A small-scale tiltrotor model was tested in the 7- by 10-Foot Wind Tunnel at NASA Ames Research Center with the goal of further investigating the aerodynamic environment of a tiltrotor operating in the Vortex Ring State (VRS). Test objectives were to obtain performance data of a 3-bladed tiltrotor model over a range of descent and sideslip conditions and to compare mean thrust results with a previously reported 2-bladed tiltrotor model investigation. Three sets of rotor blades, twisted and untwisted, were tested in a dual rotor configuration. Results of this investigation are presented, showing mean thrust reductions, a reduction in the effective lift curve slope and an increase in required collective pitch in the region of VRS. There was no consistent trend between the 2-bladed and 3-bladed untwisted blade sets or the two sets of twisted blades. Sideslip did not appear to significantly effect mean vehicle thrust.
展开▼
