Report presenting an investigation on a transonic bump to determine the aerodynamic characteristics of a series of triangular wings. Four basic triangular-wing plan forms with different aspect ratios, taper ratios, and combinations of tip clipping were tested over a range of Mach and Reynolds numbers. Results regarding angle of attack, drag coefficient, pitching-moment coefficient with lift coefficient, and various curves are provided.

From Introduction: "In the analysis given herein, which was made at the NACA Lewis laboratory, the expression for eddy diffusivity given in reference 1 is modified in order to account for the effect of kinematic viscosity in reducing the turbulence in the region close to the wall. The effects of variable viscosity and of length-to-diameter ratio are also investigated."

An experimental study is presented of the pressure fluctuations near jet exhaust streams made during unchoked operation of a turbojet engine and a 1-inch-diameter high-temperature model jet and during choked operation of various sizes of model jets with unheated air. The tests for unchoked operation indicate a random spectrum of rather narrow band width which varies in frequency content with axial position along the jet. Pressure surveys from the model tests along lines parallel to the 15 degree jet boundary indicate that the station of greatest pressure fluctuations is determined by the jet velocity and the radial distance, with a tendency of the maximum to shift downstream as either parameter is increased.

Report presenting an investigation to evaluate the overall performance characteristics of several annular nose inlets in the supersonic wind tunnel at a Mach number of 3.85. The four experimental configurations investigated consisted of a one-cone, a one-cone with low angle cowl, a two-cone, and an isentropic inlet. Results regarding the internal-flow performance, force measurements at zero angle of attack, overall performance comparison at zero angle of attack, and angle-of-attack force measurement are provided.

Report presenting an investigation of a 1/19-scale model of an unswept-wing trainer airplane in the 20-foot free-spinning tunnel to determine the rocket spin-recovery characteristics of the model for comparison with available full-scale-airplane results. A rocket was attached to each wing tip to fire in a direction to apply an antispin yawing moment about the Z body axis. Results regarding the full-scale spin recoveries by rockets, model spin recoveries by rudder reversal, model spin recoveries by rockets, and mass changes associated with installation of emergency device are provided.

Note presenting an investigation of some of the possible mathematical troubles that may occur in the iterative procedure so much in use in present-day aerodynamics. The analysis indicates the general undesirability of determining the velocity potential or the stream function in the form of a series whose coefficients are analytically developed in a power series of some parameter.

Report presenting a soap-bubble, constant-pressure method to measure laminar burning velocities of some hydrocarbon-nitrogen-oxygen mixtures. Results regarding the evaluation of the soap-bubble method of measurement and burning velocities of hydrocarbon-oxygen-nitrogen mixture are provided.

Note presenting an analysis of the propulsive thrust and specific impulse attainable by cooling aircraft surfaces with liquefied or solidified gases with vaporization temperatures lower than the equilibrium surface temperature. Use of coolant vaporization as the sole means of propulsion yields low specific impulses at low speeds.

Report presenting a study of the flow distribution throughout the passage of a rotating impeller, and the results are presented in the form of relative velocity and relative pressure loss contours. The loss and velocity distributions indicate that secondary flows in the boundary layer tend to shift the low-energy air toward the blade suction within the passage. Results regarding the overall performance, performance within the passage, secondary flow and clearance effects, and a comparison with the hot-wire anemometer surveys are provided.

Note presenting the effect of inclination of the airstream on the static pressure measured by two essentially similar service pitot-static tubes and by one of those tubes with three modified orifice arrangements as determined in flight. Results regarding initial calibrations at Mach numbers from 0.20 to 0.24 and the final orifice configuration are provided.

"The analogy between a ball rolling over a contoured surface and a pitching and yawing aircraft is developed. Test results from a model representing a missile with linear moment characteristics are presented to verify the analogy. Several examples of the behavior of nonlinear systems are also given" (p. 1).

Report presenting some information relative to the prediction of shock-induced boundary-layer separation. Experimental results showing the effects of Reynolds number and Mach number on the separation of both laminar and turbulent boundary layers are given and compared with results obtained by available methods for predicting separation.

Report presenting an investigation of laminar, transitional, and turbulent boundary layers in a subsonic wind tunnel at two Mach numbers at various Reynolds numbers and stations along a flat plate. Comparisons are made of the density profiles obtained with a total-pressure probe of small frontal opening and by means of an X-ray absorption method and, in a few cases, by using interferometer data.

