"Measurements of propeller efficiency loss due to ice formation are supplemented by an analysis to establish the magnitude of efficiency losses to be anticipated during flight in icing conditions. The measurements were made during flight in natural icing conditions; whereas the analysis consisted of an investigation of changes in blade-section aerodynamic characteristics caused by ice formation and the resulting propeller efficiency changes. Agreement in the order of magnitude of efficiency losses to be expected is obtained between measured and analytical results" (p. 1).

Memorandum presenting a procedure for obtaining qualitative information on the effectiveness of different slot configurations to make the flow of the cooling air visible. Two methods are utilized: one utilizes the traces caused by a reaction between paint spread over the blade surface and a gas mixed with the cooling air, while the other utilized smoke mixed with the cooling air to make it visible. From the visual observations, the use of a continuous slot as a means of creating the cooling film over the blade surface appeared to be superior to the use of holes or grooves.

Note presenting a method for calculating the pressure distribution and damping in steady pitch at supersonic Mach numbers of thin, flat, sweptback wings with all edges straight and subsonic. The two steps of the method are described and applied to wings with streamwise tips. The analysis showed that abrupt changes in pressure should occur along the various primary and reflected Mach lines on the wing, especially those originating at the tips of the leading edge.

Report presenting an investigation of the sintering process and sintering mechanism of a zirconium carbide-columbium ceramal. Results regarding the study of the bonding specimen and study of the sintering specimens are provided.

Report presenting a wind-tunnel investigation at low speed to determine the lateral control characteristics of an unswept untapered semispan wing of aspect ratio 3.13 equipped with 25-percent-chord plain unsealed ailerons with various spans and spanwise locations. Results regarding wing aerodynamic characteristics and aileron control characteristics are provided.

Report presenting a simplified method for the experimental determination of the moments of inertia, product of inertia, and inclination of the principal axes, the associated equipment and techniques, and the application of this method to a conventional airplane.

Report presenting an analysis of the performance of an axial-flow-type turbojet engine operating with shaft-power extraction by matching experimentally determined component characteristics of a typical axial-flow engine. General working charts are provided to investigate engine performance with variable and rated tail-pipe-nozzle area operation at constant turbine-inlet temperature, engine speed, and thrust.

Report presenting boundary-layer measurements in the transonic and supersonic regions of a channel with maximum cross-sectional dimensions 3.84 by 10 inches and designed by potential-flow methods for a uniform Mach number of 2.08. Results regarding the Mach number distribution along the channel, temperature recovery and Prandtl number, boundary layer development, skin-friction coefficient, and secondary flows are provided.

Report presenting an investigation in the gust tunnel of a 60 degree sweptback-wing model to determine the effect of a large angle of sweep on gust loads. A simplified method of analysis, which uses a slope of the lift curve derived by the cosine law and which uses strip theory to estimate the penetration effect, appears to be applicable to the prediction of gust loads on wings swept as much as 60 degrees.

Report presenting generalized expressions for closed form by means of linearized theory for the aerodynamic characteristics due to the deflection of inboard trailing-edge flaps. The analysis considers the effects of Mach number and flap aspect ratio, taper ratio, and sweep for conditions where Mach lines lie behind the flap leading and trailing edges. Design charts are presented for rapid estimation of the aerodynamic characteristics due to flap deflection.

From Introduction: "In the present report an analysis was undertaken to arrive at a mathematical formula by which the shear strengths of honeycomb core materials could be calculated. Experimental verification of the formula of the present paper was obtained by tests of honeycomb-type sheets of resin-impregated paper; two groups of specimens were tested, each of which represented a different resin-impregation treatment of the basic paper."

Note presenting the concept that when the temperature in the atmosphere increases linearly with height, the speed of propagation of long waves does not approach a limit with increasing wave length, as in the case of an atmosphere in which the temperature at great heights is assumed to be constant or decreasing, but increases linearly with the period.

