Report presenting data on the thermal performance and the static pressure drop characteristics of a flattened-tube type crossflow exhaust gas and air heat exchanger. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.

Report presenting data on the thermal performance and static and total pressure drop characteristics of a fluted-type exhaust gas and air heat exchanger. Results regarding heat transfer, pressure drop, and non-isothermal pressure drop are provided.

Report presenting results of tests of the thermal performance and the static pressure drop characteristics of a flat-plate type exhaust gas and air heat exchanger. The ventilating air shroud built into the heat exchanger gives characteristics of cross flow and parallel flow.

Report presenting an analysis of the thermopile radiometer as used in the measurement of irradiation and radiant power interchange is given. The theory of the instrument when used to measure irradiation and net radiant power interchange is developed, and the precautions to be observed when using it for these measurements are presented.

Report describing power-off tests in the 6- by 6-foot test section of the stability tunnel to determine the variation of the static lateral stability characteristics with vertical-tail area, fuselage length, and wing dihedral. Two NACA 23012 rectangular wings with rounded tips and dihedral angles of 0 and 5 degrees were tested alone and in combination with three circular fuselages of different lengths. Results regarding the interference effects, effect of horizontal tail, effect of changes in fuselage length, effect of changes in vertical-tail area, effect of changes with constant tail volume, effect of changes in dihedral, and a comparison of data from 7- by 10-foot and stability tunnels are provided.

Report presenting an investigation to determine the flow losses that occur as a result of locating the axis of an intercooler at various angles with respect to the supply-duct axis and also to determine the flow pattern throughout the intercooler. The flow losses were found to be small for angles of inclination up to about 70 degrees. The distribution of flow through the intercooler also appeared to be fairly uniform up to about this angle.

Report presenting observations made of the air flow around a Martin PBM-3 flying boat. The observations are part of an analysis to aid in the determination of possible methods of reducing the air drag of the airplane. The behavior of the tufts on the hull and tip floats at various airplane speeds by still and moving pictures taken from an accompanying airplane.

"F-3 and F-4 knock data are presented for blends of 0, 20, 40, 60, and 80 percent by volume of triptane in 28-R reference fuel plus approximately 4.6 ml TEL per gallon in the final blends. For comparison of knock-limited performance, 28-R reference fuel containing 2.7 percent by volume of xylidines and leaded to 6 ml TEL per gallon is included. In order to provide information on temperature sensitivities, two sets of modified conditions were used in addition to the standard F-4 engine conditions" (p. 1).

Report presenting tests to investigate the effect of 2-percent additions of 11 aromatic amines on the knock-limited performance of AN-F-28 fuel. A total of 48 aromatic amines are being prepared for knock tests. Results regarding the knock-limited performance data, antiknock effectiveness, and knock-limited powers are provided.

Report discusses the knock-limited performance data of fuel blends containing AN-F-28, Amendment-2, fuel and a selection of aliphatic amines. The best antiknock aliphatic amines are determined through experimentation.

Report presenting knock-limited performance data obtained with several small-scale engines for blends containing nine aromatic hydrocarbons blended individually in various concentrations with selected base fuels.

Report presenting knock-limited small-scale-engine testing of several different types of aromatics mixed with selected base fuels. Data was obtained to determine the blending sensitivity, lead susceptibility, and the sensitivity of the blends to inlet-air temperature.

Report discussing tests to determine the effect of 2-percent additions of six aromatic amines on the knock-limited performance of 28-R fuel. All of the aromatic amine blends increased the performance and power of the base fuel. Different blends performed better at different fuel-air ratios.

Report presenting a combination oil sump and scavenge pump constructed to eliminate some of the oil-system difficulties in an aircraft engine that result from the aeration of the scavenged engine oil and air-lock of the scavenge pump. Information regarding test results and design recommendations are provided.

Report presenting an investigation of oscillations in the laminar boundary layer on a flat plate and their relation to transition to turbulent flow. The characteristics of boundary-layer oscillations were studied most successfully when the oscillations were artificially produced by a vibrating ribbon placed in the boundary layer near the surface. A review of theory regarding laminar-boundary-layer oscillations is provided.

Report presenting tests to study the effectiveness of small pressure differences in removing the dust boundary layer through slots in the duct wall of airplane ducts and reducing separation losses. Two-dimensional diffusers of 15 and 30 degrees included angles and some 90 degree bends were tested. The 30 degree diffuser was tested with and without an intercooler.

Report presenting pressure-distribution measurements made on the right wing of a P-39N-1 airplane at values of Mach number up to 0.80. A considerable portion of the lift was carried by components of the airplane other than the wings, and the proportion carried by the wing varies considerably with Mach number. Results regarding the variation of wing loads and moments with Mach number, internal wing pressure, and airplane lift-curve slope are provided.

Report presenting an investigation of the flying qualities of a Hawker Hurricane airplane. Thirteen flights and approximately 17 hours of flying time were required to complete the tests, which included extensive measurements of stability, controllability, and stalling characteristics. The results were similar to the flying qualities of other previously studied pursuit airplanes.

"A method for the estimation of the maximum stresses around a small rectangular cut-out in a sheet-stringer panel loaded in pure shear is presented; this method is based on a simplified application of the shear-lag theory. Comparisons indicate that the experimental maximum stringer and shear stresses agree reasonably well with the predictions, provided that neither the length nor the width of the cut-out is greater than the half-width of the panel" (p. 1).

Report presenting an investigation of a method of studying the longitudinal dynamic stability of flying-boat-hull models, as instability may be encountered when flying a flying boat on the water at high speeds and high trim angles, especially upper-limit porpoising and skipping. A method is described for carrying out generalized experimental studies of the longitudinal dynamic stability of flying-boat-hull models.

Report presenting a practical and relatively rapid method of compensating for shear lag in box-beam analysis with accuracy sufficient for design purposes. Effectiveness curves for box beam elements are derived for an ideal, symmetrical structure. Tabular computation forms for rapid, accurate calculations of axial stresses, shear center, and shear stresses for beam with shear lag are induced.

"Following a brief history of the NACA investigation of jet-propulsion, a discussion is given of the general investigation and analyses leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight-performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made" (p. 1).

Report presenting testing of several designs of nitrided-steel piston rings under variable conditions of output. Testing indicated the importance of good surface finish and conformity of the ring to the bore. Results regarding temperature tests, single-cylinder-engine tests, and multicylinder-engine tests are provided.

Report presenting the development of a method of evaluating the epsilon-integral occurring in the arbitrary airfoil theory of Theodorsen by retaining higher order terms in the Taylor expansion and by use of Simpson's rule. Formulas are given for routine calculation of the epsilon-integral and for the necessary computational coefficients.