"The results are given of an investigation of some of the limitations that now prevent increases in the temperature level of engine cylinder heads, and a review of previous work in the field is included to supplement these results. Attention was given, in particular, to the effects of fuel knock and surface ignition on cylinder temperatures and the effects of cylinder temperatures on performance. Data were obtained from a Wright C9GC air-cooled cylinder and from a Lycoming O-1230 liquid-cooled cylinder" (p. 1).

"Vibrations of rotary-wing aircraft may derive their energy from the rotation of the rotor rather than from the air forces. A theoretical analysis of these vibrations is described and methods for its application are explained herein" (p. 1). Information about self-excited speed range and shaft-critical speed are provided for any rotor with more than two blades.

Report presenting wind tunnel testing of four full-scale seaplane floats to determine the aerodynamic characteristics of the floats and to evaluate several drag-reducing refinements. Four floats were investigated; two differed only in external details like flush rivets, while one was the type used on twin-float installations. The variation of lift, drag, and pitching moment with pitch angle are presented for each float.

Report presenting a direct comparison between the observed and the calculated longitudinal dynamic stability of a particular dynamic model of a flying boat moving on the water. Good agreement was obtained between experiment and theory for trim angles in the vicinity of lower limit, at one speed a little above the hump.

Report presenting data from tests conducted on full-scale propellers with 3155 blade design, which have been used to construct a set of propeller thrust charts for use in the calculation of take-off performance. By using the charts, the thrust of modern single- and dual-rotating propellers may be easily and rapidly calculated through the entire take-off range.

Report presenting a method for obtaining exact potential-flow patterns in a compressible fluid. The method is based on a complex-function theory developed for the solutions of the simultaneous first-order partial differential equations in the hodograph variables.

Report presenting testing to obtain experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. Testing occurred over a wide range of air flows and density altitudes.

Report presenting an analytical study of the influence of full-span slotted and Fowler flaps on the requirements for horizontal tail surfaces. The elevator deflection required to land at three-point attitude, elevator deflection required to stall the airplane at altitude, and permissible center-of-gravity range have been calculated for a fighter-type airplane.

Report presenting column and plate compressive strengths of extruded 24S-T aluminum alloy determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of a research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

Column and plate compressive strengths of extruded 24S-T aluminum alloy were determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-,and channel-section columns. These tests are part of an extensive research investigation to provide data on the' structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.

Report presenting column and plate compressive strengths of extruded 75S-T aluminum alloy both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

To determine the effect of piston-head temperature on knock-limited power, tests were made in a supercharged CFR engine over a range of fuel-air ratios from 0.055 to 0.120, using S-3 reference fuel, AN-F-28, Amendment-2, aviation gasoline, and AN-F-28 plus 2 percent xylidines by weight. Tests were run at a compression ratio of 7.0 with inlet-air temperatures of 150 F and 250 F and at a compression ratio of 8.0 with an inlet-air temperature of 250 F. All other engine conditions were held constant.

Report presenting tests of the flow of air through brass tubes with the friction coefficient and incompressible flow relation as the main focus. The analytical relation between friction coefficient, tube length, and Mach number is shown for flow without shock and the conditions for flow with and without shock are delimited.

From Introduction: "This paper contains data on the mechanical properties of sand-cast test bars having a considerable range in zinc, magnesium, and copper content and more detailed data on the properties and foundry characteristics of an aluminum-zinc-magnesium-copper alloy having a preferred composition for high strength and ductility."

Report discusses the results of yawing tests on a model of the complete hull of the XPB2M-1. The tests indicated that there was a tendency toward directional instability in the vicinity of the hump. The researchers concluded that at a certain range, the curves of yawing moment are discontinuous, and this has led to difficulty in preliminary test flights.

Report presenting an investigation in the 7- by 10-foot wind tunnel of several arrangements of a plug-type spoiler-slot aileron on a tapered wing model of a typical fighter airplane with a full-span slotted flap. When the aileron is deflected, the plug projects from the upper surface of the wing as a spoiler and makes a slot appear behind the spoiler.

Report presenting determination of air-flow quantity in front of and behind three orifice plates to determine the errors introduced in the quantity measurements by the turbulence behind the orifice plates. For the orifice plates tested, the results showed that the measurements must be taken 40 to 60 hole diameters downstream from the plates to ensure accuracy.

Report presenting an analysis of the effect of cooling-air blowers on thrust power using an assumed airplane. Results indicated that when aviation-engine heat exchangers are used above their design altitude, blowers may be used to give additional available pressure and to increase jet thrust. Results regarding airplane speed, altitude, fin width, physical significance of the heat cycle, and thermodynamic efficiency are provided.

Report presenting testing of a mock-up of a pursuit airplane in the full-scale wind tunnel and the effects of propeller operation and flap deflection on the aerodynamic characteristics of the wing-fuselage combination and of the horizontal tail. The results indicate that with the flap deflected, the propeller-operating conditions cannot be directly determined from the propeller-removed lift coefficient.

Report discusses the results of bending tests on an open box beam designed to fail on the highly cambered tension side. Results in the elastic range and ultimate-strength test are provided. The stringer stresses near the root were in fair agreement with stresses calculated by shear-lag theory and the ultimate tensile strength developed by the beam was only a little higher than the tensile yield stress of the material.

An investigation to determine the feasibility of measuring surface contours with an aerial-mapping contour finder on stereoscopic electronic micrographs of replicas of metal surfaces. Results regarding the measurement of stereoscopic electron micrographs, measurement of surface contours, possible sources of low stereographic values, and limitations on stereoscopic-contour measurements are provided.

From Summary: "The independent variables considered in the analysis included stress-concentration factor, stress-load relation, wing loading, design and cruising speeds, design gust velocity, and airplane size. Several methods for estimating fatigue life from gust frequencies are discussed."

Report presenting a technique of testing wind tunnel powered models developed as a result of experience gained in the investigation of the static longitudinal and lateral staiblity and control characteristics of several powered models in the 7- by 10-foot wind tunnel. A discussion of the conditions to be investigated, methods of presenting and interpreting the data, and a suggested operating technique are given.

Report presenting an investigation of a plain aileron and a balanced aileron on a tapered wing with full-span duplex flaps, which consisted of an inboard NACA slotted flap and an outboard balanced split flap. Increments of maximum lift coefficient of 0.82 and 1.04 were obtained from the inboard flap alone and from the duplex-flap combination.