Note presenting an investigation of the icing characteristics and means of ice protection of a typical radial-engine cooling-fan installation. The icing of the unprotected cooling-fan installation was found to present a serious operational problem. Results regarding icing, steam heat de-icing, alcohol de-icing, and electrical heat de-icing are provided.

Note presenting the thermal performance of an air-heated propeller, installed on a test airplane, as evaluated by observations of the ice-prevention properties of the propeller during flight in natural icing conditions and by the collection of thermal data on the propeller during flight in clear air and in clouds at temperatures above freezing. The results indicated that the air-heated-propeller installation tested would offer little or no protection to the leading-edge regions of the propeller during flight in severe natural-icing conditions.

Report presenting an analysis of wind-tunnel data on the hinge-moment characteristics of control-surface tabs. Results regarding the correlation of section data, correlation of finite-span data, and effect of Mach number are provided.

Report presenting expressions for calculating the sideslip angles in certain maneuvers and numerical solutions for a wide enough range of variables to permit construction of design charts. Results regarding a comparison of flight and theoretical data and vertical-tail loads are provided.

"In conjunction with assumptions concerning the proportion of time spent at various speeds, statistical gust data were used to determine gust load factors that could be exceeded a given number of times during the operational life of an airplane. The results indicated that present gust load factors might be considerably lowered in certain cases with a consequent decrease in structural weight. Modification of the present criterion, however, must await the accumulation of data not presently available" (p. 1).

Report presenting a method for calculating wing characteristics by lifting-line theory using nonlinear section lift data. The wing characteristics calculated from general nonlinear section lift data have been found to agree much closer with experimental data in the region of maximum lift coefficient than those calculated on the assumption of linear section lift curves.

"Results of measurements are given as a supplement to earlier tests for a laminar profile with nose flap; magnitude, form, and angle of attack of the flap were systematically changed. The experiments were carried out at an effective Reynolds number of 8.2 x 10(exp 5). A comparison with measurements on other profiles shows that the effect of a nose flap is essentially dependent upon magnitude of the nose radius coefficient of the profile" (p. 1).

Report presenting measurements downwash angles behind a model of a high-aspect-ratio wing at points near the probable tail location at Mach numbers up to 0.89 in the high-speed tunnel. The model has an NACA 65-210 section, an aspect ratio of 9.0, a taper ratio of 2.5:1, no twist, dihedral, or sweepback. Results regarding experimental data and comparison of experimental and calculated results are provided.

Report presenting an investigation in the two-dimensional low-turbulence tunnels to develop optimum double-slotted-flap configurations for seven thin NACA airfoil sections. Each was equipped with the same flaps and measured at the same Reynolds numbers. Results regarding the lift characteristics and pitching moment are provided.

Report presenting comparative drag measurements at zero lift at transonic speeds for two sharp-leading-edge airfoils using the NACA wing-flow method. One airfoil had a symmetrical circular-arc section and one had a symmetrical double-wedge section. The primary difference in the drag characteristics of the two airfoils at zero lift is the earlier drag rise of the double-wedge section.

An investigation has been conducted in the Cleveland 18- by 18-inch supersonic tunnel at a Mach number of 1.85 and angles of attack from 0 deg to 5 deg to determine optimum design configurations for a convergent-divergent type of supersonic diffuser with a subsonic diffuser of 5 deg included divergence angle. Total pressure recoveries in excess of theoretical recovery across a normal shock at a free-stream Mach number of 1.85 wore obtained with several configurations.

"Results of tests of an airspeed head mounted on a freely falling body are presented in preliminary form. Measurements were made throughout the transonic speed range. Details and dimensions of the airspeed head and the body are given in figure 1" (p. 1).

Report presenting an investigation of a surge inhibitor that was able to cause a considerable gain in stable-airflow operating range over the range of equivalent impeller tip speeds tested. While the inhibitor was designed to triple the stable-airflow operating range, it increased it more than eight times its original value.

Report presenting an investigation of three transonic fuselage-inlet installations designed to maintain substream velocities on the body ahead of air inlets. Surface pressures and inlet total pressures were measured at the tops of the test configurations for wide ranges of inlet-velocity ratio and angles of attack. Results indicated that substream velocities were maintained on all three noses over the angle of attack ranges and inlet-velocity ratio useful for high-speed flight.

Report presenting an investigation of aileron flutter associated with high-speed flight. When the aileron control system was modified by installing a hydraulic irreversible unit, it was possible to delay aileron flutter and reduce its amplitude. Results regarding the aileron flutter with and without the modifications, analysis of the time histories for the control systems, and relation between aileron upfloat and flutter are provided.

Report presenting a method for calculating the drag, in a real compressible fluid and at subcritical Mach numbers, of airfoil sections at arbitrary life coefficients and of bodies of revolution at zero angle of attack. The values of drag coefficient are compared with values obtained for the same configurations by other methods. The differences between the results are found to lie withint he limits of accuracy of current experimental techniques.

Report presenting a procedure for calculating pressure distributions over airfoils at supercritical Mach numbers. Only the forward portion of the airfoil, where interaction between local boundary-layer thickness and local-pressure distribution is negligible, is considered in detail. The method cannot be considered definitive because it requires that certain characteristics regarding pressure distributions and geometric properties be known.

Report presenting a flight test of a supersonic research pilotless aircraft in which large-amplitude aileron oscillations, most likely aileron compressibility flutter, were encountered in the transonic and supersonic speed ranges. Results regarding power-on flight and coasting flight are provided.

Report presenting the air-flow behavior over the wing of an XP-51 airplane including photographs of tufts attached to the wing surface and chordwise pressure distributions. A comparison of tuft studies from flight results are compared with results from wind-tunnel testing. Three types of flow were observed: steady flow, unsteady flow, and break-away flow are provided.

Report presenting the drag of a series of complete airplane-like configurations and their components at transonic velocities using the free-fall method. The configuration tested in this report has a 45 degree sweptback wing of aspect ratio 4.1 mounted forward of the maximum diameter of a 10-inch-diameter body of fineness ratio 12 equipped with stabilizing tail fins. Results are presented as curves showing the variation of drag coefficient with Mach number for the complete configuration and for each component.

Report discussing the results of flight tests to determine the drag at zero lift of a swept-back wing of inverse taper using an NACA 65-009 airfoil. The data was compared to untapered wings with a similar degree of sweepback. The tapered wing was found to have a lower drag coefficient than the 34-degree swept-back untapered wing but a higher drag coefficient than the 45-degree swept-back untapered wing.

Report presenting the results of pressure-distribution tests to determine the effects of compressibility on the characteristics of the NACA 66,2-215, 66,2-015, 65(216)-418, 16-212, and 23015 airfoil sections. Schileren photographs of the air flow and data on the wake characteristics was also obtained.

Report presenting an investigation of surface static pressures over the outer and inner surfaces of the cockpit canopies on the Grumman F6F-3, Curtiss SB2C-4E, and Grumman F8F-1 airplanes in the full-scale tunnel. Results regarding the external pressure distribution and internal static pressure are provided.

Report presenting measurements of the behavior at supercritical Mach numbers of ailerons on a jet-propelled fighter plane. Results regarding aileron upfloat and aileron oscillations are provided.