"The accuracy of the substitute-stringer approach for including the effects of shear lag in the calculation of the transverse modes and frequencies of multistringer box beams is investigated. Box beams, the covers of which consist of normal-stress-carrying stringers on sheets which carry not only shear but also normal stress, are analyzed exactly. Frequencies of beams with various numbers of stringers, obtained by means of this exact analysis, serve to determine the possible accuracy of the frequencies obtained by the substitute-stringer approach" (p. 1).

Report discussing a flight investigation of rocket-powered models of a tailless triangular-wing airplane configuration was made through the transonic and low supersonic speed range at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. An analysis of the aerodynamic coefficients, stability derivatives, and flying qualities based on the results obtained from the successful flight tests of three models is presented.

Report discussing an aerodynamic investigation of a slender pointed parabolic body of revolution was conducted at Mach number of 1.92 with and without the effects of an annular supersonic jet exhausting from the base.

From Summary: "This report describes a theoretical and experimental investigation of the aerodynamic mixing by a standing sound wave downstream from a continuous line source of heat."

From Summary: "A free-swiveling vane-type pickup for measuring air flow direction in both the angle-of-attack and angle-of-sideslip directions is described. Test results are presented which indicate that the pickup is aerodynamically stable and has an accuracy, obtained from a bench calibration, of better than 0.3^o under conditions including acceleration up to 20g in any direction, Mach numbers from 0.5 to 2.8, dynamic pressures up to at least 65 psi. Equations and curves which can be used to obtain flow direction at the center of gravity of a maneuvering model are presented."

From Introduction: "The time-averaged flows are considerably simpler to deal with theoretically than are the instantaneous flows, and the results of several theoretical analyses are available (refs. 2 to 6, for example). Several previous experimental investigations (see ref. 7 for a bibliography) have provided some qualitative information on the subject by the use of smoke in flight and in wind tunnels. However, quantitative measurements (refs. 8 to 10) are extremely scarce and, in general, are inadequate either to define the nature of the flow or to check the accuracy of the theoretical calculations."

From Introduction: "In this paper are presented descriptions of the camera setups and associated equipment, the equations and methods used in determining the model attitudes and motions from the film, and time-history curves of the variables of the spin and recovery investigated. Discussions of the nature of the spin and recovery obtained and of factors ostensibly affecting these motions are included."

"Time-history data of airspeed, altitude, and acceleration obtained with the NACA VGH recorder from a twin-engine airplane operated by a regional feeder airline in the Rocky Mountains are evaluated to determine the magnitude and frequency of occurrence of gusts and gust accelerations and the operating airspeeds and altitudes. The results obtained are compared with the results previously obtained from a representative short-haul and long-haul operation" (p. 1).

From Introduction: "The buzz or pulsation of axially symmetric supersonic inlets having central bodies has been the subject of investigations since Oswatitsch first observed the phenomenon in 1944 (ref.1). This buzzing is essentially an oscillation of the normal shock along the spike of certain diffusers operating at mass flows below design, and this buzz decreases the performance of the propulsion units appreciably (ref.2). This paper continues the analysis of the buzzing cycle by means of a modified one-dimensional approach."

From Introduction: "The object of the present paper is to present an approximate method for calculating accurately the thermal stresses in a thin plate with both chordwise and spanwise variations in temperature and chordwise but restricted spanwise variations in thickness."

From Introduction: "The purpose of the present paper is to present summary of the information gleaned from various transonic-bump investigations of wing and wing-fuselage configurations at two representative tail heights and to compare these results with theoretical estimations made in subsonic and supersonic Mach number range."

From Introduction: "Experimental results for flow in a rectangular channel with injection through a porous wall are given in reference 1. As part of the study to guide future experiments, laminar flow in a semiporous channel is investigated herein. In the present investigation, a third-order perturbation solution for laminar incompressible flow in a semiporous channel is presented."