Note presenting a summary of the interpretation of measured impact pressures in a rarefied gas. Experimental results are presented for source-shaped impact tubes for Mach numbers between 2.3 and 3.6 and Reynolds numbers from 25 to 804.

From Introduction: "The present paper introduces the approximate method by means of which it is possible to calculate the pressures in the tip region of a rectangular with a symmetrical circular-arc section to a higher degree of accuracy than is possible with the usual linear methods."

From Introduction: "The fundamental integral equation for the pressure distribution on an oscillating thin airfoil moving at subsonic speed has been derived by Possio in reference 1. Collocation procedures have been used by Possio, Frazer, and Skan, and others to obtain lift and moment on an oscillating first plate. An important contribution has been made by Dietze (see reference 2 and 3), who has developed an iterative procedure for numerical solution of Possio's integral equation."

Report presenting calculations and flight-test measurements on a single-main-rotor helicopter indicate that the damping moment about the helicopter center of gravity produced during pitching or rolling by a rotor which has flapping hinges on the rotor shaft, which depends primarily on four quantities: rotor speed, blade mass factor, height of the rotor hub above the helicopter center of gravity, and the ratio of collective pitch to the thrust coefficient - solidity ratio.

Report presenting an investigation of the use of the transonic similarity law for two-dimensional flow by an iteration procedure. The results indicated that potential can be expressed as a power series in a single parameter that depends on Mach number, thickness ratio, and ratio of specific heats.

Note presenting the computation of the effect of heat-capacity lag in the adiabatic expansion of a gas through a turbine nozzle computed using a one-dimensional analysis of a representative flow process. A number of parameter variations in the flow process are considered to determine the factors that amplify this effect and to show the magnitude of the deviation from equilibrium conditions.

Note presenting the development of a NACA oil-damped V-G recorder in which viscous damping of accelerometer results in improved frequency response, reduces susceptibility to vibration, and eliminates the necessity for field adjustments of damping.

Report presenting flight tests to determine the causes of undesirable dynamic lateral-stability characteristics of an airplane. Various rudder modifications were flight tested with the rudder free and fixed over an indicated airspeed range from approximately 200 to 450 miles per hour. Results regarding rudder-fixed characteristics and rudder-free characteristics are provided.

Report presenting an analysis of the effects of variable heat capacity on the flow parameters for oblique shock waves at high supersonic speeds at sea level. Two sets of data are provided: one for conditions immediately behind the shock wave at active degrees of freedom and another for asymptotic conditions behind the shock wave where all degrees of freedom are in equilibrium.

Report presenting an investigation to determine the effect of sweep, taper ratio, and aspect ratio on the aerodynamic characteristics of nine semispan wings with NACA 65A006 airfoil sections with and without split flaps. Lift, drag, pitching-moment, and wing-root bending-moment characteristics are presented for a range of Reynolds numbers.

Theoretical analysis of performance of a ducted-fan power plant designed both for high-output, high-altitude operation at low supersonic Mach numbers and for good fuel economy at lower fight speeds is presented. Performance of ducted fan is compared with performance (with and without tail-pipe burner) of two hypothetical turbojet engines. At maximum power, the ducted fan has propulsive thrust per unit of frontal area between thrusts obtained by turbojet engines with and without tail-pipe burners. At cruise, the ducted fan obtains lowest thrust specific fuel consumption. For equal maximum thrusts, the ducted fan obtains cruising flight duration and range appreciably greater than turbojet engines.

Ignition characteristics of AN-F-32 and two AN-F-58a fuels were studied in a single can-type turbojet combustor under air-flow conditions representing engine speeds of 1600, 2500, and 4000 rpm, altitudes from sea level to 30,000 feet, ambient temperatures at sea level from 90 degrees to minus 36 degrees F, and flight Mach numbers of 0 and 0.6. Critical fuel-flow rates for ignition increased with increase in preignition engine speed, with increase in altitude, or with decrease in sea-level ambient temperature. This flow rate appears to increase in a direct relation to decrease in fuel volatility as indicated by the 10-percent-evaporated temperature.