From Summary: "These properties compare favorably with those of the strongest similar alloys previously investigated. However, compared with a 60Cr-25Fe-15Mo alloy, the three cobalt-chronium-nickel cast alloys are inferior. A correlation of NACA and OSRD (Project NRC-8) data is presented, showing the variation of rupture strengths with temperature in the range of 1350^o to 2000^o for alloys."

Report discussing an experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.

From Introduction: "The surging of a system containing a centrifugal- or axial-flow compressor (e.g., refs. 1 to 4) is an example of self-sustained oscillation. Inlets designed for supersonic jet engines also have been observed to induce oscillations (e.g., refs. 5 to 11) which are usually referred to as "buzz." The origin of buzz in ram-jet engines is the subject of the present report."

Report discussing both laboratory and weather-exposure corrosion tests showed conclusively that the protection afforded by aluminum pigmented spar varnish coatings applied to previously anodized aluminum surfaces was greatly superior to that afforded by the same coatings applied to surfaces which had simply been cleaned free from grease and not anodized.

Report discussing a flight investigation of rocket-powered models of a tailless triangular-wing airplane configuration was made through the transonic and low supersonic speed range at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. An analysis of the aerodynamic coefficients, stability derivatives, and flying qualities based on the results obtained from the successful flight tests of three models is presented.

Note presenting an investigation to determine the effects of airspeed and angle of attack on the lift, drag, and pitching moment of a shrouded-propeller model with a shroud length of about two-thirds the propeller diameter over an angle of attack from 0 to 90 degrees. Tests were made of the complete model with the propeller operating and also of the shroud and motor combination with the propeller removed.

From Summary: "This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values."

From Introduction: "The present paper employs an approach believed to be novel in slender-body theory and is concerned with developing formulas for the forces and moments as well as the stability derivatives for slender wing-body combinations."

From Introduction: "The present paper employs an approach believed to be novel in slender-body theory and is concerned with developing formulas for the forces and moments as well as the stability derivatives for general slender wing-body combinations."

From Introduction: "The present report gives the results of tests made on a tapered wing with a nontapered auxiliary airfoil affixed to it. The wing was the one used in reference 7."

"For the calculation of the parasite resistance of an airplane, a knowledge of the resistance of the individual structural and accessory parts is necessary. The most reliable basis for this is given by tests with actual airplane parts at airspeeds which occur in practice. The data given here relate to the landing gear of a Siemanms-Schuckert DI airplane; the landing gear of a 'Luftfahrzeug-Gesellschaft' airplane (type Roland Dlla); landing gear of a 'Flugzeugbau Friedrichshafen' G airplane; a machine gun, and the exhaust manifold of a 269 HP engine" (p. 1).

"The design and construction of an altitude chamber, in which both pressure and temperature can be varied independently, was carried out by the NACA at the Langley Memorial Aeronautical Laboratory for the purpose of studying the effects of temperature and pressure on aeronautical research instruments. Temperatures from +20c to -50c are obtained by the expansion of CO2from standard containers. The chamber can be used for the calibration of research instruments under altitude conditions simulating those up to 45,000 feet" (p. 1).

From Introduction: "The object of the present paper is to present an approximate method for calculating accurately the thermal stresses in a thin plate with both chordwise and spanwise variations in temperature and chordwise but restricted spanwise variations in thickness."

Note presenting normal-acceleration and airspeed data obtained for one type of twin-engine transport airplane in commercial operations in order to determine the gust and gust-load experiences of the airplane. Results regarding acceleration experience, gust experience, seasonal effects, and effect of special operating restriction are provided.

From Introduction: "The data for operations both with and without radar installed have been analyzed and the results are presented in this paper. Although these results are of limited extent, they provide a basis for early examination of any trends in the gust loads and associated operating practices which might be attributed to the use of radar."

From Introduction: "Results obtained in the experimental investigations of secondary flows in turbomachines (refs. 1 to 3) indicate that information concerning three-dimensional laminar boundary-layer behavior can be of practical value in interpreting and correlating measurements of losses in the turbo-machines for design purposes. Reference 4 gives a theoretical analysis of the overturning (more than mainstream turning) of the three-dimensional laminar boundary layer developed on flat or nearly flat surfaces, under mainstream flows which consist of streamline translates (i.e., the entire streamline pattern can be obtained by translating any particular streamline pattern can be obtained by translating any particular streamline parallel to the leading edge, fig. 1) with constant axial velocity component."

From Introduction: "This paper summarizes the results of an analysis of V-G records taken on Douglas DC-2 airplanes during the period from June 1935 to December 1940. The operational life is compared with the operational lives of other airplanes flown on different routes during the corresponding period."

From Introduction: "It is shown in the body of this report that the solution to the error problem depends upon a more or less arbitrary definition, the only criterion as to the choice of the definition being the usefulness of the solution to which it leads. In this respect, it may be said of the method derived herein that it is not difficult to apply and appears to lead reasonable values of the errors."

"The purpose of this paper is to provide a derivation of the general integral form of the boundary equation without neglecting the Reynolds normal-stress term. Two special cases of this equation are given explicitly" (p. 2).

From Summary: "Included in the report are the results of total-pressure surveys made at downstream ends of the mixing tubes."

Note presenting the general equations governing the fixed-trim water landing of a straight-keel seaplane with a hull of arbitrary constant cross section in such a form that the landing motions and loads are expressed in terms of the steady planing characteristics of the seaplane.

Note presenting concepts involved in the harmonic-response-function method, such as the direct or conjugate characteristic modes, by application of the method to the calculation of the change in flutter characteristics of a wing due to adding concentrated masses.

Note presenting a description of the use of silver chloride as a material for photoelastic stress analysis, which offers the possibilities of studying both elastic and plastic states of stress in a crystalline metallike material on either a microscale or macroscale. In order to use it, however, it is necessary to relate the stress state quantitatively with the observed relative retardation and extinction angle.

Note presenting a modification of certain variational methods for the approximate solution of subsonic and transonic flows to compensate for the fact that those methods fail as soon as shock waves occur. By applying a variational principle to the regions of flow behind shock waves and Bateman's original principle to the other regions in the fluid, shock equations can be directly obtained.