From Summary: "A preliminary investigation of the stalling processes of four typical airfoil sections was made over the critical range of the Reynolds Number. Motion pictures were taken of the movements of small silk tufts on the airfoil surface as the angle of attack increased through a range of angles including the stall. The boundary-layer flow also at certain angles of attack was indicated by the patterns formed by a suspension of lampblack in oil brushed onto the airfoil surface. These observations were analyzed together with corresponding force-test measurements to derive a picture of the stalling processes of airfoils."

Report presenting a flight investigation to determine the contributions of wing, tail, and fuselage to the total airplane lift of a propeller-driven fighter-type airplane. The tests occurred over a range of Mach numbers. The loads on the various airplane components were measured by the use of calibrated strain-gage installations located at the roots of the wings and horizontal tail surfaces.

From Summary: "An analysis is given of the oscillating motion of a ballistic missile which upon entering the atmosphere is angularly misaligned with respect to the flight path. The history of the motion for some example missiles is discussed from the point of view of the effect of the motion on the aerodynamic heating and loading. The miss distance at the target due to misalignment and to small accidental trim angles is treated. The stability problem is also discussed for the case where the missile is tumbling prior to atmospheric entry."

A simplified analysis of the velocity and deceleration history of missiles entering the earth's atmosphere at high supersonic speeds is presented. The results of this motion analysis are employed to indicate means available to the designer for minimizing aerodynamic heating. The heating problem considered involves not only the total heat transferred to a missile by convection, but also the maximum average and local time rates of convective heat transfer.

Report presenting calculations and flight-test measurements on a single-main-rotor helicopter indicate that the damping moment about the helicopter center of gravity produced during pitching or rolling by a rotor which has flapping hinges on the rotor shaft, which depends primarily on four quantities: rotor speed, blade mass factor, height of the rotor hub above the helicopter center of gravity, and the ratio of collective pitch to the thrust coefficient - solidity ratio.

Report presenting three experimental investigation conducted with 75-millimeter-bore cylindrical roller bearings to determine the effects of roller axial clearance ratio, cage diametral clearance ratio, and cage land width-diameter ratio on bearing operating temperatures, wear, cage slip, and high-speed operating characteristics.

Report presenting an investigation to determine the performance of large tailless and conventional airplanes. The primary conclusion drawn fro the testing is that large all-wing tailless airplanes may have better performance characteristics than their equivalent tail-boom airplanes for certain types of missions. Results regarding a general performance comparison, performance variations with structural weight, landing speed, and take-off distance, and performance comparison based on arbitrary design specification are provided.

Note presenting a description of an adiabatic specific-heat calorimeter bridging the interval between 4 and 15 degrees Kelvin temperatures. The instrument uses a constant-volume helium gas thermometer as the working thermometer. The instrument is tested on an alloy and a sample of pure titanium and the results are described.

Report presenting the effects of approximately 50-percent biaxial stretch-forming on the tensile and crazing properties of polymethyl methacrylate. Results indicated that biaxially stretch-forming polymethyl methacrylate approximately 50 percent does not affect its tensile strength of secant modulus of elasticity in tension. Results regarding standard tensile tests, stress-solvent crazing tests, long-time tensile tests, discussion of mechanism of crazing, accelerated weathering tests, additional experimental work, and possible applications of stretch-forming are provided.

From Summary: "The difficulties experienced in properly holding thin tipped or tapered airfoils while testing on an N.P.L. type aerodynamic balance even at low air speeds, and the impossibility of holding even solid metal models at the high speeds attainable at the National Advisory Committee's wind tunnel, necessitated the design of a balance which would hold model airfoils of any thickness and at speeds up to 150 m.p.h. In addition to mechanical strength and rigidity, it was highly desirable that the balance readings should require a minimum amount of correction and mathematical manipulation in order to obtain the lift and drag coefficients and the center of pressure. The balance described herein is similar to one in use at the University of Gottingen, the main difference lying in the addition of a device for reading the center of pressure directly, without the necessity of any correction whatsoever. Details of the design and operation of the device are given."

