CALCULATION OF LOADS ON THE CONTROLS WITH HELICOPTER MAIN ROTOR OF SINGLE-ROTOR DESIGN

Abstract

The article describes the method of calculation of the moments about the hinge axis of the main rotor hub from the action of aerodynamic and inertial forces generated on the blade. The assumptions were taken that the blades are absolutely rigid and have a rectangular shape in plan view. Flapping motion of blade is described accurately up to the first harmonic of the Fourier series, inductive speed is considered to be uniformly distributed over the rotor disk.The aerodynamic component of hinge moment is numerical integration of running forces on blade radius taking into account aerodynamic characteristics of the profiles received according to wind tunnel tests at different angles of attack and Mach numbers. The moment from elastic forces is determined for the main rotor hub with the lamellar torsion bar. On the basis of the hinge moments values data loads on rotorcraft rotating ring, arising at different azimuthal location of the rotating main rotor blades are calculated.The calculations executed on the example of Mi-34 helicopter main rotor have shown that average loads in one revolution in the channel of collective pitch control increase in a control path at flying speed. At the same time loads in the channel of longitudinal control make up to 80 % of loads in the channel of collective pitch control, and in the channel oflateral control - to 40 % that will well be coordinated with the provided data of flight tests.