Aeroelastic Flutter Prevention in Gliders and Small Aircraft

Abstract

An empirical method is specified which can be used by the manufacturers of gliders and small aircraft to evaluate flutter vulnerability without extensive computational analysis and to take appropriate preventive measures. Suggestions are given on how designers can avert flutter from the very outset of the designing process. This method has been applied by the author in numerous cases and can be considered proven for conventional structures. It is based on the results of a simple vibration test as well as stiffness and friction measurements taken on the control system. Statistically derived design frequencies are given, thus restricting the number of vibration modes which must be considered. Through this method the required mass balance for the control surfaces is derived. Simple formulas for the calculation of the torsion frequency and the critical speed for torsional flutter are given.