Note presenting flight investigations of single-axis attitude stabilization during low-speed instrument approaches. A single-rotor helicopter that had been modified to include an electronic control system was used in the investigation. Results regarding heading stabilization, pitch stabilization, and roll stabilization are provided.

Report presenting the results of experiments conducted to determine time constants of several bare-wire thermocouples mounted in cross flow to an air stream. Four pairs of common thermocouple materials with three different wire diameters were used. Results regarding the time constants, Nusselt numbers, effective gas temperature, and some numerical calculations are provided.

"The similarity rules for linearized compressible flow theory (Göthert's rule and its supersonic counterpart) are extended to second order. It is shown that any second-order subsonic flow can be related to "nearly incompressible" flow past the same body, which can be calculated by the Janzen-Rayleigh method" (p. 1).

Note presenting a method for analyzing extreme-value data which may arise in a wide variety of applications. Discussion of the method is preceded by the necessary statistical theory which also furnishes a basis for evaluating the new method in relation to existing ones. Several appendices are also included for mathematical developments not included in the text.

Note presenting some methods of estimating the induced drag of low-aspect-ratio wings, which are discussed and compared with experiments. The profile drag due to lift is also discussed and a method is developed which relates the effect of aspect ratio on the profile drag due to lift to an "effective" two-dimensional lift coefficient.

"The aerodynamic characteristics of indicially cambered two-dimensional airfoils in supersonic flow are determined theoretically. These indicial functions are used to determine the power required to sustain a general time-varying chordwise deformation. The harmonically oscillating parabolic mode is considered in detail and stability boundaries are presented for this case" (p. 1).

Report presenting a simple method for determining the nonlinear gains required to give optimum responses for step inputs of all magnitudes. The method is based on the fact that the control surface moves at its maximum rate during almost the entire transient maneuver and thus the servo system can be considered as a simple on-off type controller.

Note presenting the assumptions of the Prandtl-Busemann small-disturbance method, together with the requirements of continuity and irrotationality, which lead to a recursive system of first-order partial-differential equations. The results of the analysis are applied to the case of subsonic flow past a parabolic cylinder.

"Measurements were made of the resistance of fibrous-glass compacts to normal air flow. The flow resistance was related to the thickness and density. As a porous material for boundary-layer-control applications using area suction, the fibrous-glass compact could be made to any desired thickness and permeability and sandwiched between perforated rigid surfaces" (p. 1).

Note presenting theoretically derived charts showing the profile-drag-thrust ratio for a helicopter rotor operating in forward flight and with hinged rectangular blades with a linear twist of -8 degrees. The charts, which show the profile-drag characteristics of the rotor for various combinations of pitch angle, ratio of thrust coefficient to solidity, and a parameter representing shaft power input, are presented for tip-speed ratios ranging from 0.05 to 0.50.

Report presenting the low-speed yawed-rolling characteristics of two 40 x 12, 14-ply-rating, type VII aircraft under straight-yawed rolling over a range of inflation pressures and yaw angles for two vertical loadings. Static testing was performed to determine the vertical, lateral, torsional, and fore-and-aft elastic characteristics of tires. Measured lateral and torsional spring constants appeared to decrease with increasing amplitude of tire lateral distortion or twist.

Report presenting an experimental investigation to determine the effects of shroud-lip radius of curvature, shroud length, and shroud diffuser angle on the static thrust characteristics of a small-scale shrouded propeller which simulated a propeller submerged in the wing of an airplane. Results regarding the effect of propeller blade angle, effect of lip radius, effect of propeller location in shroud, effect of shroud length behind the propeller plane, effect of diffuser angle, and effect of ground proximity are provided.

From Introduction: "The results presented herein were calculated for a symmetrical diamond airfoil at zero angle of attack for a range of airfoil-thickness ratios from 0.02 to 0.10, pressure altitude from sea level to 45,000 feet, and free-stream static temperatures to -.40^o F."

