Note presenting a method for analyzing extreme-value data which may arise in a wide variety of applications. Discussion of the method is preceded by the necessary statistical theory which also furnishes a basis for evaluating the new method in relation to existing ones. Several appendices are also included for mathematical developments not included in the text.

Report presenting information regarding lubricants of reduced flammability, including the determination of the change in spontaneous ignition temperature, stability testing, and a practical method for synthesizing them.

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 the static properties and resistance characteristics of a family of seaplane hulls with a variety of length-beam ratios. The hydrodynamic stability and rough-water behavior of the family of hulls has been reported on previously. Results regarding static properties, resistance characteristics, and take-off calculations are provided.

Report presenting testing on three circular-arc-fuselage and nine unswept-vertical-tail models in order to investigate interference effects between fuselages and vertical tails in sideslip. Report presenting effectiveness of isolated vertical tails, effectiveness of vertical tail plus mutual interference of fuselage and vertical tail, interference of fuselage on vertical tail, interference of vertical tail on the fuselage, longitudinal position of center of pressure of combined loading, vertical location of the center of pressure, and a comparison with some theoretical calculations are provided.

Note presenting the general dynamic equation of creep bending of a beam loaded laterally and axially as derived for a linearly viscoelastic material whose mechanical properties can be characterized by four parameters. The equation derived was used to obtain the creep bending deflection of a beam in pure bending and of a column with initial sinusoidal deviation from straightness.

Note presenting differential equations of bending of an idealized H-section beam column derived for a nonlinearly viscoelasic material whose mechanical properties are analogous to a model consisting of a linear spring in series with a nonlinear dashpot whose strain rate is proportional to a power of the applied stress. The resulting constant stress or load creep curve consists of a straight line, the slope of which can be considered as the secondary creep rate of a real material.

Report presenting formulas for the determination of the creep deflection-time characteristics of an initially curved idealized H-section column. The results were obtained from closed-form solutions of the differential equation of bending of a beam column with creep properties of a nonlinearly viscoelastic nature. Critical time is tabulated and plotted for a wide range of parameters involved.

Note presenting a theoretical investigation of the time-temperature-dependent buckling of a pin-jointed constant-section column, whose initial curvature is defined by a half-sine wave when the material is linearly viscoelastic and is heated uniformly along the column at a prescribed time rate.

"Measurements were made of the resistance to air flow of commercially available porous materials. Three general types of porous media were tested - granular (sintered materials), fibrous (felt cloths and filter papers), and perforated. The flow-resistance characteristics of the porous materials tested are presented in a form intended to assist in the selection of materials for applications to boundary-layer control using area suction" (p. 1).

Report presenting the calculation of aerodynamic loading on the fuselage by representing a midwing wing-fuselage combination with a fuselage of circular cross section with a simple system of horseshoe vortices located on the wing with images located inside the fuselage. Methods for calculating the downwash far behind the wing, the induced lift, and the spanwise lift distribution on the wing are provided.

"Theory and experiment were compared and found in good agreement for the elastic buckling under combined stresses of long flat plates with integral waffle-like stiffening in a variety of configurations. For such flat plates, 45 degree waffle stiffening was found to be the most effective of the configurations for the proportions considered over the widest range of combinations of compression and shear" (p. 1).

Report presenting a rapid and sufficiently accurate method of determining laminar-boundary-layer characteristics in flow with a given free-stream Mach number and given velocity distribution at the edge of the boundary layer. The method can be easily applied to flow with zero pressure gradient for any constant Prandtl number of the order of unity and any given temperature distribution along wall.

Note presenting a discussion of the use of the substitute-stringer approach for including shear lag in the calculation of transverse modes and frequencies of box beams. The ratios used for the configurations presented in the report bracket those which would occur in most actual box beams.

Report presenting an investigation of the correlations of pressure with itself and of pressure with two velocity components for the case of isotropic turbulence. The correlations are expressed in terms of correlations involving two velocity components at a point and two velocity components at another point.

Note presenting structural analyses made of two 45 degree swept wings of aspect ratio 3. One has a constant depth and the other had a constant biconvex cross section in planes parallel to the air stream. Deflections, all internal forces, and vibration modes have been calculated for concentrated static loads.

Report presenting testing of notched specimens made of 24S-T3 and 75S-T6 aluminum-alloy sheet material, with theoretical stress-concentration factors equal to 4.0, subjected to completely reversed axial loads. Test techniques and special test apparatus are described.

Report presenting an experimental and theoretical study of the instantaneously sharp and irregular front that is found to separate turbulent fluid from contiguous "nonturbulent" fluid at a free-stream boundary.

Report presenting a method for estimating variations in the roots of the lateral-stability quartic due to changes in mass and aerodynamic parameters of an airplane. The method is applied to three high-speed airplanes and the changes in their lateral stability characteristics are determined by considering increments in various airplane parameters.

Note presenting structural analyses made for four straight multicell wings. Wings with aspect ratios of 2 and 4 with rectangular and biconvex cross sections have been considered. The results indicated that under bending loads, all of the wings show fairly good agreement with beam theory.

Note presenting equations for the span load distribution resulting from constant vertical acceleration derived for a series of thin sweptback tapered wings with streamwise tips on the basis of the linearized supersonic-flow theory. The analysis is valid at Mach numbers for which the wing leading and trailing edges are supersonic.

Report presenting a fuselage-vertical-tail combination with tails of two aspect ratios, each of which was tested at four tail lengths, and oscillated in yaw through a range of reduced-frequency parameter corresponding to the lateral motions of airplanes. Three phase angles were measured with the tail in the presence of the fuselage.

Report presenting an experimental investigation of laminar and turbulent boundary layers on the outer surface of a hollow cylinder at Mach number 2.41 and a range of Reynolds numbers. Results regarding static-pressure distribution, Schileren observations, velocity profiles, boundary-layer transition, determination of effective leading edge for turbulent flow, skin friction, and probe effect are provided.

Note presenting an investigation to determine whether the use of annular ledges to promote turbulent momentum exchange will improve the performance of a short, wide-angle diffuser. Results are presented of tests of a 23 degree conical diffuser with a 2:1 ratio of exit to inlet area with both rough and smooth triangular ledges, approximately one-tenth of the inlet boundary-layer thickness in height, installed in succession from the inlet to the exit. Results regarding rough ledges, comparison between smooth and rough ledges, and effect of changing the height of the smooth ledge are provided.