METHOD FOR DETERMINING THE PHENOMENON OF STALL ON HELICOPTER BLADE

Abstract

The analysis of dangerous factors leading to the phenomenon of flow stall on the rotor blades of a helicopter has been carried out. The estimated cruising speed of a helicopter without auxiliary propulsion at the current level of technology development lies in the range of 280-370 km/h. The results of flight experiments showed that the stall phenomenon leads to a sharp increase in the load on the blades, which in turn is transferred to the lower fixed plate of the swashplate. This phenomenon is accompanied by the appearance of the n-th harmonic of the main rotor speed. The results of these experiments made it possible to create a subsystem for recognizing the phenomenon of stall with the issuance of visual and audible indication to the pilot to change the flight mode. A block diagram and description of the operation of the subsystem based on the simultaneous use of two features are given: measurement of mechanical stresses on the swashplate and the amplitude of the harmonic component of the signal from the frequency of rotation of the rotor blades of the helicopter. The use of two signs can significantly increase the probability of determining the moment of flow stall. The technical implementation of the proposed method for determining the phenomenon of flow stall on the rotor blades of a helicopter makes it possible to provide a qualitatively new level of flight safety under conditions of complex maneuvers.