Report discusses an investigation into static pressures in subsonic and supersonic flow over an airplane wing as measured by static-pressure tubes, a static-pressure belt, and orifices flush with the wing surface. The results obtained from the three types of measuring devices and a comparison to theoretical calculations are presented.

Report discusses the results of testing on the pressure distribution at several longitudinal sections of the vertical tail surface of the Curtiss P-40K airplane at various angles of attack and angles of yaw and with the propeller removed and propeller operating. Results regarding the chordwise pressure distributions, effects of propeller operation on the spanwise distribution of normal-force coefficient, total normal-force coefficients, and effect of propeller operation on the variation of vertical-tail normal-force coefficients are presented.

Report discusses the results of testing to determine the maximum rates of control stick (elevator) motion and corresponding maximum stick forces that could be exerted based on experiments with several pilots. The main topics explored were the comparison of the maximum rates of push and pull, maximum rates of push and pull when a mental restriction was placed on the pilot, and maximum rates at which the pilot though he would apply the elevator control forces versus the actual application of forces. Information about experimental procedures and the rig the testing occurred on is included.

Report discusses an analysis and preliminary design of a control linkage that varies automatically with dynamic pressure. The advantages of the device, including greater lateral control than a fixed control linkage without additional aerodynamic balance, are detailed. The effect of variable linkage on lateral-control characteristics is also described.

"Formulas for the calculation of hinge-moment characteristics of an elevator with a spring tab have been developed in terms of basic aerodynamic parameters, spring stiffness, and airspeed. The formulas have been used in a study of the stick-force gradients on a pursuit airplane equipped with an elevator with a spring tab. Charts are presented showing the variation of stick-force gradient in accelerated flight over a large range of speed and the complete range of spring stiffness for various center-of-gravity locations, altitudes, and airplane sizes" (p. 1).

"The effects of changes in aileron rigging between 2 deg up and 2 deg down on the stick forces were determined from wind-tunnel data for a finite-span wing model. These effects were investigated for ailerons deflecting equally in both directions and linearly with stick deflection. Data were analyzed for a Frise, a sealed internally balanced, and a beveled-trailing-edge aileron" (p. 1).

Report discusses an investigation that was conducted to compare the strength and tightness of machine-countersunk flush-riveted joints assembled with NACA flush rivets and a type of commercial flush rivet. A comparison was also generated between the strength and tightness of counterpunched flush-riveted joints assembled with the same types of rivet. NACA's flush-riveted joints tended to be stronger and tighter than the commercial joints.

Report discusses the results of an investigation into the tightness, shear strength, tensile strength, and life under pulsating loads of hollow, hydraulically expanded rivets made of 17S-T aluminum alloy. The countersunk-head rivets with inserts had a much higher maximum load in shear than the modified-roundhead rivets, which did not have inserts.

Report discusses the results of an investigation into the effectiveness of water injection into the combustion end zone of a spark-ignition engine cylinder for the suppression of knock. The injection angle was found to be very important for obtaining maximum results. The results of various angles and amounts of water were examined.

Engine tests, together with estimates made at Langley Memorial Aeronautical Laboratory, indicate that a 25-percent increase in take-off power can be obtained with present-day aircraft engines without increasing either the knock limit of the fuel or the external cooling requirements of the engine. This increase in power with present fuels and present external cooling is made possible through the use of an internal coolant inducted through the inlet manifold. Estimates on aircraft indicate that this 25-percent increase in power will permit an approximate usable increase of 8.5 percent in the take-off load of existing military airplanes. This increase in load is equivalent to an increase in the weight of gasoline normally carried of between 30 and 65 percent.

Report discussing some calculations made for the effects of water in cooling the inlet air of aircraft-engine cylinders. From Summary: "The estimates indicate that the cooling effect of the water on the inlet air can be more extensive than the cooling now obtained with the intercoolers or aftercoolers in the air-induction system. In connection with water recovery from the exhaust gas, the estimates indicate that sufficient water can be recovered from 50 percent of the exhaust gas to provide an inducted water-fuel ratio of 0.5."

