Note presenting the results of a survey of background and aircraft noise levels in residential communities in eight cities with major airports. The measurements were made in areas up to 12 miles away from the airports and were located in regularly used flight paths. The results indicated that there is a range of more than 20 decibels in the average background noise in the 180 areas included in the survey.

Note presenting the operating characteristics of an acceleration restrictor which limits the normal acceleration of an airplane in maneuvers determined from tests on a simulator. The simulator consisted of a control stick geared to a magnetic brake unit and an analog computer which simulated the dynamic characteristics of the airplane.

From Introduction: "These aerodynamic data were used previously in an analytical investigation of a spin recovery by rudder reversal, the results of which have been published in reference 2. Because of certain discrepancies in the rotary-balance data similar to those discussed in reference 3, some modifications were made to the aerodynamic data used in calculating the results in reference 2 and also the results in this paper; these discrepancies and modifications are discussed in detail herein."

Report presenting an approximate, theoretical analysis of the inlet or induction losses due to subsonic flow into a high-solidity cascade of finite thickness blades at incidence angle. Results indicated that the losses can become considerable for large deviations from the design incidence such as compressor off-design operating conditions. Results regarding the computational results, significance of assumptions and limitations, comparison of theoretical approximation with actual compressor results, and applicability of the results are provided.

Report presenting a theoretical and experimental investigation of heat transfer involving laminar natural convection of fluids enclosed between parallel walls oriented in the direction of body force. The results are presented in the form of equations for the velocity and temperature profiles and ratio of actual temperature drop across the fluid to the temperature drop for pure conduction.

Report presenting a systematic investigation of the sound field of a 1,000-pound-thrust solid-fuel rocket and data on two other rockets of 900 and 5500 pounds of thrust, which were obtained at a few isolated field points. Each of the three rockets was found to produce spectra somewhat similar to those of subsonic jets, which were random and with an envelope which peaks in the lower part of the audible range.

"The problem of increasing the range of supersonic aircraft by the use of twisted and cambered wings is considered, primarily for the purpose of developing a rational method for the selection of a design lift coefficient. Relations and curves are presented from which a suitable selection may be made, depending on the relative importance of maximum range and top speed" (p. 1).

Note presenting the use of the hot-wire anemometer as an instrument for experimental investigations of the transient flow phenomena in a shock tube. The response of a hot-wire to a transient step-function type of change in flow conditions is studied and a criterion for predicting the right compensation is theorized and experimentally verified.

Note presenting a general theory of the so-called equations of motion methods for the analysis of linear dynamical systems. When viewed from this general vantage point, all of the linear methods can be extended in a straightforward manner to apply to the analysis of nonlinear systems.

Note presenting a theoretical investigation made to determine the effects of an elastic wing on the dynamic longitudinal stability of thin-wing airplane configuration. In order to investigate the effects of various important parameters, the configurations were assumed to vary in wing sweep angle from 0 to 60 degrees, in center-of-gravity location from 25 percent mean aerodynamic chord to 45 percent mean aerodynamic chord, and in ratio of wing mass to airplane mass from 0.15 to 0.50.

Report presenting an investigation of the effectiveness of a wing equipped with large-chord plain flaps and auxiliary vanes in rotating the thrust vector of two large-diameter propellers through the large angles required for vertical take off and low-speed flight. The semispan model was equipped with a 60-percent-chord flap, a 30-percent-chord flap, and two large-diameter overlapping propellers. Results regarding static thrust conditions, tests with forward speed, and application of results are provided.

"Room-temperature stress-strain curves are presented for compression, tension, and shear loadings on four compositions of tungsten carbide with cobalt binder. Values of modulus of elasticity, modulus of rigidity, Poisson's ratio in the elastic region, ultimate strength, density, and hardness for the four materials are tabulated" (p. 1).

Report presenting temperatures on the external surface of a straight hollow cylinder aligned parallel to the air stream. Results regarding the recovery-factor distribution without roughness, transition without roughness, transition caused by roughness, and analysis of roughness results are provided.

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.

Note presenting structural theory and analogous electrical circuits developed for stiffened shells with flexible rings. The type of shell considered in the paper has an elongated shape and consists of a thin skin supported by stringers and rings. The means of analysis used in the paper is an electric analog computer of the direct analogy type.

From Summary: "The corrosion of 3S-0 and 52S-0 aluminum, AISI 347 and 321 stainless steels, 'A' nickel, and low-leaded brass has been determined from the weight change of specimens exposed alternately to liquid and gaseous fluorine. Experiments were continued for a total exposure time of up to 3.5 months. It was found that corrosion is negligible under the conditions of the experiment."

Report presenting a number of possible solid lubricants with various crystal structures tested in a low-speed, high-load, friction apparatus under conditions of continuous sliding. None of the solids tested were as effective as MoS2 but were at least as effective as zinc stearate and graphite in these tests. Results regarding common lubricants, layer-lattice structure, and low-shear-strength solids without layer-lattice structure are provided.

"An analysis based on mixing-length theory is presented which indicates that surface blowing associated with transpiration cooling systems produce large reductions in both the heat-transfer and skin-friction coefficients for a turbulent boundary layer on a flat plate. The numerical results are restricted to the case of air blowing into air. The effects of blowing are indicated to be similar for high-speed, compressible flow to those for low-speed, incompressible flow" (p. 1).

Note presenting a method for calculating supersonic potential flows in annular cascades of blades by the method of characteristics.

Report presenting some details of the physical mechanism of the combustion of magnesium ribbon and burning times for magnesium ribbons with various mixtures of oxygen in argon, nitrogen, helium, and argon-water vapor. Results regarding the types of gaseous reactions that occurred are also provided.

Note presenting a single-rotor helicopter and an airplane flown in formation in rough air for the purpose of measuring and comparing the responses of the aircraft to gusts. Rough-air flights were also made by the helicopter alone at several airspeeds over the same ground path. The results indicated a somewhat greater gust alleviation for the helicopter than for the airplane over the speed range investigated.

Report presenting a description of a two-degree-of-freedom system that forces rolling oscillations. Details of the system, the theory, and the method of operation are discussed. Results indicated that the quantities related to the primary mode of operation of the system could be obtained satisfactorily.

Note presenting a determination of the effect of a strong, negative pressure gradient on the local rate of heat transfer through a laminar boundary layer on the isothermal surface of an electrically heated, cylindrical body of revolution with a hemispherical nose from wind-tunnel tests at a Mach number of 1.97. Results regarding pressure distributions, temperature distributions and recovery factor, and heat transfer are provided.