From Summary: "Optimum proportions of tapered wings were investigated by a method that involved a comparison of wings designed to be aerodynamically equal. The conditions of aerodynamic equality were equality in stalling speed, in induced drag at a low speed, and in the total drag at cruising speed. After the wings were adjusted to aerodynamic equivalence, the weights of the wings were calculated as a convenient method of indicating the optimum wing. The aerodynamic characteristics were calculated from wing theory and test data for the airfoil sections. Various combinations of washout, camber increase in the airfoil sections from the center to the tips, and sharp leading edges at the center were used to bring about the desired equivalence of maximum lift and center-stalling characteristics. In the calculation of the weights of the wings, a simple type of spar structure was assumed that permitted an integration across the span to determine the web and the flange weights. The covering and the remaining weight were taken in proportion to the wing area. The total weights showed the wings with camber and washout to have the lowest weights and indicated the minimum for wings with a taper ratio between 1/2 and 1/3."

Three tapered airfoils based on the N.A.C.A. 2200, the N.A.C.A.-M6, and the Clark Y sections were tested in the variable-density wind tunnel at a Reynolds Number of approximately 3,100,000. The models, which were of aspect ratio 6, had constant core center sections and rounded tips, and tapered in thickness from 18 percent at the roots to 9 percent at the tips. The aerodynamic characteristics are given by the usual dimensionless coefficients plotted for both positive and negative angles of attack and by effective profile-drag coefficients plotted against lift coefficients.

Note presenting an investigation of three centrifugal impellers, the same except for angular blade curvature, to determine the effect of the distribution of blade loading on impeller performance. Results regarding impeller efficiency, energy addition and pressure ratio, flow characteristics, and operating range are provided.

From Introduction: "The results of varying only Reynolds number for several equivalent tip speeds are presented and probable reasons for the apparent variation of adiabatic efficiency with inlet temperature are discussed."

"Charts giving the compressive-buckling stress coefficients for sheet panels of a shape occurring in swept-wing plan forms are presented. The panels are assumed to be a part of a continuous flat sheet divided by nondeflecting supports into parallelogram-shaped areas. The stability analysis was performed by the energy method and the results show that, over a wide range of panel aspect ratio, such panels are decidedly more stable than equivalent rectangular panels of the same area" (p. 1).

"A correlation approach to the crippling-strength analysis of plate structures in new materials and at elevated temperatures is presented. Appropriately defined crippling-strength moduli and correlation procedures are given for predicting the effect of a change in material properties on the strength of a structure. The strength moduli are readily calculated from the effective compressive stress-strain curve for the structural material" (p. 1).

Report presenting a solution for the coupled and uncoupled modes and frequencies of wings (swept or unswept) mounted on a fuselage. Characteristic equations describing symmetrical and antisymmetrical modes of vibrations are created and applied to various types of wing vibration in numerical examples.

"An analytical investigation is made of the effect of shear lag on the bending vibration of wings that are designed essentially as shallow box beams, and a procedure is outlined for incorporating this effect in the determination of bending modes and frequencies. Numerical examples show that shear-lag action in a box beam can have a large influence on its vibration characteristics. The calculations indicate that even though only a small shear-lag action may be observed in a simple static deflection test of the beam, reductions in the second and higher-mode frequencies may be relatively large" (p. 1).

Report presenting a stability analysis of a long flat rectangular plate subjected to uniform longitudinal compressive stress and support along its longitudinal edges and one or more other longitudinal lines by elastic line supports. This was performed in order to provide more information about stabilization methods for thin-wing construction. The effective stiffness of different supports and the buckling observed in different structures is provided.

From Summary: "The results of a computational program are presented which give numerical values of the stiffnesses required of the various components of a multipost-stiffened wing to achieve desired buckling-stress values under bending loads. Two arrangements of the posts are considered, upright posts and posts used as diagonals of a Warren truss. This work extends and summarizes the calculations presented in NACA RM L52K10a."

