The influence of dynamic inflow and torsional flexibility on rotor damping in forward flight from symbolically generated equationsThe combined effects of blade torsion and dynamic inflow on the aeroelastic stability of an elastic rotor blade in forward flight are studied. The Helicopter Equations for Stability and Loads (HESL) program is extended to derive the governing equations of motion for the blade, and a Lagrangian formulation is used to obtain the equations in generalized coordinates. The program generates the steady-state and linearized perturbation equations in symbolic form and then codes them into FORTRAN subroutines. The coefficients for each equation and for each mode are identified through a numerical program; the latter can also be used to obtain the harmonic balance equations. The governing multiblade equations are derived explicitly using HESL. These equations can accommodate any number of elastic blade modes. Stability results are presented for several hingeless rotor blade structural models, and the influence of dynamic inflow in forward flight with an elastic hingeless rotor is investigated.
Document ID
19860026427
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Reddy, T. S. R. (NASA Ames Research Center Moffett Field, CA, United States)
Warmbrodt, W. (NASA Ames Research Center Moffett Field, CA, United States)