From Introduction: "The purpose of this paper is to describe one of the means developed for measuring this quantity on a given airplane type- a trailing arm with wheel. A prototype velocity indicator was tested in the Langley impact basin to determine its accuracy. A description of the operation of this type of vertical-velocity indicator, the results of the impact-basin and flight tests, and general evaluation of the indicator are presented herein."

"A procedure for analyzing statically indeterminate trusses in the plastic stress range is presented which is applicable to trusses having any number of redundant members. A numerical example is used to illustrate the procedure" (p. 1).

Report presenting a procedure for predicting the upwash components of the upflow angles in the region above or below the wing-chord planes of sweptback wing-fuselage-nacelle combinations. Comparisons of predicted and measured upflow angles are shown for six semispan models with 40 degree sweptback wings.

Report presenting calculation studies to evaluate the influence that wing bending flexibility has on the structural response to gusts for three twin-engine transports and one four-engine bomber. The manner in which dynamic response factors for acceleration and bending moment vary with different assumed airplane operational factors is shown.

Report presenting an investigation of the observed discrepancy at supersonic speeds between theoretical and apparent experimental average flat plate friction-drag coefficients calculated from boundary layer total-pressure surveys. Some of the qualities investigated included the effects of the total-pressure probe, heat transfer through the leading-edge region, change in leading-edge radius and strength of the leading-edge wave, possible early transition to turbulent flow, and the slight streamwise pressure gradient in flat plate flow were investigated for plates with very sharp leading edges.

Flight tests were made of the flying qualities of an F-47D-30 airplane to determine the longitudinal stability and control and stalling characteristics. The results indicated that the airplane was unstable with stick free in any power-on condition even at the most forward center-of-gravity position tested.

As a rule, a division of the turbulent boundary layer is admissible: a division into a part near the wall, where the flow is governed only by the wall effects, and into an outer part, where the wall roughness and the viscosity of the flow medium affects only the wall shearing stress occurring as boundary condition but does not exert any other influence on the flow. Both parts may be investigated to a large extent independently. . The theoretical considerations give a cue how to set up, by appropriate experiments and their evaluation, generally valid connections which are required for the approximate calculation of the turbulent boundary layer according to the momentum and energy theorem.

Report presenting a method for quickly estimating the separation point of a laminar boundary layer in a compressible flow. The method should be usable for any two-dimensional flow in which classical boundary-layer assumptions are satisfied. Results obtained from a variety of calculations indicate that for all velocity gradients, the amount of velocity recovery possible before laminar separation occurs decreases as Mach number increases.

Note presenting a suggestion for classifying the compressible potential flows according to the location and number of singularities in the subsonic region of the hodograph plane, which seems to offer a convenient criterion for systematic investigation of these flows with Chaplygin's original method. The primary object of the paper is to present and analyze a few useful solutions of compressible potential flow with the exact gas law.

Note presenting a survey of the 1200 degrees Celsius isothermal sections of the iron-nickel-molybdenum and the cobalt-iron-molybdenum ternary systems. The phases occurring in the systems were identified by means of x-ray diffraction and by etching methods, and the phase boundaries at 1200 degrees Celsius were determined microscopically, using the disappearing phase method with quenched specimens. Results regarding the specific phases and phase diagrams are provided.

Equations are presented for the attenuation characteristics of several types of mufflers. Experimental curves of attenuation plotted against frequency are presented for 77 different mufflers and the results are compared with theory. The experiments were made at room temperature without flow and the sound source was a loud-speaker. A method is given for including the tail pipe in the calculations. The application of the theory to the design of engine-exhaust mufflers is discussed, and charts have been included for the assistance of the designer.

Report presenting an analysis to determine the pressure distribution, span loading, and rolling moment due to small angles of sideslip at supersonic speeds for a series of thin, sweptback, tapered wings with wing tips parallel to the axis of wing symmetry. Three basic series of Mach numbers and plan-form combinations are considered, all of which have supersonic trailing edges in conjunction with both leading edges subsonic, one leading edge subsonic and one leading edge supersonic, and both leading edges supersonic.

From Introduction: "Afterburning is well established as an effective means of increasing the thrust of a turbojet engine. In order to obtain the maximum thrust from an afterburner, it is necessary to burn to the highest temperatures possible (reference 1). At these high temperatures, material limitations (reference 2) necessitate the installation of cooling systems to permit safe and reliable operation."

From Summary: "The investigation of air-launched ram-jet engines has been extended to include a study of models with a nominal design free-stream Mach number of 2.40. These models require auxiliary thrust in order to attain a flight speed at which the ram jet becomes self-accelerating. A rocket-boosting technique for providing this auxiliary thrust is described and time histories of two rocket-boosted ram-jet flights are presented. In one flight, the model attained a maximum Mach number of 2.20 before a fuel system failure resulted in the destruction of the engine. Performance data for this model are presented in terms of thrust and drag coefficients, diffuser pressure recovery, mass-flow ratio, combustion efficiency, specific fuel consumption, and over-all engine efficiency."

