From Summary: "A statistical study is made of icing data reported from weather reconnaissance aircraft flown by Air Weather Service (USAF). The weather missions studied were flown at fixed flight levels of 500 millibars (18,000 ft) and 700 millibars (10,000 ft) over wide areas of the Pacific, Atlantic, and Arctic Oceans. This report is presented as part of a program conducted by the NACA to obtain extensive icing statistics relevant to aircraft design and operation. The thousands of in-flight observations recorded over a 2- to 4-year period provide reliable statistics on icing encounters for the specific areas, altitudes, and seasons included in the data."

Report presenting an investigation in the high-speed 7- by 10-foot tunnel to determine some effects of tail height and wing plan form on the static longitudinal stability characteristics of a complete, small-scale model at high subsonic speeds. It had both a low-tail and high-tail position. Results regarding the lift and drag characteristics and longitudinal stability characteristics are provided.

Report presenting a description of a new blade series designed to operate at near choking inlet Mach numbers and to have near maximum critical Mach numbers by employing high aerodynamic loading of the profiles in the leading-edge region. Results regarding aerodynamic characteristics and prediction of high-speed performance are provided.

From Summary: "Charts are developed for the analysis of flow in a whirling constant-diameter duct. These charts permit the determination of the duct-exit Mach number, or the Mach number at any point along the duct, for practical ranges of duct-inlet Mach number, duct-tip Mach number, friction factor, ratio of ambient temperature to duct-flow total temperature, ratio of duct-tip radius to duct hydraulic diameter, and heat conductivity through the duct wall and surrounding material. The method of using the charts is illustrated through the computation of a sample problem."

Report presenting calculations of the lift and moment responses to penetration of sharp-edged traveling gusts for wings in incompressible and supersonic two-dimensional flow, for wide delta and rectangular wings in supersonic flow, and for very narrow delta wings. The results of the calculations indicate that the forward speed of the gusts has a large effect on the lift- and moment-response functions.

Report presenting a study of the use of a magnetic field to control the motion of electrically conducting fluids. Results indicated that the skin friction and heat-transfer rate are reduced when the transverse magnetic field is fixed relative to the plate and increased when fixed relative to the fluid.

Note presenting an evaluation of the boundary layer along the walls of a shock tube, which induces pressure and velocity gradients within the core of potential flow.

Note presenting a study to determine if common aircraft metals produce friction sparks capable of igniting combustibles that might be spilled in an airplane crash. Samples of aluminum, titanium, magnesium, chrome-molybdenum steel, and stainless steel were dragged over concrete and asphalt runways while a combustible mixture of gasoline, JP-4 fuel, kerosene, or preheated oil was sprayed around the sample.

The manner in which the jet engine may start a crash fire was explored in test-stand and full-scale crash studies. On the basis of these studies, a method was devised for inserting and cooling the engine parts that may serve as ignition sources in crash. This method was tried successfully in full-scale crashes of jet-powered airplanes carrying engines in pod nacelles and engines buried within the airplane structure.

Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

Note presenting equations of motion derived for the dynamic response of an aircraft to random atmospheric gust loads. The equations include the degrees of freedom of plunging, pitching, rolling, and an arbitrary number of elastic normal modes. Results for simplified cases show that unsteady aerodynamic theory is not important for increasingly large values of the turbulence scale compared with values of the wing chord.

From Summary: "A variational theorem is presented for a body undergoing creep. Solutions to problems of creep bending and creep collapse of plates, columns, beams, and shells can be obtained by means of the direct methods of the calculus of variations in conjunction with the stated theorem. The application of the theorem is illustrated for plates and columns by the solution of two sample problems."

Note presenting experimental influence coefficients and vibration modes and frequencies of a built-up 45 degrees delta-wing specimen. The symmetrical and antisymmetrical static influence coefficients were obtained on a three-point support.

