A technique for the automatic, digital analysis of flight dynamic response data

Abstract

A technique is described for using a digital computer for the extraction of aerodynamic force and moment derivatives from measurement of the motion of aircraft or aircraft models, following a disturbance from the trimmed state. The analysis method is based on model matching by least squares using an automatic iterative method and has been found capable of handling coupled three-dimensional motions of much greater complexity than it has been possible to analyse previously. The particular problem of solution divergence which limits the usefulness of iterative methods has been overcome, giving a virtually fully-automatic system for response analysis that can be applied to a wide range of aircraft-like problems. A full description is given of the use of the techniques for the analysis of dynamic response data from free flight models. However, few modifications would be necessary to the computer programs for application to full-scale aircraft tests and even dynamic stability tests in windtunnels.