From Introduction: "In order to provide engine-inlet matching to prevent such mass flow spillage and the attendant drags, much mechanical complication has been introduced. References 1 and 2 propose employing this principle at subsonic and supersonic speeds to achieve thrust augmentation. The merits of the system for supersonic engine-inlet airflow matching, as well as thrust augmentation, appear considerable; and a comparative study with existing fixed- and variable-geometry inlets was therefore undertaken."

Note presenting an examination of the applicability of some results from the theory of generalized harmonic analysis (or power-spectral analysis) to the analysis of gust loads on airplanes in continuous rough air. The general relations for linear systems between power spectrums of a random input disturbance and an output response are used to relate the spectrum of airplane load in rough air to the spectrum of atmospheric gust velocity.

"An analysis, based on the linearized thin-airfoil theory for supersonic speeds, of the wave drag at zero lift has been carried out for a simple two-body arrangement consisting of two wedgelike surfaces, each with a rhombic lateral cross section and emanating from a common apex. Such an arrangement could be used as two stores, either embedded within or mounted below a wing, or as auxiliary bodies wherein the upper halves could be used as stores and the lower halves for bomb or missile purposes. The complete range of supersonic Mach numbers has been considered and it was found that by orienting the axes of the bodies relative to each other a given volume may be redistributed in a manner which enables the wave drag to be reduced within the lower supersonic speed range (where the leading edge is substantially subsonic)" (p. 1).

Results are presented of an investigation of the effectiveness of a wing equipped with a 50-percent-chord sliding flap and a 30-percent-chord slotted flap in deflecting a propeller slipstream downward for vertical take-off. Tests were conducted at zero forward speed in a large room and included the effects of flap deflection, proximity to the ground, a leading-edge slat, and end plates. A turning angle of about 70 degrees and a resultant force of about 100 percent of the thrust were achieved near the ground. Out of the ground-effect region, the turning angle was also about 70 degrees but the resultant force was reduced to about 86 percent of the thrust.

A missile research model was flown at supersonic speed to determine the quality of automatic roll stabilization at varying angles of attack. Aerodynamic rolling and pitching derivatives were determined from the flight record. It was concluded that the combination of the gyro-actuated automatic pilot with wing-tip ailerons provided adequate roll stabilization under conditions encountered in flight.

Note presenting an investigation to determine the effect of propeller location and flap deflection on the lift, drag, and pitching-moment characteristics of a wing-propeller combination over a range of angles of attack. The model had four propellers, the slipstream from which covered practically the entire span of the wing. The results indicated that power factors exist for changing the variation of pitching moment with speed.

Report presenting a simplified analysis to estimate the extent to which the pressure ratio and power of a nonreturn supersonic wind tunnel operating in the low supersonic Mach number range can be reduced by the evaporation of water injected into the diffuser. It appears to be possible to reduce the power by as much as 20 percent for a typical example of a tunnel operating at Mach number 1.4.

Report presenting approximate solutions describing mainstream flows confined to regions of small angle variation over flat surfaces for three-dimensional, laminar, incompressible, thin boundary-layer flows with similar with respect to stationary polar coordinate systems. Results regarding the mainstream, boundary layer, ordinary differential equations, and comparison with experiment are provided.

Report presenting eleven 110-millimeter-bore ball thrust bearings made of M-1 tool steel were operated over a range of DN values at mean outer-race temperatures to 678 degrees Fahrenheit. Testing occurred at a variety of thrust loads, radial loads, oil flows, and oil inlet temperatures. Results regarding the difference between tests without heat addition and tests with heat addition, fatigue failures, performance of cage materials, and oil-interruption tests are provided.

Report presenting a discussion of the basic theory of pneumatic temperature probes and deviations from the basic theory in practical applications. Design requirements and operating conditions are discussed. Results regarding calibration tests and high-temperature tests and results are provided.

Note presenting the stress-rupture properties of commercially pure nickel at 1500 degrees Fahrenheit as determined for its application as a container material for molten sodium hydroxide. Stress-rupture tests of L-nickel tubes containing sodium hydroxide were run with atmospheres of air or argon external to the tubes. Sodium hydroxide was found to have little effect on the stress-rupture strength of nickel tubes tested in argon at 1500 degrees Fahrenheit for times up to 200 hours.