PREFACE TO DYNAMICS SERIES The aim of these data sheets and memoranda is to provide@ in a form convenient to designers and others@ information relating to dynamics. The results of much valuable work@ both theoretical and practical@ are frequently not applied because they are buried in a large number of technical reports and papers which designers have not the time to discover nor to read. In addition@ much information exists which has never been published. It has been the task of the Aerodynamics and Performance Committee to monitor the work of the Engineering Sciences Data Unit in preparing data sheets and memoranda to assist designers in these two disciplines. Both Committees had become aware@ over many years of their operation@ that neither was adequately covering the field of dynamics@ although some data sheets in both Series dealt with certain aspects. Accordingly@ in 1961@ they jointly recommended that a Dynamics Committee be appointed to examine published and unpublished information@ to correlate experimental data@ to assess theoretical predictions and to issue@ in the form of data sheets or memoranda@ the best information available in the light of present knowledge.