"On the basis of a recently developed theory for finite sweptback wings at supersonic speeds, calculations of the supersonic wave drag at zero lift were made for a series of wings having thin symmetrical biconvex sections with untapered plan forms and various angles of sweepback and aspect ratios. The results are presented in a unified form so that a single chart permits the direct determination of the wave drag for this family of airfoils for an extensive range of aspect ratio and sweepback angle for stream Mach numbers up to a value corresponding to that at which the Mach line coincides with the wing leading edge. The calculations showed that in general the wave-drag coefficient decreased with increasing sweepback" (p. 1).

"An investigation was conducted to compare the knock-limited performance of a 20-percent triptane blend in 28-K fuel with that of 28-R and 33-R fuels at high engine speeds, cruising speeds, and two compression ratios in an K-1830-94 multicylinder engine. Data were obtained with the standard compression ratio of 6.7 and with a compression ratio of 3.0. The three fuels were investigated at engine speeds of 1800, 2250, 2600, and 2800 rpm at high and low blower ratios" (p. 1).

Report presenting testing of a series of thin, triangular plan-form wings, including eight triangular wings of vertex angles and three swept-back wings with circular-arc sections. Results regarding lift, center of pressure, and ideal operation of different types of wings are provided.

Report presenting part of the results obtained to determine the effects of compressibility at high Mach numbers on a model of the Bell XS-1 transonic research airplane. General trends that can be qualitatively analyzed for level-flight Mach numbers up to 0.93 are given. Results regarding force characteristics and a comparison of results with wing-flow investigation are also provided.

"The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of a scout-bomber airplane. Comparisons are made between the root bending-moment and section torsional-moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending-moment coefficients but considerable disagreement for the torsional-moment coefficients" (p. 1).

Effect of inlet-air pressure and temperature on the performance of the X24-2 10-Stage Axial-Flow Compressor from the X24C-2 turbojet engine was evaluated. Speeds of 80, 89, and 100 percent of equivalent design speed with inlet-air pressures of 6 and 12 inches of mercury absolute and inlet-air temperaures of approximately 538 degrees, 459 degrees,and 419 degrees R ( 79 degrees, 0 degrees, and minus 40 degrees F). Results were compared with prior investigations.

"For about the past year, American Airlines has been engaged in obtaining data on various uses of airborne radar under routine operating conditions. This work is under contract to the Navy Department, Bureau of Ships, and includes the investigation of radar as a navigational aid and terrain collision warning device and its use in icing and turbulence detection. In view of the work of the National Advisory Committee for Aeronautics on atmospheric turbulence, the NACA was requested to participate in the tests to the extent of obtaining and evaluating the turbulence data for use in the turbulence-detection phase of the work" (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 June 11, 1947 to July 11, 1947 are presented.

Report presenting tests at Mach numbers between 1.36 and 2.01 of a twin-scoop air intake enclosing 61.5 percent of the maximum circumference of a body of revolution and located five forebody diameters behind the apex, which showed that the total pressure recovered after diffusion was about 10 percent greater than that attained in previous tests with an annular entrance of the same area.

Report presenting the results of tests on a model of a jet-propelled airplane and a comparison of drag, maximum lift coefficient, and elevator angle required for level flight in the wind tunnel and in flight. Results regarding the aerodynamic characteristics, longitudinal control, wing pressure distribution, and dive-recovery flaps are provided.

Report presenting testing on parabolic bodies of revolution of two fineness ratios in the transonic and supersonic range. One had a body fineness ratio of 7.87 and one had a ratio of 12 and were tested under different Mach number ranges. Experimental results and drag estimates of various portions of the body are provided.

Report presenting an investigation of a one-eighth segment of an annular combustor suitable for use as a component of an experimental turbojet engine. Due to the small space available for the combustor, a special design involving a minimum of obstructions in the combustion chamber was created. Results regarding the temperature-rise efficiency, total-pressure loss, and exhaust-gas temperature variation for several simulated engine operating conditions are provided.

