Report summarizing several experimental tail-pipe-burner investigations to indicate the effects of tail-pipe-burner design variables on the performance and operating characteristics. Most of the configurations were investigated over a wide range of altitudes and flight Mach numbers. The results indicate the desirable design features of a tail-pipe burner that will operate with high combustion efficiency and exhaust-gas temperature up to an altitude of approximately 50,000 feet.

A wind tunnel investigation was conducted to determine the performance of a 4000-pound-thrust axial-flow turbojet engine with a high flow compressor. Pressure altitudes included 5000 to 40000 feet with ram pressure ratios from 1.00 to 1.82. Altitudes included 20000 to 40000 feet and ram pressure ratios from 1.09 to 1.75. A comparison is made between engine performance with high flow and low flow compressors.

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.

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 10, 1947 to September 15, 1947, are presented.

Report presenting the flight-determined buffet boundaries of ten airplanes. Comparisons are made with five possible buffeting criteria related to airfoil-section characteristics. The primary factors that determine buffeting criteria are critical Mach number, Mach number of sonic flow at the crest, lift-divergence Mach number, lift-peak Mach number, and empirical buffeting criterion are provided.

From Summary: "The results of an experimental investigation of an NACA submerged-air-inlet system on a 1/5-scale model of a fighter airplane are presented. Preliminary development tests were conducted to select the optimum entrance configuration. Duct-system total-pressure losses and pressure distributions over the lip and ramp of this air intake were obtained."

The characteristics of a wedge static-pressure sensing element with various holder configurations were determined and compared with the characteristics of the conventional tube. The probes were tested over a range of Mach number from 0.3 to 0.95 and at various pitch and yaw angles. The investigation showed that the spike-mounted wedge sensing element has a pressure coefficient comparable with the conventional subsonic static-pressure probe and the pressure coefficient of the wedge varied less than that of the conventional probe for corresponding change of yaw angle.

From Introduction: "The purpose of the present paper is to investigate the effect of two-speed gearing on the take-off efficiency under certain conditions. The present paper gives charts from which the efficiencies can be readily computed for optimum rotational speeds. Also included is a brief discussion of the static thrust of thin propellers, including the effect of camber on the static thrust."

"Wind-tunnel tests were conducted to determine the longitudinal stability characteristics of a full-scale Northrop XSSM-A-3 missile. Various wing modifications were investigated in an effort to provide a configuration that would maintain longitudinal stability to lift coefficients necessary for landing the missile during flight tests. The results of the tests led to the choice of a wing with an increased leading-edge radius" (p. 1).

"A two-dimensional inlet-guide-vane cascade was investigated to determine the effects of ice formations on the pressure losses across the guide vanes and to evaluate the heated gas flow and temperature required to prevent Icing at various conditions. A gas flow of approximately 0.4 percent of the inlet-air flow was necessary for anti-icing a hollow guide-vane stage at an inlet-gas temperature of 500 F under the following icing conditions: air velocity, 280 miles per hour; water content, 0.9 gram per cubic meter; and Inlet-air static temperature, 00 F. Also presented are the anti-icing gas flows required with modifications of the hollow Internal gas passage, which show heat input savings greater than 50 percent" (p. 1).

Report discussing testing to determine the aerodynamic characteristics of two semispan delta-wing configurations. Information about the lift characteristics, drag characteristics, pitching-moment characteristics, and comparison with other results is provided.

"Free-flight drag measurements are presented which show the practicability of duplicating the zero-lift drag rise of many airplane configurations by simple bodies of revolution. The results confirm the transonic area rule for straight wings, and for delta and modified-delta wings with and without nacelles. The results showed that the area rule did not apply to one swept-wing configuration and an explanation is advanced to explain why it does not apply" (p. 1).

The similarity law for nonsteady, inviscid, hypersonic flow about slender three-dimensional shapes is derived. Conclusions drawn are shown to be valid for rotational flow. Requirements for dynamic similarity of related shapes in free flight are obtained. The law is examined for steady flow about related three-dimensional shapes. Results of an experimental investigation of the pressures acting on two inclined cones are found to check the law as it applies to bodies of revolution.

