Air Stability Analysis Of A New Side-by-side Helicopter

The air stability problem of helicopter, also known as “air resonance”, is one of the basic problems of helicopter dynamics, which would jeopardize flight safety and must be resolved in the design process. In this thesis, the flight stability of rotor-wing-fuselage coupled system of a new type side-by-side helicopter is studied. Having new hub configuration and a new way to manipulate the rotor, there are no flapping hinge and lead lag hinge on the blade of the new type side-by-side helicopter and only the pitch hinge is kept. When manipulated, the rotor hub with a gimbal tilts with blades as a whole, so the hub configuration and manipulation is simpler comparing with traditional single-rotor helicopter and tiltrotor aircraft.Divided into the fuselage, elastic wing and the rotor, based on Hamilton’s principle, using multi-body method to describe the relationships among the positions and movements of the various components, the semi-span dynamic model of rotor-wing-fuselage coupled system of the new type side-by-side helicopter is established and contrasted with the results of similar model. Based on the model, the stability in hover of the new type side-by-side helicopter is studied by analyzing eigenvalues. Then the effects of various parameters on the stability are analyzed, including the beam bending stiffness, the chord bending stiffness and the axial torsion stiffness of the wing, hub manipulation stiffness, blade pitching stiffness and flight speed. Some conclusions are gotten from the analysis which can provide some reference to the future study and design of the new type side-by-side helicopter.