Report presenting exact and approximate methods based on linearized supersonic flow theory for the calculation of the velocity potential and the downwash from thin wings of arbitrary plan form. The applicability of the method inherently depends on a knowledge of the load distribution over the plan form of the wing.

Note presenting equations derived for the prediction of velocity distributions for fully developed adiabtic turbulent flow in smooth tubes; both the incompressible and compressible flow cases were treated. The analysis produced a single equation that represents flow in both the conventional buffer layer and the laminar layer. The results for fully developed flow were correlated by using conventional dimensionless velocity and distance parameters, and agreed closely with those of Nikuradse and other investigators.

"A study is made of the effect of variation in diameter and pitch of A17S-T4 aluminum-alloy flat-head rivets on the average stress at maximum load for 24S-T3 and 75S-T6 aluminum-alloy, flat, Z-stiffened panels that fail by local instability. A curve is presented for determining the diameter and pitch required to insure the development of a given average stress for local instability" (p. 1).

Note presenting a landing investigation to obtain quantitative measurements of the distribution of water pressure during landings, which can serve as an aid in the establishment of seaplane design criteria and in determining the value of the existing hydrodynamic pressure theories. Initial impact conditions and maximum pressures are presented for all landings together with time histories of the velocities and pressure distributions for several representative landings.

Note presenting an investigation of the design requirements and heat-transfer characteristics of exposed-wire instruments to be used for steady-state measurements at transonic and supersonic speeds. Design criterions, construction details, and typical response behavior are presented.

Note presenting a method of investigating hypersonic aerodynamic phenomena by firing simple symmetrical models at high velocity through a very cold gas with a low sonic velocity. Schileren photographs and focused shadowgraphs were taken of cylindrical models with conical forebodies with apex angles of 30, 45, and 60 degrees.

Report presenting an experimental investigation of 75-millimeter-bore roller bearings of three different cage types were conducted over a range of DN values and static radial loads with circulatory oil feed. Three incipient failures were noted out of seven bearings investigated. Results regarding rig bearing temperatures, bearing failures, effect of running time, circumferential temperature distribution, effect of DN value on operating temperature, effect of load on operating temperature, effect of circumferential temperature distribution, and effect of differential expansion upon running clearance are provided.

Report presenting the lateral motions of aircraft by means of the Laplace transform, which gives solutions expressed in terms of elementary functions for the free and forced motions.

From Summary: "Aerodynamic influence coefficients for symmetrically loaded wings of arbitrary plan form in subsonic flow are derived from a simple empirical method of estimating spanwise lift distributions. The application of the coefficients to an aeroelastic analysis is discussed."

Note presenting a method of calculating two-dimensional compressible flows past thin airfoils with particular reference to the transonic speed range. The method is based on the integral form of the equation of continuity and on the intrinsic form, in terms of the streamline curvature, of the irrotationality condition.

Report presenting a method that has been developed for the calculation of the natural coupled or uncoupled frequencies and modes of a structure with modifications directly from the known modes and frequencies of the unmodified structure. The method is advantageous when the modes and frequencies of the unmodified structure either are known or are required along with the modes and frequencies of the structure with various modifications.

Note presenting the results of spin-tunnel investigations compared with corresponding full-scale results for 60 different airplane designs. The purpose of the comparison was to determine the reliability of the model results in predicting full-scale spin and recovery characteristics. Results regarding the recovery characteristics, angle of attack, rate of rotation, altitude loss per revolution, angle of wing tilt, and emergency spin-recovery parachutes are provided.

"In a round turbulent jet at room temperature, measurement of the shear correlation coefficient as a function of frequency (through bandpass filters) has given a rather direct verification of Kolmogoroff's local-isotropy hypothesis. One-dimensional power spectrums of velocity and temperature fluctuations, measured in unheated and heated jets, respectively, have been contrasted. Under the same conditions, the two corresponding transverse correlation functions have been measured and compared" (p. 1).

Note presenting an investigation of the laminar boundary layer on a cooled 20 degree cone at Mach numbers of 1.5 and 2.0 to determine the variation of the position of transition with surface temperature for both constant surface temperatures and surface temperatures that increased toward the rear of the cone. The increase in the extent of the laminar boundary layer for uniform surface temperatures was found to be directly proportional to the difference between the surface and recovery temperatures.

From Introduction: "The primary purpose of the investigation described in the present report is to formulate a method which is of value for quantitative calculations of base pressure on airfoils and bodies without boat-tailing. Part I consists of a detailed study of the base pressure in two-dimensional and axially-symmetric inviscid flow. In part II a semi-empirical theory is formulated since the results of part I indicate that an inviscid-flow theory cannot possibly be satisfactory for quantitative calculations of a viscous flow."

From Summary: "A description is given of a linear-theory method for the estimation of the damping in roll of supersonic-leading-edge wings mounted on cylindrical bodies. The error resulting from an approximation essential to the method is shown to be small. The damping in roll is calculated for configurations having rectangular and triangular wings; for most of the range of variables the net effect of the body is to decrease the damping in roll."

Note presenting an experimental determination of the distribution of shear stress in a plane parallel to and a short distance from the fastening between the outer and intermediate laminations on a wing and of the effect upon the distribution of change the length and width of the specimen.

Report presenting theoretical results for the lateral force and yawing moment due to combined angle of attack and roll. The thin wings are tapered and have leading and trailing edges which are each swept at a constant angle; the tips are parallel to the center section.

"The results of an investigation of several internal water-inertia-separation inlets consisting of a main duct and an alternate duct designed to prevent automatically the entrance of large quantities of water into a turbojet engine in icing conditions are presented. Total-pressure losses and icing characteristics for a direct-ram inlet and the inertia-separation inlets are compared at similar aerodynamic and simulated icing conditions. Complete ice protection for inlet guide vanes could not be achieved with the inertia-separation inlets investigated" (p. 1).

"The effect of modifying the gas passage of hollow metal airfoils by the addition of internal fins and partitions was experimentally investigated and comparisons were made among a basic unfinned airfoil section and two airfoil designs having metal fins attached at the leading edge of the internal gas passage. An analysis considering the effects of heat conduction in the airfoil metal was made to determine the internal modification effectiveness that may be obtained in gas-heated components, such as turbojet-inlet guide vanes, support struts, hollow propeller blades, and thin wings" (p. 1).

"A photomicrographic technique for investigating seupercooled water droplets has been devised and. used. to determine the spontaneous freezing temperatures of seupercooled water droplets of the size ordinarily found. in the atmosphere. The freezing temperatures of 4527 droplets ranging from 8.75 to 1000 microns in diameter supported on a platinum surface and 571 droplets supported on copper were obtained. The average spontaneous freezing temperature decreased with decrease in the size of the droplets" (p. 1).

Report presenting an investigation to experimentally determine the effectiveness of air cooling several turbine-blade configurations in a turbojet engine. The results obtained with the first configuration, which was a hollow blade shell with 10 tube inserts, are presented. A description of factors leading to the design are provided as well as the correlated cooled-blade temperatures, solid-blade temperatures, cooling-air-temperature increase through radial passages, and blade failure are provided.

From Introduction: "V-g records supplied the NACA by the Bureau of Aeronautics in 1948 and 1949 have provided additional material. These records are analyzed statistically in this report to the frequency of large values of acceleration and airspeed, and results are compared with the design requirements."

From Introduction: "A comparison is also made of the actual performance of two contemporary jet engines with estimated performance, assuming the engines were equipped with adjustable-angle stators and adjustable exhaust nozzles. Charts are presented that aid in estimating the performance of adjustable-stator turbines."