Memorandum presenting wind-tunnel tests to determine the aerodynamic characteristics of a 15-percent- and a 35-percent-chord plain trailing-edge flap on the NACA 0006 airfoil section. Simultaneous measurements of section lift, drag, and pitching moment were made over a range of Mach numbers, angles of attack, and flap deflections.

Report presenting the drag of a series of complete airplane-like configurations and their components at transonic velocities using the free-fall method. The configuration tested in this report has a 45 degree sweptback wing of aspect ratio 4.1 mounted forward of the maximum diameter of a 10-inch-diameter body of fineness ratio 12 equipped with stabilizing tail fins. Results are presented as curves showing the variation of drag coefficient with Mach number for the complete configuration and for each component.

Report presenting an investigation using a 4600 pound-thrust turbojet engine as part of a program to determine the comparative performance of fuels conforming to specifications AN-F-58 and AN-F-32. Results regarding the altitude performance, altitude low-speed blow-out limits, idling limits of fuel-metering control, altitude windmilling starts, carbon-deposition rates, and iron oxide contamination are provided.

Memorandum presenting an approximate method for the estimation of the properties of the incompressible laminar boundary layer on a flat plate in the slip-flow region using Karman's momentum method. At equivalent stations, the total thickness and the skin friction of a slipping boundary layer are less than that of the normal boundary layer at the same Reynolds number.

Report discussing testing using two rocket-propelled models to test the jettisonable-nose method of pilot escape. The nose was jettisoned successfully on the second attempt and the accelerations produced were found to be within human tolerance. The first test ended with a collision of the nose and wing, indicating that this is a possible risk during power-on flight.

Report presenting a wind tunnel investigation to determine the downwash angles, dynamic pressure loss, and wake width behind wings with sweep angles of 45, 30, and 0 degrees. Results indicated that the spanwise distribution of downwash was affected by sweep in a manner similar to span loading, increased toward the root by sweepforward and toward the tip by sweepback.

Tests were made in the Langley 7 by 10 foot tunnel on a model of a fighter-type airplane with external stores. The data obtained is presented and compared to flight-test results to determine the feasibility of estimating flight buffet Mach number from tunnel data.

Report presenting a survey of two-dimensional data on trim changes near maximum lift resulting from deflection of various types of leading-edge and trialing-edge high lift devices. Results regarding pitching-moment coefficients, pitching-moment increments, and maximum lift coefficients are provided.

An altitude-wind-tunnel investigation of the performance of AN-F-58 and AN-F-32 fuels in an experimental turbojet engine was conducted over a range of simulated altitudes and flight Mach numbers. Combustion efficiencies obtained with AN-F-58 and AN-F-32 fuels were approximately equal. The minimum-speed altitude operational limit was essentially the same with either AN-F-58 or AN-F-32 fuel. Starting characteristics of the two fuels were approximately the same at low wind milling speeds. Visual observation showed no apparent differences in the carbon-deposition rates of AN-F-58 and AN-F-32 fuels.

Report presenting testing of low-aspect-ratio triangular-plan-form lifting surfaces located on conical and cylindrical portions of a body have been determined at Mach number 1.2 and several subsonic speeds to determine if the aerodynamic characteristics of these surfaces at supersonic speeds could be improved by locating them in the subsonic conical-flow field. Results regarding lift and drag coefficients and lift-curve slopes are provided.

"An investigation has been conducted to determine whether three-dimensional flows may be utilized in axial-flow fan and compressor rotors so that the spanwise load distribution may be varied to obtain high pressure rise. Two rotors, one with approximately uniform and one with solid-body downstream tangential-velocity distributions, were designed and tested at the design blade angle" (p. 1).

"Results are presented of an investigation in the Langley 19-foot pressure tunnel of the longitudinal characteristics of a semispan model wing having 37 degrees sweepback of the leading edge, an aspect ratio of 6, and NACA 641-212 airfoil section perpendicular to the 27-percent-chord line. Several types of stall-control devices including extensible round-nose leading-edge flaps, a leading-edge slat, and a drooped leading edge were investigated; partial- and full-span trailing-edge split and double slotted flaps were also tested. In addition, various combinations of the aforementioned leading- and trailing-edge flaps were investigated" (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 13, 1947 to August 15, 1947 are presented.