Memorandum presenting a review of information relating to aircraft fires to determine what new or further research might lead to a substantial reduction of the aircraft fire hazard in flight and following crashes. An examination of fuels, lubricants, and hydraulic fluids as inflammable liquids is presented, together with possible sources of ignition under the general categories of hot surfaces, electric sparks and arcs, flames, and hot gases.

Memorandum presenting equations for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and applying the nozzle-design method of the report.

Report presenting testing of seven models that from two different wing series: a series of taper ratio 0.5 and differing aspect ratio and a series of aspect ratio 4 and differing taper ratio. Measurements of lift, drag, and pitching moment were made at Mach number 1.53. The aerodynamic parameters generally varied with aspect ratio and taper ratio in the manner indicated by the linear theory.

"A bibliography of NACA papers on rotating-wing aircraft issued up to July 1948 is presented. The list of papers is subdivided for ready reference under appropriate subject headings, and the titles are listed chronologically within each subject" (p. 1).

Wind-tunnel tests of a simplified nacelle on a semispan wing having approximately 35 degrees of sweepback were made at low speeds to evaluate the effects of the nacelle on the aerodynamic characteristics of the wing. Force, moment, and pressure-distribution measurements are presented for the nacelle underslung and centrally mounted on the wing and mounted on a strut below the wing.

"An investigation of the rolling effectiveness at transonic and supersonic speeds of a wing-aileron configuration simulating the D-558-2 airplane has been made by means of a rocket-propelled test vehicle. The variation of rolling effectiveness with Mach number is similar to that obtained previously for tapered sweptback wings having full-span, 0.2-chord ailerons" (p. 1).

Report presenting a wind-tunnel investigation at low speed to determine the aerodynamic characteristics of a 51.3 degree sweptback semispan wing with a raked tip and with 16.7-percent-chord sealed plain ailerons. Lift, drag, pitching-moment, and hinge-moment data were obtained for the wing with transition free and fixed with various spans of aileron deflected as lift flaps. The rolling moment, yawing moment, hinge moment, and aileron seal pressure characteristics were determined for each of the nine possible aileron-span and trailing-edge-angle combinations tested.

Report presenting static-pressure measurements made through the speed of sound by the NACA wing-flow method at the back of two unswept circular cylinders and one sweptback cylinder. Static pressures were found to decrease considerably with an increase in Mach number. Information about the length and diameter of the cylinders and how it affects measurements is provided.

Report presenting results of an experimental investigation to determine the temperature distribution in an aircraft-engine gas-turbine disk. Calculated stresses based on the measured temperature distributions are presented. Results regarding stresses in the inner region of the disk and stresses in the rim of the disk are provided.

Report presenting a semispan triangular wing with a constant-chord trailing-edge flap to evaluate the aerodynamic characteristics of the wing with landing speeds up to a Mach number of 0.95. Tests were included to ascertain the effects of the addition of a body and of modifications to the airfoil section. Results regarding the wing alone with low Mach number, wing alone with high Mach number, effect of the body, effect of the flap, effect of Mach number, lift-drag ratio, and wing-profile modifications are provided.

Results of wind-tunnel tests of a semispan model of a triangular wing of aspect ratio 2 with a skewed wing-tip flap are presented. Lift, drag, pitching-moment, and hinge-moment data are included for subsonic Mach numbers up to 0.95. The flap showed extremely high hinge moments and low effectiveness as a longitudinal control. Although less affected by compressibility, this flap is indicated to be inferior to a constant-chord flap when applied to this triangular wing.

Report discussing the hydrodynamic characteristics of a flying boat with a low-drag, planing-tail hull compared with a conventional-type hull. The planing-tail model had more take-off stability than the conventional model and had lower hydrodynamic resistance. Information about the landing stability, variation of trim with speed, and spray characteristics is also provided.