Ignition delays of alkyl thiophosphites were obtained in a modified open-cup apparatus and a small-scale rocket engine apparatus. At -40 F, mixed alkyl thiophosphites gave short delays with white fuming nitric acid containing 2 percent water and red fuming nitric acids of widely varying compositions. At -40 F and higher, triethyl trithiophosphite blended with as much as 40 percent n-heptane gave satisfactory self-igniting properties at temperatures as low as -76 F.

"The equations presented in this report give the interference on the trailing-vortex system of a uniformly loaded finite-span wing in a circular tunnel containing partly open and partly closed walls, with special reference to symmetrical arrangements of the open and closed portions. Methods are given for extending the equations to include tunnel shapes other than circular. The rectangular tunnel is used to demonstrate these methods. The equations are also extended to nonuniformly loaded wings" (p. 361).

Report of theoretical values of performance parameters for liquid hydrogen and flourine as a rocket propellant for a wide range of fuel-oxidant and expansion ratios. Parameters computed include specific impulse, combustion-chamber temperature, nozzle-exit temperature, equilibrium composition, mean molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, coefficient of viscosity, and coefficient of thermal conductivity.

Theoretical values of performance parameters for liquid hydrogen and liquid fluorine as a rocket propellant were calculated on the assumption of equilibrium composition during the expansion process for a wide range of fuel-oxidant and expansion ratios. The parameters included were specific impulse, combustion-chamber temperature, nozzle-exit temperature, equilibrium composition, mean molecular weight, characteristic velocity, coefficient of thrust, ration of nozzle-exit area to throat area, specific heat at constant pressure, coefficient of viscosity, and coefficient of thermal conductivity. The maximum value of specific impulse was 364.6 pound-seconds per pound for a chamber pressure of 300 pounds per square inch absolute (20.41 atm) and an exit pressure of 1 atmosphere.

Report presenting testing of a wing with 0 degree sweepback of the 0.25-chord line in combination with a body of revolution at Mach numbers from 0.60 to 1.11 for angles of attack up to 24 degrees. Results regarding lift characteristics, pitching moment, drag characteristics, and lift-drag ratio are provided.

Report presenting an investigation in a duct system with fully developed pipe flow to determine the effects of vortex generators on the performance of a diffuser with whirling inlet flow. Testing was made with three different inlet whirl angles and rectangular, noncambered airfoils that varied in chord, span, angle setting, number, and location. Results for the 20.6 degree inlet whirl angle, 15.2 degree inlet whirl angle, 0 degree inlet whirl angle, and effect of inlet whirl angle on diffuser performance are provided.

Report presenting spanwise lift distributions, lift coefficients, spanwise centers of pressure, shifts in aerodynamic center, coefficients of damping in roll, aileron rolling-moment coefficients, and rates of steady roll per unit aileron deflection have been calculated for nine M-, W-, and delta wings, as well as for comparable ordinary sweptforward, unswpet, and sweptback wings. Certain qualitative conclusions are drawn concerning the plan forms most suitable from the aeroelastic point of view. M and W plan forms exist which are superior aeroelastically and structurally to ordinary swept wings.

Memorandum presenting a comparison of the aerodynamic characteristics and flow phenomena at transonic speeds for a 45 degree sweptback wing mounted alternatively on a cylindrical body and an indented body. Indentation eliminated the zero-lift drag rise associated with the wing at a Mach number of 1. Results regarding the lift, drag, and pitching moment, flow surveys, level-flight characteristics, and flow phenomena are provided.

Report presenting an investigation to determine the performance characteristics of a double-shroud cooling-air ejector configuration. Two convergent nozzles were used to simulate a specific manufacturer's iris-type variable-area nozzle in the open and closed positions. The investigation had four phase: (1) obtaining performance with no secondary or tertiary air flow, (2) determining the tendency for backflow to occur in either cooling-air passage, (3) determining the sensitivity of flow in one passage to the other, and (4) obtaining pumping and thrust characteristics with secondary and tertiary air flow.

Report presenting two-group criticality calculations for sodium-hydroxide-cooled, moderated, and reflected reactors for various concentrations and compositions of reactor fuel-element structural material. The investigation was performed in order to determine the applicability of the fuel properties to power a nuclear aircraft. Results regarding the specific reactor calculations, reflector savings, criticality generalization, typical neutron flux and heat-generation distributions, static stability characteristics and excess uranium requirements, reactor heat-transfer characteristics, and airplane and turbojet cycle characteristics are provided.