Report presenting a study of the factors influencing the performance of aerodynamic brakes. The increases in drag coefficient that are characteristics of several types of wing and fuselage aerodynamic brakes, which have been tested in wind tunnels or in flight, are summarized in the report.

Report presenting an experimental investigation to determine the orifice coefficient of a jet direct perpendicularly to an air stream as a function of pressure ratio and jet Reynolds number for circular, square, and elliptical orifices. The effect of air-stream velocity on the jet flow was also determined for three tunnel-air velocities.

Report presenting an investigation of a turbine and propeller to determine the conditions of maximum-efficiency operation when utilized as an independent turbine-propeller combination. The procedure used to determine the conditions of maximum efficiency and speed ratio between the turbine and propeller is described.

From Introduction: "The flare assumed is based primarily on reference 1, in which information permitting calculation of the flare characteristics of an airplane was obtained from flight tests. The results of calculations for airplanes having constant lift-drag ratio during the flare are plotted in chart form."

Note presenting an experimental investigation conducted to determine the orifice coefficient of a jet directed perpendicularly to an air stream as a function of pressure ratio and jet Reynolds number for circular, square, and elliptical orifices. The effect of air-stream velocity on the jet flow was also determined for three tunnel-air velocities. Results regarding jets discharging into still air and effect of tunnel-air velocity on jet flow.

Report presenting the hydrodynamic characteristics of a swept planing-tail hull as determined by water tank testing. The hull shape was based on results from previous testing indicating that symmetrical airfoil sections and slender boom-like afterbodies lower the drag. Results regarding spray characteristics, take-off stability and trims, landing stability, resistance, and directional stability are presented.

Memorandum describing preliminary investigations of two 3-inch-diameter slotted test sections over a range of pressure ratios from 1.3 to 10.0. The two test sections varied based on the number of slots and amount of open space, but they showed no appreciable difference in performance. Results regarding the slots with no chamber around the test section and with a closed chamber around the test section are provided.

Report presenting an investigation in the high-speed 7- by 10-foot tunnel to determine the high-subsonic aerodynamic characteristics of three different types of flying-boat hull: a planing-tail hull, a blended hull, and an airfoil-forebody swept hull.

Memorandum presenting flight tests with a fighter airplane to study the effect of boundary-layer suction aft of the shock wave on airfoil drag at supercritical Mach numbers and high Reynolds numbers. Airfoil chord force was determined from pressure-distribution measurements obtained at a range of Mach numbers at steady dives. Results of the tests showed no measurable effect of suction for the suction coefficient available.

Report presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of a 45 degree sweptback horizontal-tail model of aspect ratio 2 and a comparison of these results with results for a model of the same aspect ratio with an unswept hinge line. Results regarding the lift and hinge-moment parameters, static longitudinal stability, effect of Reynolds number, effect of standard roughness, effect of removing elevator nose seal, and visualization of the air flow are provided.

From Introduction: "This paper presents the results of the investigation of the wing-alone and wing-fuelage configurations employing a wing with the quarter-chord line swept back 60^o, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section parallel to the free stream."

Report presenting an altitude-chamber investigation to determine the altitude performance characteristics of the British Rolls-Royce Nene II turbojet engine with a standard 18.75-inch-diameter jet nozzle. Results regarding the simulated flight performance and generalized performance across other altitude and pressure characteristics are provided.

Report presenting surveys of the flow of the asymmetric adjustable nozzle of the 6- by 6-foot supersonic wind tunnel, which were made to determine the uniformity of the air stream. Test techniques for minimizing the effects of stream irregularities and the results of force and pressure-distribution tests of a swept-wing model are presented to illustrate the effectiveness of these techniques.

Report discussing an investigation of the aerodynamic characteristics of an airfoil-forebody swept flying boat hull with a wing and tail swept back 51.3 degrees at the leading edge. The swept hull's minimum drag coefficient was about the same as the parent model or streamline model. Various combinations of flaps were also utilized.

Report presenting a low-speed wind-tunnel investigation to determine the lateral control characteristics of extensible wing-tip ailerons on an untapered semispan wing with two configurations; one was unswept and had an aspect ratio of 3.13 and the other was swept back 45 degrees and had an aspect ratio of 1.59. Results regarding the plain-wing aerodynamic characteristics and lateral control characteristics are provided.

Memorandum presenting an investigation conducted to evaluate the effectiveness of a simple internal regenerative fuel preheater for a 20-inch-diameter ram jet. Data obtained at subsonic sea-level conditions indicated that fuel could be successfully preheated in this manner.

Report presenting free-flight investigations conducted on four 16-inch-diameter ramjet units to determine the performance at high subsonic and supersonic velocities. Data for evaluating the performance were obtained from radio-telemetering and radar-tracking equipment. Results regarding combustion performance, diffuser total-pressure recovery, thrust coefficient, and external drag coefficient are provided.

Report presenting an analysis of the effects of compressibility on the pressure coefficients of several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of linearized equations of compressible flow. The results indicated that the theoretical methods predict the subsonic pressure-coefficient changes over the central portion of the body but do not predict the pressure-coefficient changes near the nose.

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.

Report presenting a supersonic compressor design with supersonic velocity at the entrance of the stator on the assumption of two-dimensional flow. The rotor and stator losses assumed in the analysis are based on the results of preliminary supersonic cascade tests. The starting conditions and stability of the flow in rotor and stator are discussed, and the desirability of the variable-geometry stators and adjustable guide vanes is indicated.

"Four 90 degree two-dimensional turning passages designed by the method of characteristics were tested at an inlet Mach number of 1.71. The measured losses varied from 5 to 15 percent of the inlet stagnation pressure. The smallest loss was obtained for a passage in which separation on the convex surface was minimized through the introduction of a favorable pressure gradient" (p. 1).

Investigation conducted in the altitude wind tunnel to study the effect of Reynolds number on the performance of an axial-flow compressor. The compressor was operated as a part of a turbojet engine over a range of pressure altitudes and compressor-inlet Reynolds numbers. Results regarding compressor efficiency, air flow, and a comparison with axial-flow compressors of different design are provided.

Memorandum presenting a method for computing the isentropic and actual enthalpy change between the inlet and outlet of a centrifugal-flow compressor when water injection is used. The method of calculation is based on fluid property values given in steam and air tables.

Report presenting wind-tunnel tests that have been conducted to evaluate the independent effects of Reynolds and Mach numbers on the aerodynamic characteristics of a horizontal tail of aspect ratio 4.5 with a plain sealed elevator with a tab. Lift, drag, pitching moment, elevator hinge moment, tab hinge moment, streamwise distribution of static pressure at the midsemispan, and pressure difference across the elevator-nose seal were measured.