

Abstract

"Helicopter pilots who have to operate on frigates must deal with turbulent and unsteady flows caused by the incidence of the wind on the non-aerodynamic surfaces of the frigate. In addition, the flight deck is usually placed at the stern, right behind the frigate superstructure where recirculation and low-velocity regions appear. For that reason, studying how the aerodynamic effects influence the helicopter rotor during the approach and landing on the frigate could be essential to guarantee safe operations. The aim of this paper is to present PIV velocity maps with the flow patterns generated by the interaction between the frigate wake and the helicopter rotor working during its landing approach usually named as dynamic-interface. Three different landing maneuvers have been analyzed: rear, diagonal and aft-fore. The jet generated by the rotor will be used to obtain induced velocity profiles under the rotor. With these velocity profiles, rotor asymmetries during its working over the frigate are detected. With all data at each point of the maneuvers, a final comparison will be made to select the best procedure for helicopter recovery on frigates under different wind over deck conditions."