Report discussing the suitability of 42 aromatic amines as antiknock additives for aviation gasoline at low temperatures similar to the ones encountered in flight.

Report presenting a consideration of some problems related to longitudinal stability in power-on flight. The results indicated that the destabilizing effects of power are more pronounced when the horizontal tail is required to carry a down load to maintain flight equilibrium.

Report presenting an investigation of the flow downstream from a two-dimensional grid formed of parallel rods. The nature of the flow was determined primarily by means of total-head measurements. Preliminary tests were made in both the closed-duct and open, two-dimensional configurations, but it was found that the same phenomenon occurred in both cases.

Report presenting direct-reading tables and charts for determining the drag or thrust coefficients from wake-survey measurements in the subsonic speed range. Additionally, numerical examples are provided using information from the tables.

"Experimental results of tests made at the Langley Memorial Aeronautical Laboratory are presented to show how heat-transfer coefficients can be increased by a method utilizing the high rate of heat transfer known to exist on any heat-transfer surface in the region adjacent to the edge on which the cooling or heating fluid impinges. The results show that, for the same pressure drop, the average surface heat-transfer.coefficient can be increased 50 to 100 percent when a cooling surface having a length of four inches in the direction of fluid flow is cut to form twenty fins with a length of 0.2 inch in the direction of fluid flow and the fins are sharpened and staggered in the air stream" (p. 1).

Report presenting an investigation into the importance of stick force as a criterion of longitudinal stability with special reference to transient effects for maneuvers of short duration. The analysis showed that different combinations of elevator parameters which give the same stick force per unit acceleration in turns give widely different force variations during the entries into and recoveries from steady turns and during maneuvers of short duration such as abrupt pull-ups.

Testing of a dynamically similar model of an Army A-20A airplane to determine the best way to land the airplane in calm and rough water and to determine its probable ditching performance. Results regarding the effect of speed and attitude, effect of flap setting, effect of wind and seaway, effect of simulated damage, effect of sinking speed, effect of propellers, effect of gun blisters, and effect of weight are provided.

From Summary: "Interdependence of intercooler parameters and performance for a pursuit-type airplane using a 1675-horsepower engine is shown at altitudes of 25,000, 36,000, 47,000, and 60,000 feet by means of perspective drawings. Qualitatively, the drawings have general application. Intercooling between stages of supercharging at high altitudes results in no saving in the power to supercharge and cool the engine air."

Report presenting testing in the 8-foot high-speed wind tunnel to determine the effect on external drag and pressure distribution of air inlet openings on the stagnation point of a streamline body. The results showed that external drag of the body with suitably designed nose-inlet and tail-outlet openings over a wide range of rates of internal air flow was no higher than the drag of the streamline body. Specific results for the streamline body, nose-inlet openings, outlet openings, and inlet-outlet combinations are provided.

Report presenting pressure distribution testing of an NACA 66,2-216, a = 1.0 airfoil equipped with a blunt nose balance aileron and a sealed internal-balance aileron and of an NACA 23012 airfoil equipped with a Frise aileron and a blunt nose balance aileron in the stability tunnel. Results regarding the section pressure distribution and section loads and moments are provided.

Data taken from tests at constant speed to establish trim limits of stability, tests at accelerated speeds to determine stable limits of center of gravity shift, and tests at decelerated speeds to obtain landing characteristics of several model hull forms were used to establish hull design effect on longitudinal stability of porpoising. Results show a reduction of dead rise angle as being the only investigated factor reducing low trim limit. Various methods of reducing afterbody interference increased upper trim limit.

Report presenting a consideration of the possibility of using conducting rubber as the conductor in aircraft ignition cable. The effects of stretch, temperature, and continuous and impulsive currents on the resistance of several conducting-rubber test strips of the same position were determined. Two types of experimental conducting-rubber cable were tested.

Report presenting an investigation of the effects of 0.20-aileron-chord tabs on an NACA 66,2-216 airfoil equipped with a 0.20-airfoil-chord plain sealed aileron. Basic data are presented from which the effect of tabs can be calculated for specific cases. The data are sufficient for the solution of problems of fixed tabs with a differential linkage, as well as simple and spring-linked balancing tabs.

Report presenting a derivation to show that, if the air-fuel ratio at lean mixtures is plotted against the fuel-air ratio at rich mixtures for identical values of the knock-limited indicated mean effective pressure on each side of the minimum indicated-mean-effective-pressure point, a straight line should result.

Report discussing an investigation of 24 aromatic amines as antiknock additives in aircraft gasolines and their low-temperature solubility.

Report presenting charts for the calculation of the critical stress for local instability of columns with I-, Z-, channel-, and rectangular-tube sections. An experimental curve is included for use in taking into account the effect of stresses above the elastic range on 24S-T aluminum alloy elasticity.

Report presents tables of stiffness and carry-over factor for infinitely long flat plates subjected to a uniformly distributed longitudinal compressive load. The tables can be used to help solve problems in the stability of structures made out of plates under compression.

Report presenting an investigation of a long column continuous over three supports to determine its critical load when the center support was given varying amounts of initial displacement. During each test, the middle support was hinged so as to be free to move parallel to the column axis during buckling. The critical loads predicted from load-deflection readings were different for the upper and lower spans.

Report discusses an investigation into the behavior of a cantilever beam in transverse motion with a mass at its tip when the root is suddenly brought to rest. Equations for determining the stresses, deflections, and accelerations that arise in the beam are also provided. This testing can be applied to the shock created in an airplane when landing and the vibrations that result.

Report discussing testing on triptane, hot-acid octane, diisopropyl, neohexane, mixed xylenes, cumene, benzene, toluene, and methyl tert-butyl ether in several blends to determine their knock-limited performance data in F-3 and F-4 engines at standard operating conditions. All of the blending agents examined were found to be usable, with concentrations varying depending on various thermodynamic properties.

"Flight tests were conducted on the XP-41 airplane, equipped with a Pratt & Whitney R1830-19, 14-cylinder, air-cooled engine, to determine the increase in flight speed obtainable by the use of individual exhaust stacks directly rearwardly to obtain exhaust-gas thrust. Speed increases up to 13 miles per hour at 20,000 feet altitude were obtained using stacks having an exit area of 3.42 square inches for each cylinder. A slight increase in engine power and decrease in cylinder temperature at a given manifold pressure were obtained with the individual stacks as compared with a collector-ring installation" (p. 1).

Report presenting a determination of the effectiveness of a charged condenser for breaking oil foams and to obtain data on which to base the design of such a device for mounting at the oil-tank inlet of an airplane. Results regarding the condenser-plate area and arrangement, wet-plate design, condenser voltage, oil temperature, water in oil, and some safety considerations are provided.

Tests of 10-ft. diameter, eight-blade, single - and dual - rotating propellers were conducted in 20-ft propeller research tunnel. Propellers were mounted at front end of a streamline body in spinners that covered hubs and parts of shanks. Effect of a symmetrical wing mounted in slipstream was investigated. Blade-angle settings ranged from 20 Degrees to 65 Degrees. Results indicated that dual rotation resulted in gains of from 1 to 8 percent in efficiency over single rotation for eight-blade propellers, but presence of a wing reduced gain about one-half. Greater power absorption caused by dual rotation over flight range and higher efficiency or thrust for range of take-off and climb was indicated.

Principles of the cross method of moment distribution, which have previously been applied to the stability of structures composed of bars under axial load, are applied to the stability of structures composed of long plates under longitudinal load.