Note presenting experimental investigations of boundary-layer suction through slots as a means of increasing the extent of laminar flow on airfoil sections. The results show that, with the use of suitable slots, substantial increases in the extent of laminar flow can be achieved by boundary-layer control with only a small expenditure of power. Results regarding slot geometry and arrangement, suction slots in an unfavorable pressure gradient, suction slots in a favorable pressure gradient, and determinations of the relations controlling the distribution of suction slots are provided.

Report presenting an investigation of the two-dimensional aerodynamic characteristics of 15 NACA airfoils at four Reynolds numbers. The results indicate that the drag coefficient at the design lift coefficient and the maximum lift coefficient are the most important aerodynamic characteristics and are most affected by Reynolds number changes.

Report presenting an analysis of two matrix methods for calculating responses of linear systems for given forcing functions and indicial responses in order to find a method suitable for solving the inverse problem of calculating forcing functions from known responses. The results of both methods are compared with exact solutions for both the direct and the inverse problems.

From Summary: "The theory of plastic buckling, originally derived for individual plates, has been extended to apply to combinations of plates such as H- and Z-sections. The theory has been applied specifically to extruded H-sections of 75S-T6 aluminum alloy; the calculated buckling stresses agree satisfactorily with the stresses obtained experimentally."

Report presenting an experimental investigation of boundary-layer suction through slots as a means of increasing the extent of laminar flow on airfoil sections. Results regarding slot geometry and arrangement, suction slots in an unfavorable pressure gradients, suction slots in a favorable pressure gradient, and a determination of the relations controlling the distribution of suction slots are provided.

"A theoretical solution is given for the critical shear stress of a simply supported curved rectangular plate stiffened by a central stiffener offering no torsional restraint which lies in either the axial or circumferential direction. Results are obtained by means of the Galerkin method and are presented in the form of computed curves and tables" (p. 1).

From Summary: "The spanwise lift distributions of wings of low aspect ratio but of arbitrary plan form and angle-of-attack distribution have been analyzed by two well-established concepts: the virtual-mass concept and the Weissinger method. Both concepts have been found to yield the same simple integral expression for the spanwise lift distribution in terms of the spanwise angle-of-attack distribution. Tables and figures of lit distributions of low-aspect-ratio wings have been presented."

Report presenting information for the determination of the theoretical lift, damping-in-roll, and center-of-pressure characteristics for a group of plan forms at supersonic speeds. The information is presented in three forms: equations, figures presenting generalized curves, and figures presenting curves for representative groups of configurations. Several observations are made in regards to the effect of taper ratio, angle of sweep, and aspect ratio on the values of the derivatives.

Report presenting a strain-energy theory established for the calculation of the buckling load in pure bending of reinforced monocoque cylinders which have a symmetric cutout on the compression side and buckle according to general-instability patterns. The difference between this theory and other theories is the use of the axial wave length as an additional parameter whose value was determined from a minimum condition.

Note presenting the compressive buckling stress of outstanding flanges reinforced by bulbs, which was computed by the strain-energy method for flanges with 10 shapes and a range of lengths. The results were checked for some cases by computations based on a differential-equation method. The results were analyzed to determine which shape of flange gave the greatest support to the structure to which it was attached.

Report presenting an investigation of a model of the Kingfisher XAUM-2 flying torpedo to determine the pressure recoveries within the jet engine nacelle and to determine the effects of several changes in model configuration on the aerodynamic characteristics of the model. The effectiveness of elevons and tabs as control devices was also investigated.

Report presenting airspeed and altitude data for nonscheduled cargo operations of a Douglas DC-4 airplane between Seattle, Washington and Alaska during February and March of 1947 to determine the probability of reaching or exceeding given values of airspeed and Mach number. The total probability of exceeding a placard never-exceed speed of 266 mph depends primarily on exceeding the speed in descent. The probability was found to be about once in 100 hours of descent or once in 1000 hours of general flying time.

Report presenting an investigation of a model of a tailless airplane in a high speed tunnel at a range of Mach numbers. Results are compared to those obtained from a sting-mounted model tested in the same tunnel and a semispan model tested with the wing-flow method. Information regarding basic aerodynamic characteristics, spoiler controls, lift characteristics, drag characteristics, pitching moment at zero lift, and stability and control is provided.

Report discussing tests of a scale model of the XB-51 airplane to determine its force, stability, and control characteristics in pitch and yaw at various Mach numbers. The effects of the dive breaks and the bomb bay are also described.

Report presenting a wind-tunnel investigation of a semispan delta wing with the leading-edge swept back 60 degrees. A half-delta control surface was used and testing was performed with and without fences. Results regarding the rolling effectiveness, wing characteristics, and control-surface characteristics are provided.

Memorandum presenting an analysis of selected experimental pressure-distribution data at transonic speeds for the purpose of deriving an empirical method which may be used for estimating the trailing-edge loads and bending moments at the design stage. The trailing-edge normal-force and bending-moment coefficients calculated by the derived method follow the general trend of the experimental data and appear to be a guide where specifically applicable chordwise pressure-distribution data at transonic speeds are not available.

Report presenting an investigation to determine the effects of a vertical tail with the leading edge swept back 63 degrees on the aerodynamic characteristics of a wing-fuselage combination with a wing with the leading edge swept back 63 degrees. The aerodynamic characteristics in sideslip with and without the vertical tail are also presented. Results regarding the directional stability, rudder effectiveness, and rudder hinge moments are described.

Report presenting an experimental study of the pressure fluctuations at the combustion-chamber inlets of a ramjet operating a Mach number of 1.92 in the supersonic tunnel. Results are presented for two burner configurations of different operating characteristics to indicate trends in pressure magnitude, frequency, and wave form. Results regarding the perforated conical flame holder, regenerative-type burner, and diffuser total-pressure recovery are provided.

Report discussing flow surveys made of several nozzles using two 2-dimensional steps at Mach number 6.98. Results regarding wall-pressure surveys, disturbance patterns in expansion, total-pressure survey, temperature recovery, and general nozzle characteristics are provided.

Report presenting rocket-powered flight tests from high subsonic to supersonic speeds and at high Reynolds numbers to determine the zero-lift drag of a transonic wing-body and body-alone configuration. The configuration tested featured a wing of 45 degree sweepback, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section, and a body of fineness ratio of 10 and a frontal area equal to 6.06 percent of the wing-plan-form area.

Report presenting an investigation to determine the aerodynamic characteristics in sideslip of a triangular wing of aspect ratio 2.04 in combination with a body of fineness ratio 12.5 and a vertical tail surface. The body combined with the triangular plan-form wing caused no significant changes in the lift characteristics of the wing and only a 1-percent decrease in the static margin. Results regarding the longitudinal characteristics, lateral and directional characteristics, and estimation of tail and rudder effectiveness are provided.

Report presenting a method for the preparation and purification of the intermetallic molybdenum desilicide was developed and its properties were determined. Chemical properties were found to be highly inert, unattacked by boiling hydrochloric acid, sulfuric acid, or aqueous sodium hydroxide, slightly attacked by nitric acid, and dissolved by molten sodium hydroxide. Other mechanical properties of the material were also provided.

Report presenting an investigation to determine the lift, drag, and pitching-moment characteristics of the NACA 0010 and 0010-64 airfoil sections at Mach numbers up to 0.91 and for a range of Reynolds numbers.

Report presenting an investigation to determine the possibility of delaying at moderate or large lift coefficients the onset of the abrupt supercritical drag rise of an airfoil section by the use of camber. Results indicated that the addition of camber to the NACA 0010 airfoil leads to significant improvements in the drag characteristics at moderately supercritical speeds .