From Summary: "A flight investigation has been made of the practical problems associated with the use of porous-leading-edge suction. The wing leading edge of the test airplane was porous over approximately 83 percent of the span and the first 8 percent of the chord on the upper surface. Various other extents of suction area within these limits were also tested."

From Introduction: "The purpose of this report is to present the results of the analytical investigation of the turbine of reference 1 to indicate the extent to which the various turbine losses affect the turbine efficiency over the range of performance."

From Summary: "As part of an overall program for the experimental investigation of large-scale jet nozzles, a preliminary evaluation of the internal performance characteristics of several variable-throat extended-plug-type nozzles was obtained over a range of nozzle pressure rations from 2 to 15 with nozzle throat variations as great as 2:1. The extended-plug nozzle attained peak thrust coefficients as high as those which have been attained with fixed-geometry convergent-divergent nozzles. The thrust coefficients of the extended-plug nozzles were relatively insensitive to both nozzle pressure ratio and throat area over the range investigated."

Report discussing testing of a helicopter rotor powered by pulse-jet engines located at the rotor-blade tips. The basic hovering characteristics of the rotor and propulsive characteristics of the pulse-jet engine were obtained at a range of engine speeds with the engines rigidly fixed to the blade tips and with the engines free to pivot. Measurements were also taken to determine the effect of inlet blockage on the power-off drag of the jet engines and the noise intensity in the vicinity of operating engines.

Memorandum reporting the tensile and crazing properties for five cast polymethy lmethacrylate sheets in which the molecular weight of the resin was 90,000, 120,000, 200,000, 490,000, and 3,160,000. Both stress crazing and stress-solvent crazing tests were conducted. Results regarding the standard tensile tests, stress-solvent crazing tests, and discussion of failure and crazing are provided.

Report presenting an investigation of the performance of an annular-diffuser-tailpipe combination with an abrupt area expansion with and without flow controls in the form of suction, injection, and vortex generators. Results regarding the inlet measurements, longitudinal static-pressure distribution, radial distributions, and mean performance coefficients are provided.

"The explosion limits of five alkylsilanes were determined as a function of temperature and composition at a pressure of 1 atmosphere. Over a fuel concentration range of 2 to 10 percent, the lowest temperatures (zero C) below which explosion did not occur for the five fuels studied were: tetramethylsilane (CHsub3)sub4Si, 450 degrees; trimethlysilane (CHsub3)sub3SiH, 310 degrees;dimethylsilane (CHsub3)sub2SiHsub2, 220 degrees; methylsilane CHsub3SiHsub3, 130 degrees; and vinylsilane Hsub2C=CH-SiHsub3, 90 degrees. Explosion limits for hydrocarbons analogous to these silanes fall in a temperature range of 500 degrees to 600 degrees C" (p. 1).

From Summary: "Modifications A and B of impeller model MFI-1 and A, B, and C of impeller model MFI-2 were investigated experimentally in an attempt to determine what allowance in blade height should be made for boundary layer and viscous losses in an impeller designed for isentropic compressible flow. A gradual increase in blade height was arbitrarily made from inlet to outlet in anticipation of a gradual build-up of boundary layer. Apparently there was a rapid build-up of boundary layer near the inlet in the experimental case rather than a gradual one. Therefore, the proper allowance for boundary layer cannot be described from the data obtained."

Report presenting an analysis of two turbojet engines, including the component performance of the compressors and turbines, in order to determine the effect on engine performance and operation of bleeding the compressor to furnish cooling air for the turbine rotor blades. Results regarding the compressor and turbine performance characteristics and engine performance characteristics are provided.

Report presenting an experimental investigation of external airfoils, known as paddle-control surfaces, as the longitudinal control device on a triangular wing of aspect ratio 2. The lift, drag, pitching moment, and hinge moment were obtained for a variety of Mach numbers.

Report presenting a comparison of the hydrodynamic impact loads and motions encountered in testing a V-step and a transverse-step flat-bottom hydro-ski with beam loadings of about 4.5. Testing occurred in smooth water over a range of velocities, flight-path angles, and fixed trims. Results regarding time histories of draft, vertical velocity, and vertical acceleration, impact lift coefficient, draft coefficient, and time coefficient for rebound are provided.