From Summary: "Two rocket-powered models representative of a fighter-type airplane were investigated in flight at Mach numbers up to 1.01 and 1.07 by the Langley Pilotless Aircraft Research Division at its testing station at Wallops Island, Va. These models incorporated an inverse-taper wing and a vee tail and were flown with controls undeflected and wing and stabilizer set at 0 deg incidence. Values of lateral acceleration, normal acceleration velocity, and drag were obtained by use of telemeters and a Doppler velocimeter radar unit."

An investigation of the performance of several propellers on the YP-47M airplane at high blade loadings has been conducted in the Cleveland altitude wind tunnel at the request of the Air Materiel Command, Army Air Forces. As part of the program, a study was made of a Curtiss 836-14C2-18R1 four-blade propeller. The investigation was made for a range of power coefficients from 0.10 to 1.00 at free-stream Mach numbers of 0.30, 0.40, and 0.50 for density altitudes from 10,000 to 45,000 feet, engine powers from 150 to 2500 brake horsepower, and for engine speeds from 1000 to 2900 rpm.

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.

Design data are presented for the graphical construction of two-dimensional sharp-edge-throat supersonic nozzles of minimum length for test-section Mach numbers from 1.20 to 10.00. The method of characteristics used in the design is briefly reviewed.

A preliminary investigation of an axial-flow gas turbine-propeller engine was conducted. Performance data were obtained for engine speeds from 8000 to 13,000 rpm and altitudes from 5000 to 35,000 feet and compressor inlet ram pressure ratios from 1.00 to 1.17.

Performance properties and operational characteristics of an axial-flow gas turbine-propeller engine were determined. Data are presented for a range of simulated altitudes from 5,000 to 35,0000 feet, compressor inlet- ram pressure ratios from 1.00 to 1.17, and engine speeds from 8000 to 13,000 rpm.

The gust and draft velocities evaluated from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from May 13 to May 29, 1947 are presented.

"An investigation was conducted in an altitude test chamber to determine the effects of inlet airflow distortion on the compressor steady-state and surge characteristics of a high-pressure ratio, axial-flow turbojet engine. Circumferential-type inlet flow distortions were investigated, which covered a range of distortion sector angles from 20 deg to 168 deg and distortion levels up to 22 percent. The presence of inlet airflow distortions at the compressor face resulted in a substantial increase in the local pressure ratio in the distorted region, primarily for the inlet stages" (p. 1).

At the request of the Bureau of Aeronautics, Navy Department, investigations of the static-pressure losses and total-head distributions of the Westinghouse X24-C-2 inlet screen were made in the induction aerodynamics laboratory at Langley. The screen was investigated in two configurations, both before and after rounding the leading edges of the vanes. Investigations were conducted through air flows up to about pounds per second.

"An altitude-test-chamber investigation was conducted to determine the operational and performance characteristics of a McDonnell afterburner with a fixed-area exhaust nozzle on a J34 engine. At rated engine speed, the altitude limit, as determined by combustion blow-out, occurred as a band of unstable operation of about 6000-foot altitude in width with minimum altitude limits from 31,000 feet at a simulated flight Mach number of 0.40 to about 45,500 feet at a simulated flight Mach number of 1.00. Considerable difficulty was experienced in attempting to establish or maintain balanced-cycle engine operation at altitudes above 36,000 feet" (p. 1).

Wind-tunnel tests at low Mach number of a Republic F-84C airplane were conducted to determine by pressure-distribution measurements the air loads on wing-tip tanks and the change in wing load distribution due to the presence of tip tanks. Measurements of the aeroelastic twist of the wing were also obtained. Results are presented in the form of loading coefficient, center-of- pressure location, pitching-moment coefficient, aerodynamic-center location, and aeroelastic twist. The investigation revealed that the redistributions in loading brought about by either the tip tanks or elastic deformation of the wing were relatively small when compared with the chnnges in loading normally associated with the deflection of an aileron.