Note presenting pressure measurements on the surface of a two-dimensional symmetrical double-wedge airfoil obtained from tests in the Langley 4- by 19-inch semiopen tunnel at lifting conditions and Mach numbers up to 1. The purpose of the investigation was to obtain normal-force, pressure-drag, and pitching-moment data and to compare them with available experimental and theoretical results.

"The aerodynamic stability derivatives due to pitching velocity and vertical acceleration are derived for circular cones traveling at supersonic speeds. Both first-order and a combination of first and second order potential solutions are obtained, and in calculations for the forces, no approximations are made to the tangency condition or the isentropic pressure relation. In addition, expressions for the forces, moments, and stability derivatives of arbitrary bodies of revolution are derived from Newtonian impact theory" (p. 1).

Report presenting the use of x-ray diffraction methods to identify the minor phases present in 20 high-temperature alloys in current use. The minor phases were noted in seven of the 20 alloys. A description of the relation of the alloys to one another and their chemical properties are provided.

Report presenting the effects of approximately 50-percent biaxial stretch-forming on the tensile and crazing properties of polymethyl methacrylate. Results indicated that biaxially stretch-forming polymethyl methacrylate approximately 50 percent does not affect its tensile strength of secant modulus of elasticity in tension. Results regarding standard tensile tests, stress-solvent crazing tests, long-time tensile tests, discussion of mechanism of crazing, accelerated weathering tests, additional experimental work, and possible applications of stretch-forming are provided.

Report presenting values of the nondimensional normal component of induced velocity throughout the flow field of a uniformly loaded lifting rotor operating in the upper half of the helicopter speed range in the form of graphs and tables. The results obtained should be useful for estimating the induced velocity distribution about lifting rotors in general and for synthesizing the distributions over the rotor disk for the case of any specified non-uniform loading.

Note presenting the application of the Laplace transformation to the solution of the lateral and longitudinal stability equations. The expressions for the time history of the motion in response to a sinusoidal control motion are derived for the general case in which all initial measurements are assumed different from zero.

Report presenting tests of a group of related NACA airfoil sections varying in maximum thickness, design lift coefficient, and thickness distribution in a two-dimensional open-throat wind tunnel at a range of Mach numbers. Normal-force, drag, and pitching-moment coefficients are presented with representative schileren photographs and pressure-distribution diagrams.

Note presenting a verification of previously derived equations for calculating the rate of heat transfer from airfoils in icing conditions, which have come about as a result of an investigation of the meteorological conditions conducive to the formation of ice on aircraft and a study of the process of airfoil thermal ice prevention. The results indicated that knowledge of these components has increased to a point where the design of heated wings on a fundamental, wet-air basis can now be undertaken with reasonable certainty.

Report presenting a theoretical study of the response to gusts and stability and control characteristics of an airplane equipped with systems in which wing flaps and elevators are operated to reduce accelerations in rough air. The surfaces are actuated by an automatic control system in response to indications of an angle-of-attack vane or accelerometer.

Note presenting extensive data relating properties of wrought N-155 alloy under static, combined static and dynamic, and completed reversed dynamic stress conditions. Time periods for fracture ranged from 50 to 500 hours at room temperatrue, 1000, 1200, 1350, and 1500 degrees Fahrenheit. Results regarding the rupture and fatigue strengths, fatigue strengths based on cycles to failure, influence of superimposed fatigue loads on creep, influence on superimposed fatigue stress on elongation in the rupture test, stress-strain characteristics under fatigue loading, damping effects, influence of cyclic speed on fatigue properties, influence of notches on fatigue, surface finish, and limitations of findings are provided.

Report presenting a combination of two previously published reports with an extension of the data to cover properties of fuels up to temperatures as high as 400 degrees Fahrenheit.

Report presenting a compilation of most of the zero-lift drag obtained from free-flight measurements on fin-stabilized bodies of revolution. Results regarding friction drag, base pressure and base drag, pressures on a forward facing step, and fin pressure drag are provided.