MEASUREMENT OF AERODYNAMIC DAMPING AND STIFFNESS DERIVATIVES IN FREE OSCILLATION WITH AUTOMATICALLY RECYCLED FEEDBACK EXCITATION

摘要

A dynamic test technique for obtaining the aerodynamic damping and stiffness derivatives is described. The technique is based on the method of free oscillation and it employs automatically recycled feedback excitation. The technique has been found to be very convenient, fast and accurate and is of particular interest for tests in intermittent wind tunnels because of its very efficient use of the short running times available.nThe technique is presented here together with a description of an experi¬mental apparatus for oscillation-in-pitch tests on half models, where it was first used. The same technique can be used, of course, for any single degree-of-freedom oscillation experiment.