Note presenting tables and figures of a standard atmosphere based on the Manual of the ICAO Standard Atmosphere. Detailed tables of pressures and densities are given for altitudes up to 20,000 meters and to 65,000 feet.

Report presenting a description of a pyrometer that is self-balancing and is able to replace the two conventional manual operations of the line-reversal method. A description of the operation of the pyrometer and the performance and results are provided.

Report presenting handling-quality flight tests using an SB2C-5 drone under radio remote control from an F6F-5 control plane. Similar tests were conducted with the drone under manual control. The beep-type, remote-control system investigated was generally satisfactory for flight testing an airplane via remote control, including take-off and landings.

Note presenting an instrument that measures small absolute humidity changes by photoelectric examination of the 9440 angstrom units absorption band of water vapor. The instrument consists of a small source of light which sends its radiation over an air path of less than 1.5 meters to a dispersing system.

Note presenting the design of an instrument utilizing Wheatstone bridge type of pressure sensing units that is capable of integration of airfoil pressures into a quantity representative of the normal force and pitching moment acting on the airfoil. Flight and wind-tunnel versions of the instrument are briefly described along with samples of test data obtained from them.

"The arrangement of the parts and the installation and control problems of the two-stage mechanically driven superchargers for aircraft engines are discussed. Unless an entirely new form of supercharging is developed, there will be a definite need for a two-stage centrifugal supercharger. It is shown that the two-stage mechanically driven supercharger itself is a comparatively simple device; the complications arise from the addition of inter-coolers and controls" (p. 1).

Report presenting an investigation regarding the strengths of bonds between different chemical types of adhesives and adherends. Some of the topics explored include the theoretical aspects of adhesion and properties of adhesively bonded structures.

Discussed here are results already achieved with sonic altimeters in light of the theoretical possibilities of such instruments. From the information gained in this investigation, a procedure is outlined to determine whether or not a further development program is justified by the value of the sonic altimeter as an aircraft instrument. The information available in the literature is reviewed and condensed into a summary of sonic altimeter developments. Various methods of receiving the echo and timing the interval between the signal and the echo are considered. A theoretical discussion is given of sonic altimeter errors due to uncertainties in timing, variations in sound velocity, aircraft speed, location of the sending and receiving units, and inclinations of the flight path with respect to the ground surface. Plots are included which summarize the results in each case. An analysis is given of the effect of an inclined flight path on the frequency of the echo. A brief study of the acoustical phases of the sonic altimeter problem is carried through. The results of this analysis are used to predict approximately the maximum operating altitudes of a reasonably designed sonic altimeter under very good and very bad conditions. A final comparison is made …

This note investigates the effect of high altitude or low atmospheric pressure upon the operation of an engine and the effect of the low pressure and lack of oxygen and of the very low temperatures upon the pilot and upon the performance of the airplane itself.

Several improvements that have been made on commercially available carbon-monoxide indicators to make them more suitable for aircraft use are described. These improvements include an automatic flow regulator, which permits the use of a simplified instrument on aircraft where a source of suction is available, and a more reliable alarm attachment. A field method for testing instruments on standard samples of carbon monoxide is described. Performance data and instructions in operation and maintenance are given.

Report presenting a survey of the technical information contained in the literature on the subject of lubrication, friction, and wear of aircraft engine piston rings.

"The employment of steam power plants in aircraft has been frequently proposed. Arguments pro and con have appeared in many journals. It is the purpose of this paper to make a brief analysis of the proposal from the broad general viewpoint of aircraft power plants. Any such analysis may be general or detailed" (p. 1).

Note presenting a determination of the accuracy with which pressure altitude can be measured by calculation of the errors in the measuring system, errors arising from operation of the system, and variations in atmospheric pressure. Some possibilities for reducing errors in the categories of altimeter-scale error, static-pressure error, atmospheric-reference error, flight technical error, friction error, and service error are provided.

The gyroscopic instruments commonly used in instrument flying in the United States are the turn indicator, the directional gyro, the gyromagnetic compass, the gyroscopic horizon, and the automatic pilot. These instruments are described. Performance data and the method of testing in the laboratory are given for the turn indicator, the directional gyro, and the gyroscopic horizon. Apparatus for driving the instruments is discussed.

A discontinuous variation of coefficients of the differential equation describing the linear control system before nonlinear elements are added is studied in detail. The nonlinear feedback is applied to a second-order system. Simulation techniques are used to study performance of the nonlinear control system and to compare it with the linear system for a wide variety of inputs. A detailed quantitative study of the influence of relay delays and of a transport delay is presented.

Note presenting a summary of all phases of an investigation of fretting corrosion that has been conducted over a period of several years. Part I describes a test machine for measuring fretting damage under controlled experimental conditions. Part II presents data for mild steel fretted against itself, with a number of characteristics taken into consideration. Part III suggest a mechanism for the fretting process.

A series of papers describing a system that will automatically record as many as 300 pressures, 200 voltages, and 24 frequencies in as little as 30 seconds to an accuracy of 0.15 percent or better of full-scale range. The information is able to be used in any high-speed, general-purpose digital computer. The computer will accept the encoded data produced by the recording system and automatically calibrates it, takes averages, forms ratios, and does terminal calculations such as mass flow, momentum, distortion numbers, drag coefficients, thrust, specific fuel consumption, and efficiency.

Note presenting a machine which will automatically measure and record 100 pressures in a range from 5 to 65 inches of mercury, in approximately 2.5 minutes, to an accuracy of 0.1 inch of mercury. The method used is to compare the unknown pressures with a scanning pressure whose value at any instant is known in digitalized form.

"An investigation of three methods for the prevention and the removal of ice on an airplane windshield has been completed. The methods were: electric heating; hot-air heating; and an alcohol-dispensing, rotating wiper blade. The results showed that vision through the airplane windshield could be maintained during severe icing conditions by the use of heat" (p. 1).

Note presenting an experimental program to study the subject of metal fatigue and to determine and evaluate the fundamental factors which influence the behavior. The statistics of the fatigue-fracture curves and endurance limits were determined for a variety of metals and the effects of some metallurgical factors on the statistical nature of fatigue properties were shown.

Note presenting a method for strength analysis of stiffened shear webs, which has been revised and extended from a previous report. A set of formulas and graphs which cover all aspects of strength analysis is given, experimental data are presented, and the accuracy of the formulas as judged by comparison with the data is discussed.

Note presenting a theoretical study of the motions experienced by aircraft in response to sharp-edge, harmonic, and random gusts. These are compared with approximate solutions based on commonly used assumptions, and the validity of each of the assumptions is assessed.

Report presenting an investigation of the flutter characteristics of a uniform, unswept, cantilever wing of high aspect ratio and under conditions of high mass coupling by means of a Rayleigh type analysis based on coupled modal functions. Results are compared with an experiment and the calculated results of NACA TN 1902.

Report presenting a method for the rapid prediction of the shape of attached shocks emanating from smoothly contoured axisymmetric and two-dimensional nose shapes. From a practical viewpoint, the accuracy of the method is comparable to that of the method of characteristics.