Report presenting a review of the status of instruments suitable for the measurement of the meteorological factors conducive to aircraft icing. Nine instruments which appear to be the most promising for obtaining meteorological data are discussed and recommendations for their continued use and development are provided.

Memorandum presenting a preliminary investigation made in the two-dimensional low-turbulence tunnel on an NACA 64A010 airfoil with permeable surfaces to obtain an indication of the stabilizing effect of area suction on the laminar boundary layer. Although the airfoil surface had many waves and irregularities of contour, the data corroborated qualitatively the theoretically predicted stabilizing effect of area suction on a smooth flat plate.

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.

Combustion chamber liners for gas turbines and experimental set-ups were tested for failure. A ceramic-lined test chamber was operated at fuel/air ratios up to 0.050. Thermal-shock evaluation indicated that a ceramic lining, which expands after firing, would crack but would not fall apart during operation. Refractoriness of the lining and the resistance to mechanical shock were adequate. In general, shell temperature reductions of approximately 400 deg F were effected by the use of this lining at fuel/air ratios of 0.016 and 0.050. The mechanism of failure of the ceramic lining was induced by sudden heating and cooling during operation.

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 information about some of the fundamental concepts and lines of development that may be undertaken regarding helicopter stability. Some of the principles discussed include method of control, control lag, stability characteristics, control forces, and center of gravity. Some of the means for improvement discussed include use of a horizontal stabilizer, use of trim devices, use of power-operated controls, automatic controls, and choice and grouping of indicating instruments.

Report presenting an investigation of a one-eighth segment of an annular combustor suitable for use as a component of an experimental turbojet engine. Due to the small space available for the combustor, a special design involving a minimum of obstructions in the combustion chamber was created. Results regarding the temperature-rise efficiency, total-pressure loss, and exhaust-gas temperature variation for several simulated engine operating conditions 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 discussing an aerodynamic control effectiveness study using free-flight, rocket-propelled test vehicles. Information about the effects of wing sweepback, aspect ratio, taper ratio, and section thickness ratio on the rolling effectiveness of full-span, sealed ailerons is provided.

Report presenting an extensive collection of lift and hinge-moment characteristics of control surfaces up to a Mach number of 0.90 in a high-speed wind tunnel. A wide variety of control-surface profiles, plan forms, and aerodynamic balances are included. Results regarding elevator hinge moments and longitudinal control, aileron hinge moments and lateral control, control-surface characteristics, and transonic flutter are highlighted.

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.

Memorandum presenting the results of a wind-tunnel investigation of the low-speed characteristics of horizontal tails of aspect ratio 3 with unswept and swept-back plan forms. Two models were tested which had identical areas, aspect ratio, taper ratio, and airfoil section, differing only in the angle of sweepback and elevator area ratios. The major effect of sweepback was to increase the rate of change of hinge-moment coefficient with angle of attack, to reduce the rate of change with elevator deflection, and to reduce the elevator effectiveness.

From Summary: "The effects of externally mounted rockets and fuel tanks on the aerodynamic characteristics of an airplane model with a swept-back wing are presented in this report."

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.