Note presenting an analysis and comparison of atmospheric turbulence as experienced by rocket-powered models and temperature lapse-rate data obtained from rawinsonde soundings in 38 cases by using an assumed temperature lapse-rate stability boundary as a basis for comparison. A limited correlation has been obtained which indicates that atmospheric conditions classified as being unstable will generally be turbulent, but a marginal or stable classification does not necessarily indicate smooth air.

Report presenting a theoretical approach to determine the lateral frequency response of a fighter airplane to side gusts and rolling gusts at a Mach number of 0.7 and an altitude of 30,000 feet. Frequency response and power spectral density were determined with the controls fixed and in combination with three different basic types of attitude autopilots.

Note presenting pressure-distribution expressions and stability derivatives derived by use of linear theory for zero-end-plate triangular vertical tails with subsonic leading edges performing rolling, yawing, and constant-lateral-acceleration motions. Corresponding results for the sideslip motion, most of which have been previously reported, are also included.

Report presenting transient data from approximate step and sinusoidal disturbances of fuel flow on a turbojet engine operated at one constant simulated altitude and flight condition. Results regarding coefficients of differential equations, Fourier representation, frequency response, transient analysis, and a comparison of the various analytical methods are provided.

Note presenting the nondimensional lift derivative and the corresponding pitching-moment derivative resulting from constant vertical acceleration as evaluated for a family of thin sweptback tapered wings with streamwise tips traveling at supersonic speeds. The analysis is applicable at those speeds for which the wing leading and trailing edges are both supersonic, provided that the Mach lines from the wing apex intersect the trailing edge and that the Mach line from the leading edge of one tip does not intersect the remote half-wing.

Note presenting a flight investigation of a three-blade propeller in climb and at high speed to determine the effects of blade power loading. Increasing the blade power coefficient from 0.06 to 0.09 was found to increase the efficiency approximately 8 percent at an airplane Mach number of 0.7 and a propeller-tip Mach number of 1.13. In climb, an increase in power loading over the range of blade power coefficients investigated was shown to reduce efficiency, as a consequence of increased induced drag losses.

Report presenting an investigation of the methods of analyzing longitudinal frequency-response characteristics of aircraft. The methods considered are analysis of sinusoidal response, analysis of transient response to harmonic content through determination of the Fourier integral, and analysis of the transient through the use of least-squares solutions of the coefficients of an assume equation for the transient time or frequency response.

Note presenting tables of thermal properties of stream that have been prepared in an NBS-NACA series. They include, for real gas, the compressibility factor, the density, the specific heat at constant pressure, the enthalpy, the entropy, the free-energy function, the viscosity, and the thermal conductivity.

Report presenting a theoretical investigation of the contribution of horizontal tails to the lift and pitching moment due to angle of attack, a constant rate of pitch, and a constant vertical acceleration. Methods for calculating the flow fields behind wings with constant vertical acceleration are developed.

Report presenting an analysis of the time-dependent downwash behind a wing in a supersonic stream when the angle of attack varies linearly with time. The result is applied to the calculation of the contribution of the horizontal tail to the pitching moment and lift due to normal acceleration of the airplane. Results regarding downwash charts and some limitations on the results are provided.

Note presenting a method for determining the time-dependent flow over a rectangular wing moving with a supersonic forward speed and undergoing small vertical distortions expressible as polynominals involving spanwise and chordwise distances. The solution for the velocity potential is presented in a form analogous to that for steady supersonic flow with the familiar "reflected area" concept.

From Introduction: "The design of turbojet-engine control systems is intimately related to the dynamic characteristics of the engine and has advanced to the stage where theoretically correct control constants can be determined for fixed dynamic properties (references 1 and 2). The use of the thermodynamic equations presupposes that the engine processes are quansi-static. Such an assumption is shown to be valid for a turbojet engine in references 3 and 4.

Note presenting wind-tunnel calibrations of three types of angle-of-attack sensing devices - the pivoted vane, the differential pressure tube, and the null-seeking pressure tube. Flight data on the position errors for three sensor locations - ahead of the fuselage nose, ahead of the wing tip, and on the forebody of the fuselage - are also presented. Various methods for calibrating angle-of-attack installations in flight are briefly described.

Note presenting a summary of the effects of plan form and thickness on the lift and drag characteristics of wings at transonic speeds. The data were obtained in the high-speed 7- by 10-foot tunnel by the transonic-bump method over a range of Mach numbers. Results regarding lift, drag at zero lift, and drag due to lift are provided.

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 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 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.

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.