Memorandum presenting a single J33 combustor and an experimental tubular combustor incorporating a fuel vaporizer as operated with gaseous hydrogen at temperatures slightly above the boiling point of the fuel. Data were obtained to explore possible effects of the fuel temperature on combustor performance and on the control and measurement of fuel flow.

Report discussing testing to determine the drag characteristics at zero lift of a wing with a circular-arc airfoil section with a maximum thickness of 9 percent chord. The results were compared to previous testing on an NACA 65-009 airfoil. It was found that the NACA airfoil had lower drag coefficients than the circular-arc airfoil tested in this experiment.

Report presenting an investigation of the pressure distribution over a leading-edge flap in the 19-foot pressure tunnel. Testing occurred on 42 degree and 52 degree sweptback wings of NACA 64(sub 1)-112 sections, with the 42 degree wing being used in conjunction with a circular cross-section fuselage in a high-wing combination.

The use of ceramic material for rocket nozzles and the effectiveness of preventing oxidation and erosion of graphite nozzles by chrome-plating the internal surface were investigated. A supported ceramic nozzle, cracked by initial operation, was operated a second time without further cracking or damage. Chrome-plating the internal surface of graphite nozzles effectively prevented oxidation and erosion that occurred during operation with unprotected graphite.

Memorandum presenting tests in the 9-inch supersonic tunnel to investigate the factors that determine the magnitude of the wing-tail interference effects on the static longitudinal stability of supersonic missile configurations with low-aspect-ratio, tandem, cruciform lifting surfaces and to develop a missile configuration with a minimum variation in static margin due to wing-tail interference effects.

Report presenting boundary-layer measurements on rocket-powered free-flight models to determine average skin-friction coefficients. The test body, NACA RM-10, was a fin-stabilized parabolic body of revolution of fineness ratio 12.2 with a blunt base to provide space for a rocket jet. Results regarding the skin-friction and boundary-layer profiles and experimental and theoretical curves are provided.

Memorandum presenting lift, drag, and pitching-moment data and some static rolling-moment data are presented for missile configurations having wing-tail-span ratios equal to and less than 1. The configurations include variations in wing and tail plan forms, wing-tail-span ratios, body length, and nose shape.

Report presenting the effects of a low-speed wind-tunnel investigation to determine the effects of vertical-fin location and area on the static and rotary lateral stability characteristics of semitailless airplane models. Results regarding straight flow, yawing flow, and rolling flow are provided.

Report presenting local coefficients of convective heat transfer as measured from skin temperature along the body of an RM-10 NACA research missile, which consisted of a parabolic body of revolution. Results regarding recovery factors, adiabatic wall temperatures, Nusselts, Prandtl, and Reynolds numbers, and boundary-layer transition are provided.

The bending stresses in the covers of box beams or wide-flange beams differ appreciably from the stresses predicted by the ordinary bending theory on account of shear deformation of the flanges. The problem of predicting these differences has become known as the shear-lag problem. The first part of this paper deals with methods of shear-lag analysis suitable for practical use. The second part of the paper describes strain-gage tests made by the NACA to verify the theory. Three tests published by other investigators are also analyzed by the proposed method. The third part of the paper gives numerical examples illustrating the methods of analysis. An appendix gives comparisons with other methods, particularly with the method of Ebner and Koller.

This document contains reproductions of technical papers on some of the most recent research results on aircraft structures from the NACA Laboratories. These papers were presented by members of the staff of the NACA Laboratories at the NACA conference held at the Langley Aeronautical Laboratory March 7, 1951. The purpose of this conference was to convey to those involved in the study of aircraft structures these recent research results and to provide those attending an opportunity for discussion of these results.

Report presenting testing of a 6.5-inch-diameter ramjet engine with a design Mach number of 2.13 and a short-flame-length combustor. Performance characteristics are provided for a range of Mach numbers and fuel-air ratios. Results regarding thrust, drag tests, static pressure, and combustion efficiencies are provided.

Memorandum presenting a study of the relationship between the static and dynamic properties of heat-resistant alloys at high temperatures. An auxiliary objective is to provide a better basis for evaluating the results from the various types of fatigue machines.

Experimental data are presented on the variation of the modulus of rigidity in the temperature range -20 to +50 degrees C. of a number of metals which are of possible use for elastic elements for aircraft and other instruments. The methods of the torsional pendulum was used to determine the modulus of rigidity and its temperature coefficient for aluminum, duralumin, monel metal, brass, phosphor bronze, coin silver, nickel silver, three high carbon steels, and three alloy steels. It was observed that tensile stress affected the values of the modulus by amounts of 1 per cent or less.