"The investigation described in this report is concerned with the changes in the aerodynamic characteristics of an airfoil which are produced by a gauze-covered suction slot, located near the leading edge, and connected by an air passage to a split flap at the trailing edge. The tests were conducted at the Langley Memorial Aeronautical Laboratory. At the larger values of lift coefficient where the action of the slot might be expected to be most effective, the pressure differences were such that the air flowed out of the slot rather than in through it, and in consequence, the maximum lift coefficient was decreased" (p. 1).

Note presenting temperatures of a turbosupercharger rotor measured in flight for a variety of conditions by thermocouples, the leads of which were brought away from the turbine by means of rotating slip rings and stationary brushes. A consistent and almost linear relation was shown between turbine temperature at the outer edge of the rim and the effective exhaust-gas temperature at the surfaces of the blades on three successive flights at cruising power.

Report presenting a number of tests on the effect of service stresses on impact resistance, X-ray diffraction patterns, and the microstructure of the 25S aluminum alloy.

Note presenting an analysis of a step landing of a seaplane on smooth water by solving Newton's differential equation of motion. Formulas are developed for the maximum acceleration, the maximum draft, and the draft at the instant of maximum acceleration.

Note presenting an accurate method of determining secondary stresses in thin-walled, uniform beams of closed cross section. In the first part of the report, the integrodifferential equation governing axial displacements is formulated and solved for a beam without longitudinal stiffeners. In the second part, the corresponding summation-difference equation is developed and solved for a beam with stiffeners.

Results are presented of a wind-tunnel investigation made to determine the influence of the fuselage and tail surfaces on the rotary derivatives in yawing flight of a transonic-airplane configuration having 45 degrees sweptback wing and tail surfaces. The tests were run in the curved-flow test section of the Langley stability tunnel at a Reynolds number of 1.07 X 10 to the sixth power and consisted of balance measurements throughout the angle-of-attack range for several flight-path radii of curvature. The results are compared with data from forced-oscillation and free-oscillation tests, and a description of testing techniques used is included.

Report presenting an investigation to develop screech instrumentation and to study the mechanism of screech in a 6-inch-diameter simulated afterburner. Probe microphones have been developed to measure frequency, relative amplitude, and relative phasing of the pressure oscillations at positions in a screeching combustor.

The interaction of bearing and tensile loads on the creep behavior of joints was studied. A specimen was designed for this study which possessed some of the general features of pin and rivet joint connections and an apparatus was constructed to apply both bearing and tensile loads to the joint model. Deformation measurements were made by use of a photogrid printed on the joint model.

Report presenting a critical comparison and summary of the various methods proposed for calculating the unit thermal conductance on the outer surface of a heated wing involving both laminar and turbulent boundary layers, and a new equation is suggested that should indicate the effect of pressure gradient on laminar heat transfer.

Report presenting heat-transfer and pressure-drop data for a system in which air flows over a heated flat plate containing strips of metal. The strips are referred to as "boundary-layer interrupters" or "turbulence promoters". Results regarding heat transfer as a function of power consumption are also provided.

Report presenting an investigation of the diameter of vaneless diffusers and how it affects the variations in compressor and diffuser efficiency. The primary efficiency losses occurred in the vicinity of the diffuser entrance and exit. The effect of diffuser diameter was very slight on nearly all characteristics studied.

A low-turbulence investigation was made of an aerodynamically smooth NACA airfoil with faired surfaces back to 37 percent chord to determine the magnitude of boundary-layer Reynolds number at various points of transition in flow along different airfoil surfaces. Values of the section drag coefficient were also obtained by means of the wake-survey method.

Note presenting the development of iteration equations for a simplified solution of the nonlinear compressible-flow equation and its application to two profiles, the ellipse and the Kaplan section. Limitations imposed on the solutions by simplifications in the differential equation and the boundary conditions are discussed.

A study has been made of the important principles involved in the operation of a baffle for an engine cylinder and shows that cooling can be improved by 20 percent by using a correctly designed baffle. Such a gain is as effective as a 65 percent increase in pressure drop across the standard baffle, which had a 1/4 inch clearance between baffle and fin tips.