BOOK REVIEWS2 767 Report No. 441, A Flight Investigation of the Spinning of the NY-I Airplane with Varied Mass Distribution and Other Modifications, and an Analysis Based on Wind-Tunnel Tests, by Nathan F. Scudder, 18 pages, illustrations, 23 X 29 cms. Washington, Superintendent of Documents, I932. Price ten cents. This report presents the results of an investigation of the spinning characteristics of the "NY-I" naval training biplane. The results of flight tests and an analysis based on wind-tunnel test data are given and compared. The primary purpose of the investigation was the determination in flight of the effect of changes in mass distribution along the longitudinal axis, without change of mass quantity or centroid.
The effect of varied mass distribution was to decrease the angle of attack and the linear and angular velocities, as ballast was moved from the center of gravity to the nose and tail of the airplane, without shift of centroid. Moderate changes in wing loading and dihedral of the wings and comparatively large changes in center-of-gravity position have small effects on the spin under the conditions of the tests. Different settings of ailerons and elevator altered the nature of the spin but did not bring about recovery, which was effected only by the rudder.
The tests showed that full-down deflection of the elevator alone increased the rate of rotation, indicating that recoveries could best be made by using the rudder before moving the elevator down. Removal of a large portion of the fin and rudder covering (above the stabilizer and elevator) had no appreciable effect on the spin. A reasonable agreement was obtained between flight results and a numerical analysis, although the method of the analysis neglected many of the minor factors that usually are thought to influence the spin.