"Tests were run on a single-cylinder, air-cooled engine with a Wright C9GC cylinder to determine the improvement in cylinder-head cooling that can be obtained by building into the exhaust passage an insulating shield designed to protect the valve-guide boss and the exhaust-passage walls from the exhaust gas. The test results showed an appreciable improvement in cooling of the exhaust-valve-guide boss, of the guide bushing, and of the valve seat" (p. 1).

Report discusses a method of replica creation and testing of the surface-finish variation of aircraft engine parts subject to wear. In this report, a positive replica is created, the surface is treated, the replica is tested to make sure the fidelity is high enough, and a series of ring-sticking tests are conducted on the replicas. A summary of the results of the testing is also included.

Report describes the installation of six-cylinder blocks from two in-line aircraft engines on CUE crankcases, which permits the separate operation of any cylinder as part of a single-cylinder test engine. Using multicylinder-engine blocks for single-cylinder tests is advantageous because there is greater availability of standard engine parts and there is less temperature gradient. Modifications of the crankcase, camshaft-drive mechanism, and operation of the cylinder are described.

Report discussing the effect of inlet-air temperature and cylinder displacement on the charge temperature of an internal-combustion engine at the end of the induction stroke. The experiment to test various types of cylinders and their results on the air temperature and pressure is described.

Report discusses the results of testing water injection on a multicylinder aircraft engine and the potential fuel savings from the procedure. The speeds at which water injection for engine cooling is beneficial are illustrated and information about the manifold pressures and average rear spark-plug-gasket temperatures are also included.

Report discusses the results of an investigation to compare the discharge characteristics of an alcohol feed ring and a standard alcohol discharge nozzle when utilized to supply anti-icing alcohol to the propeller-blade feed shoes on a Curtiss-Wright C-46 cargo airplane. The equipment used, testing practices, and results of the alcohol flow distribution are described.

Report discusses the results of strength tests of several curved-sheet 24S-T aluminum alloy specimens stiffened longitudinally and transversely and loaded in shear. Curved-web beams and cylindrical shells were both examined in the tests. Results provided include the load at which the sheet began to show shear buckles, where the buckles occurred, and whether or not the failures involved rupture of the sheet.

"Two graphical methods are presented for determining the stick-free neutral point, and they are extensions of the methods commonly used to determine the stick-free neutral point. A mathematical formula for computing the stick-free neutral point is also given. These methods may be applied to determine approximately the increase in tail size necessary to shift the neutral point (stick fixed or free) to any desired location on an airplane having inadequate longitudinal stability" (p. 1).

Report discusses some unusual velocity-acceleration records on transport airplanes, which the report defines as "records of accelerations experienced in flight that resulted from causes other than atmospheric gusts" (from Summary). The analysis of the records, which is required for determining proper classification, is described, and the sorting of the records into gust- or maneuver-related is described. The report also discusses the importance of receiving this data from flight operators in addition to the routine information they provide.

Report discusses the results of testing of rudder deflection for trim at low speeds in the critical wave-off condition. Depending on the lateral center-of-gravity location on the airplane, the useful load in the wings will change and the ability of the rudder to trim the airplane may be greatly improved.

Report discusses the maximum lift coefficients for conventional and tailless airplanes in the gliding and landing conditions. Three areas are used to calculate the coefficients: wing area alone, wing area plus horizontal-tail area, and wing area plus horizontal- and vertical-tail areas.

Report discusses tests conducted using a model of a four-engine long-range flying boat with a 30 degree V-step and two different transverse steps of comparable positions and depths. The limits of stability, landing speed, and landing characteristics of the different models are presented.

Report discusses the results of compressive testing of 24S-T aluminum-alloy sheet-stiffener panels with five ratios of stiffener thickness to sheet thickness. For each ratio, rivets of five different diameters were used to attach the stiffeners to the sheets. The compressive strengths were found to increase with an increase in the diameter of the rivets until the ratio of rivet diameter to over-all thickness reached a certain point.