The following report discusses an investigation that was made to determine the tensile and the compressive properties of a large number of 24ST extruded shapes selected at random from commercial production in order to investigate the interrelation of these properties.

From Summary: "A theoretical analysis is presented that permits estimation of the changes in piston-temperature distribution induced by variations in the crown thickness, the ring-groove-pad thickness, and the undercrown surface heat-transfer coefficient. The analysis consists of the calculation of operating temperatures at various points in the piston body on the basis of the experimentally determined surface heat-transfer coefficients and boundary-region temperatures, as well as arbitrarily selected surface coefficients."

From Introduction: "The difficulties experienced in cooling the exhaust-valve seats of the rear-row cylinders have been overcome to a considerable extent by improving the mixture distribution through application of the injection impeller (reference 1) and by augmenting the flow of cooling air to the critical baffles (reference 2). Flight tests of this airplane (reference 3) indicated that the temperatures of exhaust-valve seats on rear-row cylinders were markedly lowered by these modifications and that airplane range, altitude, and gross weight previously limited by these temperatures could be greatly increased."

The following report covers an investigation that was done to supplement available experimental data on flow fields behind wings of an aircraft at supersonic speeds, as well as to furnish more quantitative information on the choice of the theoretical method for a given configuration and the accuracy to be expected when using such a method.

From the Introduction: "In the present reports the paths of liquid spray droplets issued in the flow field behind an airplane are calculated."

From Introduction: "This report presents only that portion of the data from the first ditching which was to be used roughly establish the accelerations experienced by the pilot and the amount of water pressure to which the fuselage structure was subjected during the ditching."

From Introduction: "The research program included clean-up tests (unpublished data) and stability and control tests (reference 1) made in the NACA Langley full-scale tunnel. An investigation of the aerodynamic characteristics of the power-plant installation in the Cleveland altitude wind tunnel is discussed in this report."

"The data presented in this report are part of a general program to determine the effects of xylidines on the knock-limited performance of currently used aviation fuels" (p. 2).

From Introduction: "The present report has been prepared to discuss the indications obtained from the University of Chicago turbulence indicator in relation to simultaneous measurement of atmospheric gustiness made by the NACA, which are summarized herein."

From Introduction: "An apparatus that gives a quick and an accurate measurement of the rate of discharge has been has been designed by the NACA and is described in this report."

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from September 4, 1947 to September 5, 1947 are presented.

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from June 11, 1947 to July 11, 1947 are presented.

From Introduction: "The heat-transfer data calculated from measured temperatures are compared with values calculated by the theory of Van Driest for a flat plate with laminar and turbulent boundary layers. In addition, the heat-transfer data from the flight tests are compared with data obtained from the Langley Structures Research Division of ground tests of an identical wing at a Mach number approximately equal to 1.99 in the pre-flight jet of the Langley Pilotless Aircraft Research Station at Wallops Island, Va. The stream static pressure is maintained at about 1 atmosphere, the free-stream temperature at about 75^o F, and the stagnation temperature at approximately 500 ^o F (ref.1)."

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from June 2, 1947 to June 7, 1947, are presented.

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from August 16, 1947 to August 20, 1947 are presented.

From Summary: "Data are included on the amount of fallout from the cloud and the concentration of boric oxide in the cloud."

The gust and draft velocities from records of NACA instruments installed in P-61c airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from July 12, to July 18, 1947 are presented.

"The results obtained from an evaluation for gust and draft velocities of acceleration and airspeed-altitude records taken by NACA recording instruments installed in P-61c airplanes participating in thunderstorm flights 6, 7, and 8 of July 9, 1946, July 10, 1946, and July 11, 1946, respectively, are presented herein. These data are summarized in tables I and II. In accordance with a recent discussion with a member of the U.S. Weather Bureau staff, the tabulated results for the present flight include in addition to data of the type presented in reference 1, the initial heading of the airplane for each traverse, the pressure altitude at the start of each traverse in increments of 500 feet, and the gust gradient distance when it could be evaluated" (p. 1).

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air FIeld, Ohio, from August 7, 1947 to August 13, 1947 are presented.

This report presents the results obtained from gust and draft velocity measurements within thunderstorms for the period August 7, 1946 to August, 13, 1946 at Orlando Florida. In several of the surveys, indications of ambient air temperature were obtained from photo-observer records. These data are summarized in the report.

From Introduction: "The design and flight evaluation of an airborne target simulator for use in tracking studies of fighter-type airplanes equipped with optical gunsights have recently been reported (ref. 1). In this equipment the target airplane was represented by a movable dot of light projected on the windshield of the test airplane."

Report presents the results of tests conducted at Stanford University of a 3-foot model propeller at four pitch settings and at 0 degree, 10 degrees, 20 degrees, and 30 degrees yaw.

This report is a revision of the altitude pressure tables of the United States standard atmosphere given in Technical Report No. 246 and the altitude range has been extended from 50,000 to 80,000 feet.

This report presents the results of an investigation undertaken to determine the feasibility of making glide landings in gusty air. Wind velocities were measured at several stations between the ground and a height of 51 feet, and flight tests were made to determine the actual influence of gusts on an airplane gliding close to the ground.