Report presenting three experimental investigation conducted with 75-millimeter-bore cylindrical roller bearings to determine the effects of roller axial clearance ratio, cage diametral clearance ratio, and cage land width-diameter ratio on bearing operating temperatures, wear, cage slip, and high-speed operating characteristics.

Report presenting eleven 110-millimeter-bore ball thrust bearings made of M-1 tool steel were operated over a range of DN values at mean outer-race temperatures to 678 degrees Fahrenheit. Testing occurred at a variety of thrust loads, radial loads, oil flows, and oil inlet temperatures. Results regarding the difference between tests without heat addition and tests with heat addition, fatigue failures, performance of cage materials, and oil-interruption tests are provided.

Note presenting an investigation of the fatigue characteristics of riveted joints in aluminum alloy sheet. The purpose of this report is to summarize all the results of fatigue tests that have been made to date in the Aluminum Research Laboratories of lap joints with 1/8-inch aluminum alloy rivets.

Note presenting an investigation of the effects of tip dihedral on lateral stability and control characteristics by flight tests of models in the free-flight tunnel. The results indicate that at high lift coefficients, tip dihedral may cause a lightly damped lateral oscillation, which does not occur with full-span dihedral at similar values of effective dihedral and directional stability.

Report presenting an investigation to determine the performance of large tailless and conventional airplanes. The primary conclusion drawn fro the testing is that large all-wing tailless airplanes may have better performance characteristics than their equivalent tail-boom airplanes for certain types of missions. Results regarding a general performance comparison, performance variations with structural weight, landing speed, and take-off distance, and performance comparison based on arbitrary design specification are provided.

"This is a resume of the work of the Bureau of Standards on a cotton parachute cloth for use as a substitute for silk in the event of an emergency curtailing the supply. Cotton yarn of high strength in proportion to its weight and otherwise specially suitable for parachute cloth was developed. Cloth woven from this yarn in the bureau mill was equal or superior to parachute silk in strength and tear resistance, met the requirements with respect to air permeability, and weighed only a few tenths of an ounce per square yard more than the silk cloth" (p. 1).

Note presenting hot-wire anemometer measurements of the turbulent shearing stress in a turbulent boundary layer on a yawed flat plate. The measured velocity profiles are used to calculate the shear distribution and the result is compared with the result of experimental shear measurements.

Note presenting the problem of the effect of yaw on the turbulent boundary layer and skin friction of infinite cylinders, which is reviewed and compared with the case of laminar flow. The conclusion indicates that present understanding of the mechanism of turbulent shear does not permit exhaustion of two-dimensional data even to this elementary case of three-dimensional flow. Results regarding pressure distributions, two-dimensionality and flow direction, velocity profiles, virtual origin, virtual origin for yawed plates, boundary-layer growth, and the results obtained by Young and Booth are provided.

"A spoiler-type lateral-control system has been developed for use on the Northrop P-61 airplane. The lateral-control system is to be used with large-span flaps and consists of a thin circular arc spoiler, linked with a short-span plain aileron located just outboard of the spoiler. This unconventional lateral-control system has been accepted with enthusiasm by the pilots who have flown the airplane" (p. 1).

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.

Report presenting an evaluation of the flying qualities of the Douglas DC-3 airplane to determine its longitudinal and lateral stability and control characteristics and its stalling behavior.

"Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions" (p. 1).

Note presenting a description of an adiabatic specific-heat calorimeter bridging the interval between 4 and 15 degrees Kelvin temperatures. The instrument uses a constant-volume helium gas thermometer as the working thermometer. The instrument is tested on an alloy and a sample of pure titanium and the results are described.

Report presenting the two-dimensional aerodynamic characteristics of an NACA 64A010 airfoil with a slat at a range of Mach numbers. Two types of slat positions were investigated, one with the slat leading edge extended forward along the airfoil chord line and one with the slat extended forward and displaced below the chord line. Results regarding lift, drag, pitching moment, and pressure distribution are provided.