From Introduction: "Results obtained in the experimental investigations of secondary flows in turbomachines (refs. 1 to 3) indicate that information concerning three-dimensional laminar boundary-layer behavior can be of practical value in interpreting and correlating measurements of losses in the turbo-machines for design purposes. Reference 4 gives a theoretical analysis of the overturning (more than mainstream turning) of the three-dimensional laminar boundary layer developed on flat or nearly flat surfaces, under mainstream flows which consist of streamline translates (i.e., the entire streamline pattern can be obtained by translating any particular streamline pattern can be obtained by translating any particular streamline parallel to the leading edge, fig. 1) with constant axial velocity component."

From Introduction: "The results are presented in the form of a structural-efficiency chart where minimum structural weight is plotted as a function of the structural index for constant values of the ratio of wing depth to skin thickness."

Report presenting an investigation at speeds of up to Mach number 0.90 to determine the effects of operating propellers on the longitudinal characteristics of a four-engine tractor airplane configuration with a 40 degree swept wing with an aspect ratio of 10. Results regarding low-speed conditions, high-speed conditions, components of lift, effect of configuration changes, longitudinal stability, and the reduction of adverse effects of propellers on stability are provided.

Report presenting a method for the analytical determination of the natural coupled frequencies and mode shapes of vibrations in the vertical plane of tandem helicopters. That information is then used to calculate the response of the helicopter to applied oscillation forces. Calculated response curves show how the vibrations of the cockpit vary with frequency and method of application of oscillating forces applied at the hubs.

From Introduction: "This study was the basis for the present paper which deals with means for compensating the roll and yaw response to side gusts of a fighter airplane in combination with an autopilot. Results are presented which compare the response to side gusts of the original and compensating autopilots; the responses to commands are presented also."

"An analysis shows that the scattering of unpolarized plane light waves which penetrate turbulent, transparent gases provides a measure of the average integral scale and intensity of the turbulent density fluctuations. The analysis is based upon the scattering coefficient deduced by Booker and Gordon and, thus, assumes isotropic fluctuations having an exponentially decaying (Markoffian) correlation function. Photometric data taken through turbulent boundary layers in air are found to conform functionally with the analytical prediction" (p. 1).

Report presenting the unsteady-lift functions for a wing undergoing a sudden change in sinking speed for delta wings with three aspect ratios and rectangular and elliptical wings with three aspect ratios. Results regarding the delta-plan-form K1 function, indical spanwise loading distributions, effect of plan-form shape on the K1 function, and effect of aspect ratio on the K1 and K2 functions are provided.

"A method is presented for obtaining the attenuation of a shock wave in a shock tube due to the unsteady boundary layer along the shock-tube walls. It is assumed that the boundary layer is thin relative to the tube diameter and induces one-dimensional longitudinal pressure waves whose strength is proportional to the vertical velocity at the edge of the boundary layer. The contributions of the various regions in a shock tube to shock attenuation are indicated" (p. 1).

Note presenting a determination of the time-average characteristics of boundary layers over a flat plate in nearly quasi-steady flow. The time averages were found without specifying the plate velocity explicitly except that it is positive and has an average value. Some remarks on the heat-transfer problem are also provided.

Note presenting a description of a new class of frequency-selective shock absorbers called band-pass shock absorbers, which were conceived as a means of overcoming some of the limitations of conventional shock absorbers. The shock absorbers may be designed to isolate two bodies from each other over certain ranges of exciting frequencies or rates of load application while coupling them over the remainder of the frequency spectrum.

Twenty-five ring-stiffened circular cylinders were loaded to failure in bending. The results are presented in the form of design curves which are applicable to cylinders with heavy rings that fail as a result of local buckling.

Report presenting calculations of approximate shapes of nonlifting bodies having minimum pressure foredrag at higher supersonic airspeeds. The investigation is carried out for various combinations of the conditions of given body length, base diameter, surface area, and volume.