Helicopters: Calculation and Design. Vibrations and Dynamic Stability

摘要

This book is volume two of Helicopters: Calculation and Design. In it are discussed certain questions of the theory of vibrations and methods of calculating stresses appearing during these vibrations. Methods of calculating structural service life are given, as well as methods of calculating vibrations of the helicopter, which allow the determination of the amplitude of these vibrations and their comparison with comfort norms. The problem of combined vibrations of the rotor and fuselage is examined for the first time in Soviet literature. The theory of self-excited oscillations of a special type, called 'ground resonance' is discussed in detail. Peculiarities of the appearance of such oscillations of the helicopter on land, during takeoff and landing and in flight. In a separate chapter there are examined special cases of the calculation of bearings operating in specific conditions of oscillatory motion. Here there is discussed the theory and method of the calculation of a new type of thrust bearing of increased load capacity and also bearings absorbing combined loads. (Author)