An Analytical Study of a Multicyclic Controllable Twist Rotor

A rotor employing a servo-flap to effect blade torsional deflections (the Kaman Controllable Twist Rotor) has been used in a theoretical study to assess the potential of multicyclic flap control, i.e., 1P, 2P, 3P, and 4P flap deflections. The results show virtual elimination of pylon vibratory loads may be achieved with concurrent blade bending moments reduced by 50 %. The amplitude requirements of the higher harmonic deflections are of the order of 3 or 4°. The study is in two parts; the calculation of rotor loads for specific combinations of multicyclic flap deflections by a typical rotor computer analysis, and an analysis of those results to determine optimum combinations of the multicyclic flap control. The paper discusses the analysis and indicates the potentials of a multicyclic controllable twist rotor.