Digital Computer Techniques For Engine/Airframe Simulation

Engine/airframe torsional-stability and dynamic-performance characteristics have been studied through digital computer simulations. Simulation techniques have been validated with both classical frequency-response and linear-simulation methods for stability predictions. Techniques for development of mathematical models of helicopter rotor and drive systems from representations similar to those proposed by ARP7041 are explained from application of F = ma equations to model presentation in the form of functional block diagrams. Mechanization of mathematical models into digital computer simulations with the Z-transform theory is described; a discussion of the analysis and development of Z-transform theory for digital simulations is also presented. Methods for performing frequency-response analysis and evaluation of engine/airframe torsional stability by both classical and simulation techniques are provided. Stability evaluations of nonlinear systems using simulation techniques are included, from the modeling of nonlinearities through the analysis of simulation data.