This report is on the changes in forces on each wing of a biplane cellule when either the stagger or the gap is varied. Since each test was carried up to a 90 degree angle of attack, the results may be used in the study of stalled flight and of spinning as well as in the structural design of biplane wings.

The results of tests to determine the effect of wheel brakes on the landing run of an airplane under conditions of load and at various wind velocities are presented.

"This investigation on the relative wear of several bearing materials lubricated by gasoline was conducted at the Langley Memorial Aeronautical Laboratory, as part of a general research on fuel injection engines for aircraft. The specific purpose of the work was to find a durable bearing material for gear pumps to be used for the delivery of gasoline and diesel engine fuel oil at moderate pressures to the high pressure pumps of fuel injection engines" (p. 1).

This note describes tests of the drag due to a Wright "Whirlwind" (J-5) radial air-cooled engine mounted on a cabin type airplane. The tests were made in the 20-foot Propeller Research Tunnel of the National Advisory Committee for Aeronautics. The drag was obtained with three different types of exhaust stacks: Short individual stacks, a circular cross section collector ring, and a streamline cross section collector ring.

"The various speeds of an airplane can only be measured in horizontal flight, since there are no means for measuring the angle of ascent or descent. The measurements must be corrected for the density of the air. This is obtained by simultaneous pressure and temperature measurements during flight" (p. 1).

A review of various methods to prevent ice formation and adhesion to aircraft surfaces is given. It was concluded that the adhesion of ice to a surface may be reduced somewhat by the application of certain waxes and varnishes. In the experiments described, the varnishes containing calcium stearate and calcium oleate gave the best results. In wind tunnel tests, the adhesion was further reduced by the application of these waxes and varnishes to a thin, heat insulating layer of rubber.

Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.

Report presenting exact and approximate methods based on linearized supersonic flow theory for the calculation of the velocity potential and the downwash from thin wings of arbitrary plan form. The applicability of the method inherently depends on a knowledge of the load distribution over the plan form of the wing.

Note presenting equations derived for the prediction of velocity distributions for fully developed adiabtic turbulent flow in smooth tubes; both the incompressible and compressible flow cases were treated. The analysis produced a single equation that represents flow in both the conventional buffer layer and the laminar layer. The results for fully developed flow were correlated by using conventional dimensionless velocity and distance parameters, and agreed closely with those of Nikuradse and other investigators.

"A study is made of the effect of variation in diameter and pitch of A17S-T4 aluminum-alloy flat-head rivets on the average stress at maximum load for 24S-T3 and 75S-T6 aluminum-alloy, flat, Z-stiffened panels that fail by local instability. A curve is presented for determining the diameter and pitch required to insure the development of a given average stress for local instability" (p. 1).

Report presenting some simple approximate solutions that are derived for the relationships between rotor thrust and flight path velocity components and the rotor blade angle, torque, and in-plane forces.

Report presenting generalized expressions in closed form obtained for the characteristics due to control-surface deflection and wing angle of attack for wing plan forms with triangular-tip control surfaces at supersonic speeds. Charts are presented for the deflection characteristics for configurations having the sweep of the wing and control-surface trailing edges equal and for the location of the hinge line for balanced controls.

"A theoretical solution is obtained for the problem of the shear buckling of infinitely long simply supported elastic Metalite type sandwich plates. An approximate correction is suggested for the determination of the critical shear stresses of plates that buckle in the plastic range" (p. 1).

Report presenting an investigation of seven hot-pressed ceramics for possible gas-turbine application. The properties, short-time tensile strength, thermal-shock resistance, coefficient of liner expansion, and density were determined. The ceramics tested were magnesium oxide, titanium carbide, zirconium carbide, boron carbide, silicon carbide with boron carbide, zircon, and zirconia with lime.

Note presenting an approximate method developed to predict the location of detached shock waves ahead of two-dimensional and axially symmetric bodies. The method is based on the continuity relation, which is applied to the air that passes the sonic line.

Report presenting testing of five NACA airfoil sections intended for use in rotor blades in the two-dimensional low-turbulence tunnel. The airfoils varied in thickness and theoretical design lit coefficients. Results regarding pitching moment, lift, drag, and helicopter performance calculations are provided.

Note presenting experimental pressure-time measurements along with schileren photographs of the unsteady-flow phenomena initiated in constant-cross-sectional-area passages. The methods of calculation of the flow phenomena are based on the assumptions of one-dimensional, nonviscous, unsteady flow.

Report presenting the development of a rapid approximate method of analysis for both compressible and incompressible, nonviscous flow through radial- or mixed-flow centrifugal compressors with arbitrary hub and shroud contours and arbitrary blade shape. The method is used with eight numerical examples for two-dimensional flow, covering a wide range of flow rate, impeller-tip speed, number of blades, and blade curvature.

Report presenting an investigation of the aerodynamic coefficients of various bodies located in a free-molecule-flow field. The bodies include a flat plate, a cylinder, a sphere, and a cone.

Report presenting a flight investigation on a twin-engine transport airplane to determine the strains associated with the dynamic behavior of the wing during flights through rough air. Flights were made in clear-air turbulence for different wing fuel loads and for two speed conditions at a range of altitudes. Results indicated that the bending strains per unit normal acceleration in gusts were approximately 20 percent higher than those in slow pull-ups for all measuring positions and flight conditions of the tests.

Report presenting a theoretical analysis of the characteristics of constant-chord partial-span control surfaces on thin triangular wings at supersonic speeds by use of methods based on the linearized theory for supersonic flow. Two cases were treated with the analysis. Results regarding lift coefficient, rolling-moment coefficient, and hinge-moment coefficient due to flap deflection, hinge-moment coefficient due to angle of attack, and the pitching-moment coefficient due to flap lift.

From Introduction: "In an incomprehensible medium, the mutual interference of a fuselage and wing of high-aspect ratio (to which lifting-line theory is applicable) has been treated by Lennertz, Wiselsberger, Pepper, and Multhopp in reference 1, 2, 3, and 4. It is the purpose of this note to treat the effect of on the aerodynamic loading of the mutual interference between a low-aspect-ratio pointed wing and a fuselage consisting of a slender body of revolution."

Note presenting testing of an autopilot sensitive to yawing acceleration, which was used to control four simulated airplane (mass-spring) configurations, and a series of bench tests to determine the response characteristics of the combinations.

Report presenting a prediction of the magnitude of temperature variation in order to detect the places of highest temperature and to determine the operating temperatures admissible for the material of which the heat exchanger is composed. Results regarding the temperature distribution in triangular passages, temperature distribution in rectangular passages, influence of velocity field on temperature field, and a comparison of Prandtl number 1 solution are provided.