NACA Technical Notes

From Introduction: "First, an analysis of loads transmitted to the hub by balanced blades will be given. In the second section, the additional loads transmitted to the hub in a direction normal to the plane of rotation of the blades by imbalances in a rotor are derived. In the entire analysis, the results are given in terms of the forces transmitted to the hub by a single rotating helicopter blade in flight, and these are regarded as known or given.

NACA Technical Notes

Note presenting an attempt to design the reinforcement of a cutout in a plane sheet in such a way that it is as nearly as possible equivalent to the part of the structure which has been cut out. A perfect equivalence would mean that the stresses and displacements of the structure remain the same as those which would have appeared without the cutout

NACA Technical Notes

Note presenting a theoretical study of the dynamic properties of lifting rotors, which includes the derivatives of the angles of attack of the inflow, blade-position variables, and aerodynamic and inertia forces, the development and solution of the equilibrium conditions of the blade system in the hovering and traveling states, and the development of the frequency, stability, and damping properties of the blades during hovering and traveling

NACA Technical Notes

Note presenting the frequency and damping characteristics of the coupled flagging and lagging oscillations of helicopter blades in hovering as derived for the general case in which the lagging (vertical) hinge axis is offset from the flapping hinge axis, while both hinge axes are inclined. An offset of the flapping hinge axis from the rotor axis of rotation is also considered