Report presenting the performance of a 22-inch-diameter pulse-jet engine using a net of low-loss modified air valves at ram pressures equivalent to simulated flight speeds. Results regarding combustion-air weight flow, flight thrust, maximum combustion-chamber pressure, specific fuel consumption, pressure cycle, and valve life are provided.

Report presenting an investigation in the 20-foot propeller-research tunnel to determine the effect of variations in angle of pitch on the aerodynamic characteristics of several propeller combinations. The combinations investigated included two-, three-, four-, and six-blade single-rotating propellers and a six-blade dual-rotating propeller on a nacelle with four angles of thrust axis. The propulsive efficiency was found to decrease as the angle of pitch increased.

Report presenting an investigation of the use of ethylene dibromide to leaded fuel in order to prevent lead deposits within the cylinder. It is meant to react with lead to form volatile compounds that will be scavenged with exhaust gases. Results regarding the lead deposits, knock-limited effective pressures, performance, and temperatures are provided.

Report presenting an analysis of the failure of adhesive bonds and its relation to boundary stress concentrations. A variety of material combinations, including metals and plastics, were examined and stress tested. The method of computing the thermal coefficients is applied to mixtures and especially to reinforced plastics.

Report presenting a simple equation that can be used to facilitate the appraisal of the conventional jet as a means of propulsion. The equation can be used to estimate the performance of a large variety of aeropropulsive devices. The results using this equation indicate that attainable propulsive efficiencies at high speeds below sonic velocity are certain to be lower than is common at low speeds with the conventional propeller.

"Column and plate compressive strengths of 24S-T aluminum-alloy sheet were determined both within and beyond the elastic range from tests of thin-strip columns and from local-instability tests of formed Z-end channel-section columns. These tests are the first of a series in an extensive research investigation to provide data on the structural strength of various aircraft materials. The results, which are presented in the form of curves and charts that may be used in the design and analysis of aircraft structures, supersede preliminary results published previously" (p. 1).

Report presenting the results of an investigation of the fatigue characteristics of spot-welded 24S-T aluminum alloy. The static shear strength of spot welds in lap joints of 24S-T alclad increases with increasing sheet thickness for thicknesses in the range of 0.025 inch to 0.032 inch.

Report discusses the results of testing on "10-inch shear panels of 24S-T aluminum alloy with 1.5 inch holes to determine the stress concentration at static rupture and the deformation characteristics" (from Summary). The strength of the perforated specimens is compared to the solid specimens and the critical stresses are computed. The stress at which permanent set occurs was also measured.

Report presenting testing to investigate the effects of 2-percent additions of nine aromatic amines on the knock-limited performance of AN-F-28 (28-R) fuel. The p-toluidine and p-tert-butylaniline gave the best overall improvement in the knock-limited power of the fuel.;

Report presenting tests conducted with an air-cooled cylinder on two fuels rated at approximately 100-octane number by the C.F.R. aviation method with and without a 40-percent addition of an aromatic mixture. The aromatic mixture consisted of 50 percent toluene, 37.5 percent xylene, and 12.5 percent benzene. Results regarding engine performance and engine temperature are provided.

Report presenting testing to determine the solubilities in gasoline at low temperatures of 15 aromatic amines from the NACA exploratory program as antiknock additives. The solubility data is summarized in a table by interpolating or extrapolating experimental results to obtain solubility at -60 degrees Celsius.

Report presenting a series of outdoor tests to determine the static-thrust and torque characteristics of single- and dual-rotating propellers for use in aircraft propeller design and in take-off performance estimation.

Two airfoil plans were used for propeller blades. One is modified Clark Y section designed for structural reliability and the second an NACA 16 airfoil section designed to produce minimum aerodynamic losses. At low air speeds, the propeller designed for aerodynamic effects showed a gain of from 1.5 to 4.0 percent in propulsive efficiency over the conventional type depending on the pitch. Because of the numerous variables involved, the effect of each one on the aerodynamic characteristics of the propellers could not be isolated.

From Summary: "A theoretical investigation was made of the behavior of a cantilever beam in rotational motion about a transverse axis through the root determining the stresses, the deflections, and the accelerations that occur in the beam as a result of the arrest of motion. The equations for bending and shear stress reveal that, at a given percentage of the distance from root to tip and at a given trip velocity, the bending stresses for a particular mode are independent of the length of the beam and the shear stresses vary inversely with the length. When examined with respect to a given angular velocity instead of a given tip velocity, the equations reveal that the bending stress is proportional to the length of the beam whereas the shear stress is independent of the length."

"A correlation of what are believed to be the most reliable data available on duct components of aircraft power-plant installations is presented. The information is given in a convenient form and is offered as an aid in designing duct systems and, subject to certain qualifications, as a guide in estimating their performance. The design and performance data include those for straight ducts; simple bends of square, circular, and elliptical cross sections; compound bends; diverging and converging bends; vaned bends; diffusers; branch ducts; internal inlets; and an angular placement of heat exchangers" (p. 1).