Report presenting an investigation in the high speed 7- by 10-foot tunnel through a range of Mach numbers to determine the lateral-control and hinge-moment characteristics of a spoiler-slot-deflector configuration on a semispan 35 degree sweptback-wing model. The results indicated that the spoiler-slot-deflector configuration with the ratio of deflector projection to spoiler projection increasing with increasing control projection has good rolling-moment effectiveness throughout the angle of attack range and throughout the high subsonic speed range.

"Flutter models of the upper and lower vertical tails of an air-to-ground missile have been tested in the Mach number range from 0.5 to 3.0. It was found that the upper surface exhibited more or less conventional flutter behavior throughout the Mach number range, whereas the lower surface experienced a sudden change in flutter mode at a Mach number of about 1.18. This change in flutter mode was accompanied by a decrease of about 50 percent in the density required for flutter to occur" (p. 1).

This report presents the results of an investigation conducted in the NACA 7 by 10-foot wind tunnel of control surfaces equipped with tabs for reducing the control forces or trimming the aircraft. Two sizes of ordinary ailerons with several sizes of attached and inset tabs were tested on a Clark y wing. Tabs were also tested in combination with auxiliary balances of the horn and paddle types, and with a frise balance aileron.

Report presenting testing of two two-blade propellers in the 8-foot high-speed tunnel for a range of blade angles and Mach numbers. The results show that changes in thrust loading due to compressibility effects were much smaller for the thin-blade propeller than for the thick-blade propeller.

From Summary: "A flight test has been conducted to determine the longitudinal stability and control characteristics of a 0.125-scale model of the McDonnell F-101A airplane for the Mach number range between 0.82 and 1.84. The variation of lift-curve slope with Mach number was gradual with a maximum value of 0.107 occurring at a Mach number of 0.95. The minimum drag coefficient (including base and internal drag) has a value of 0.020 at a Mach number of 0.87. The drag rise begins at a Mach number of 0.90, and at Mach number of 1.10 the minimum drag is 0.070. Above this Mach number there is a gradual increase in minimum drag coefficient to a value of 0.074 when the Mach number is 1.83."

The stator-blade angles in the twelfth through fifteenth stages of a 16-stage axial-flow compressor were increased 3O. The over-all performance of this modified compressor is compared to the performance of the compressor with original blade angles. The matching characteristics of the modified compressor and a two-stage turbine were obtained and compared to those of the compressor with original blade angles and the same turbine.

The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these results, the minimum altitude for safe flight through a specific gust is calculated for a particular supersonic wing of given strength and wing loading.

"A comparison is presented between the experimentally measured and theoretically calculated (by the method of NACA TN 3067) rates of roll of two rocket-propelled models with flexible rectangular wings. The comparisons show that although there are large aeroelastic losses in rolling rate, the theory predicts the actual rate of roll accurately" (p. 1).

Report presenting the results of an investigation to determine the effects of simulated skin wrinkling of the wing surface on the aerodynamic characteristics of two wing-body combinations. The lift, drag, and pitching moment of a low-wing wing-body combination with a plane triangular wing of aspect ratio 3 are presented for a range of Mach and Reynolds numbers.

"This report contains the results of tests made in the National Advisory Committee for Aeronautics variable density wind tunnel on three airplane models supplied by the British Aeronautical Research Committee. These models, the BE-2E with R.A.F. 19 wings, the British Fighter with R.A.F. 15 wings, and the Bristol Fighter with R.A.F. 30 wings, were tested over a wide range in Reynolds numbers in order to supply data desired by the Aeronautical Research Committee for scale effect studies. The maximum lifts obtained in these tests are in excellent agreement with the published results of British tests, both model and full scale" (p. 451).

Report presenting a transonic investigation made by the free-fall technique of a plane wing and a cambered and twisted wing, each with an aspect ratio 6, taper ratio of 0.5, and a sweepback of 45 degrees. Measurements were made of the loads on the exposed wings, pressures on the fuselage in the vicinity of the wing, and acceleration and angle of attack of the complete model.