Report presenting a phenomenological relation between stress, strain rate, and temperature to account for the behavior of polycrystalline metals above the equicohesive temperature. This is because the behavior of metals at elevated temperatures is constantly becoming a more important problem. The validity of the relation suggested in the equation appears to be accurate for 7075-T6 aluminum alloy.

Vapor fuel-oxidant mixing is analyzed for standing transverse acoustic fields simulating those existing in screeching or screaming combustors. The additional mixing due to the acoustic field is shown to be a function of sound pressure and frequency, stream velocity, and turbulence. The effects of these parameters are shown graphically for a realistic range of combustor conditions. The fuel-oxidant ratio at various combustor stations is shown to have a cyclic fluctuation which is in phase with the pressure fluctuations. Possible mechanisms contributing to screech and scream are discussed.

Bluntness was more effective in displacing transition downstream on a cylinder than on a cone. The downstream displacement of transition is related to the formation of a shock layer within which the Reynolds and Mach numbers are reduced and to pressure gradients that exist over the forward part of the model. Round bluntness in general had a favorable effect, whereas sharp-cornered flat bluntness above a certain size had unfavorable effects on the location of the transition point.

Report presenting fatigue testing conducted on box beams and tension panels in order to study some of the factors affecting fatigue-crack propagation. Static testing was also performed on box beams, on tension panels, and on two types of wings, all of which contained fatigue cracks.

A Nusselt-Reynolds number relation for cylindrical thermocouple wires in crossflow was obtained from the experimental determination of time constants. Tests were conducted in exhaust gas over a temperature range of 2000 to 3400 R, a Mach number range of 0.3 to 0.8, and a static-pressure range from 2/3 to 1-1/3 atmospheres, yielding a Reynolds number range of 450 to 3000. The correlation obtained is Nu=(0.428 plus or minus 0.003) times the square root of Re* with average deviations of a single observation of 8.5 percent. This relation is the same as one previously reported for room-temperature conditions.

Report presenting a derivation of the lateral motions of an airplane flying through continuous random isotropic turbulence in terms of three different functions and sets of forces. Three airplanes of different size are used to demonstrate the method, illustrate characteristic trends, and exhibit some simplifications possible in the calculations.

A method is presented for the approximate solution of the nonlinear equations transonic flow theory. Solutions are found for two-dimensional flows at a Mach number of 1 and for purely subsonic and purely supersonic flows. Results are obtained in closed analytic form for a large and significant class of nonlifting airfoils. At a Mach number of 1 general expressions are given for the pressure distribution on an airfoil of specified geometry and for the shape of an airfoil having a prescribed pressure distribution. Extensive comparisons are made with available data, particularly for a Mach number of 1, and with existing solutions.

From Summary: "This paper briefly summaries the more important statistical data obtained by the NACA on the subject of ground loads. The information presented relates primarily to landing-impact and taxiing loads; however, some limited data are also presented on one phase of ground-handling loads, namely, braking friction. A number of experimental and theoretical papers dealing with various aspects of the subject are listed in the bibliography."

Note presenting tests of a hydraulic-power-controlled helicopter to determine the effect of friction in the servovalves and the effect of stick friction when the valve friction is present. The tests showed that, when the valve friction is equivalent to about 1 3/4 pounds of force at the stick, precision flying is difficult and more work is required of the pilot.

Two-dimensional tests were made of an NACA 0006 airfoil with area suction applied to a porous region on a 0.3-chord trailing-edge flap deflected 50 degrees. The lift with suction approached the value computed from thin-airfoil theory. The lift gains and suction quantity requirements were unaffected by the perforation patterns of the surface over a wide range of hole sizes and spacings.

Report presenting a theoretical investigation to study the effects of systematic changes in configuration of a representative airframe on the center-of-pressure travel due to changes in angle of attack and Mach number. The airframe was an unbanked canard missile configuration with low-aspect-ratio coplanar wing and tail surfaces of triangular plan form.