Aerodynamic performance of the winged helicopter applying upper surface blowing

Powered-lift technology applied to vertical takeoff and landing aircraft can generate high lift coefficients. The determination of how this high lift capability can be utilized to improve rotary-wing aircraft performance, and thereby unload the rotor, is obtained by estimating the amount of additional lift produced, as well as the effect of the powered-lift technique on rotor speed.

This thesis discusses the particular case of the winged helicopter applying upper- surface-blowing technology. A theoretical approach, supported by actual wind tunnel test results, is used to investigate the helicopter vertical drag compensation.

Furthermore, mathematical relations and plots are generated to illustrate the effect of flap deflection angle on additional lift, and also the effect of angle of attack on rotor speed at different settings of the blowing coefficient and the flap deflection angle.

Finally, this thesis shows how the upper-surface-blowing technique can also be utilized to improve the propulsive capability of the helicopter.