Report discusses the results of force testing of the aerodynamic characteristics of an NACA 0009 airfoil with a double plain flap; it consisted of a plain forward flap with a chord 20 percent of the airfoil chord and a plan rearward flap with a chord 15 percent of the airfoil chord. Comparisons were made to the characteristics of a 0.50c single plain flap. The lift, hinge moments, drag, and pitching moments are described.

Report presenting a series of tests of the Brewster XSBA-1 airplane conducted to determine the effect of various tail modifications. The current report describes an investigation of flying qualities of the airplanes with its original tail surfaces. Testing regarding longitudinal stability and control and stalling characteristics are provided.

Report presenting values of the lateral-stability derivative, the rate of change of yawing-moment coefficient with yawing angular velocity, contributed by the wing, the fuselage, and the vertical tail, which have been determined for a midwing airplane model by the free-oscillation method.

Report presenting vibration tests of a four-blade single-rotating propeller operating in a simulated pusher condition performed because the combination of wake and downwash behind a wing might provide serious excitation for reactionless vibrations of propellers with four or more blades. Measurements of propeller vibratory stress were made for various airspeeds, engine speeds, and engine powers.

Report describes a procedure for instrumenting, testing, and presenting the overall characteristics of any engine turbosupercharger installation. The preflight analysis of the system, required testing, importance of accurate data recording, measurements to record, methods of measuring, and presentation of results are also included.

Report presenting an investigation to determine the effects of wing loading and altitude on lateral stability and control in the free-flight tunnel. The results of flight tests of the model were correlated with calculated stability boundaries, and an effort was made to determine for each loading condition the airplane configuration that gave the best flight characteristics. Results regarding the lateral stability, lateral control, and general flight behavior are provided.

Report discussing testing to determine the effect of a horizontal tail on the lateral-stability characteristics of a high-wing, a midwing, and a low-wing monoplane. The model was created from a circular fuselage, an NACA 23012 tapered wing, and an NACA 0009 horizontal tail surface. Information about the effective aspect ratio of the tail, restoring moment of yaw, and vertical-tail effectiveness as compared to the wing position is provided.

Report presenting porpoising tests of three rudimentary models composed of two V-bottom planing surfaces in tandem and fitted with a tail plane. The upper and lower branches of the upper trim limit of stability were determined for three angles of dead rise and two depths of step.

Report presenting testing made with simplified models of two types of hulls that differ considerably from conventional types. Both have a single main planing surface that is combined with after-planing surfaces placed directly below the aerodynamic tail surfaces. Results regarding an investigation of twin planing tails, a single-planing tail, and potentialities indicated by tests are provided.

Report presenting results of mechanical tests of macerated phenolic molding material. The following tests were performed: static tension, compression, torsion, and flexure tests; long-time creep tests at different stresses, tests for time to fracture under long-continued constant load; Izod and Charpy impact tests; bending fatigue tests at different ranges of stress; rotating-beam fatigue tests at different speeds of testing; rotating beam fatigue tests of notched specimens; and torsion fatigue tests.

"This report presents the results of systematic model experiments on the hydrodynamic characteristics of flying boats, aimed primarily at developing a comprehensive view of the factors influencing porpoising and of their relative importance. The experiments 'radiated' from a given reference ship; they embrace changes, over reasonably wide ranges, in the value of each of a number of variables, treated independently. The experimental results are summarized in a series of 25 figures, each of which gives the complete data for all the modifications of one variable" (p. 1).

Report presenting the results of an investigation of the fatigue characteristics of spot-welded 24S-T aluminum alloy. The static shear strength of spot welds in lap joints of 24S-T alclad increases with increasing sheet thickness for thicknesses in the range of 0.025 inch to 0.032 inch.