Helicopter Application Studies of the Variable Deflection Thruster Jet Flap

摘要

The results of an analytical study to determine the application of a blown flap device called the Variable Deflection Thruster (VDT) to a helicopter rotor are presented and analyzed. The study is part of a longer-range program to investigate and develop control techniques for stabilization of the higher harmonic modes of helicopter rotor blades. A high-speed digital computer program was used to calculate the aerodynamic characteristics and performance of a Sikorsky CH-34 rotor system as though equipped with a blown two-dimensional section. The study was made over a range of rotor flight profiles and operating parameters including advance ratio, shaft angle of attack, blade pitch, tip Mach number, jet deflection angle and blowing rate. Performance of the blown rotor is compared to the conventional CH-34 rotor to illustrate VDT application effectiveness. Results show that the operating lift capability and propulsive force of the CH-34 rotor are increased when the rotor is equipped with a blown device. A preliminary analysis of the attenuation of rotor hub-shear variation by programmed blowing is also shown. In all cases, improved performance through application of blown control requires additional power. (Author)