Note presenting a method of visualizing air-flow patterns by observing the motion of finely divided particles of balsa wood introduced into the air. Photographic results obtained by this method for small-scale models of several helicopter rotor configurations in the static-thrust condition are presented. The results indicate the feasibility of using the balsa-dust technique for obtaining useful qualitative information on the air-flow patterns for transient conditions as well as for steady-state conditions.

"Differential equations and boundary conditions are derived for the bending and buckling of sandwich plates. The buckling load is calculated for a simply supported plate subjected to edgewise compression. The formulas are evaluated numerically and the results are plotted in a diagram" (p. 1).

Note presenting a wind-tunnel investigation of the NACA 64A010 airfoil section to determine the boundary-layer and stalling characteristics at low speed. The tests were made at a Reynolds number of 4.1 million and included force measurements, pressure-distribution measurements, flow studies by the liquid-film technique, and boundary-layer measurements.

Report presenting an investigation in the free-flight tunnel for the purpose of comparing the dynamic lateral control characteristics of airplane models with round- and sharp-leading-edge wing sections. The two dynamic models used in the investigation had different mass characteristics and had different types of inertia. Results regarding the interpretation of flight-test results, high-inertia model, and normal-inertia model are provided.

Note presenting an investigation made in the 300 mph 7 - by 10-foot tunnel to determine the effects of various sizes and shapes of end plates on the aileron characteristics and on the aerodynamic characteristics in pitch and yaw of a wing of aspect ratio 2 with no taper and a sweepback of 45 degrees and of a wing of aspect ratio 4, taper ratio 0.6, and sweepback of 46.7 degrees. The addition of end plates to the swept wings increased the lift-curve slope, reduced the maximum lift-drag ratio, generally decreased the maximum lift coefficient, and increased the longitudinal stability slightly in the low lift coefficient range.

Report presenting a wind-tunnel investigation of a series of modifications to the leading-edge region of the NACA 63(sub 1)-012 airfoil section to determine the possibilities of delaying the flow separation that occurs near the leading edge of the basic section and improving the stalling characteristics. Results regarding the effect of the leading-edge modifications and effect of leading-edge flap are provided.

Report presenting measurements of elevator-stabilizer effectiveness and trim of the X-1 airplane at 40,000 feet altitude at a range of Mach numbers and normal-force coefficients.

Note presenting general differentiation formulas for successive derivative of a function, which are obtained in terms of the values of the function at unequally spaced arguments and the corresponding distances between the successive arguments using Lagrangian polynominals of various degrees. A general discussion of applying the formulas to the numerical solution of partial differential equations is made.

"The Navier-Stokes equations of motion and the equation of continuity are transformed so as to apply to an orthogonal curvilinear coordinate system rotating with a uniform angular velocity about an arbitrary axis in space. A usual simplification of these equations as consistent with the accepted boundary-layer theory and an integration of these equations through the boundary layer result in boundary-layer momentum-integral equations for three-dimensional flows that are applicable to either rotating or nonrotating fluid boundaries. These equations are simplified and an approximate solution in closed integral form is obtained for a generalized boundary-layer momentum-loss thickness and flow deflection at the wall in the turbulent case" (p. 1).

Report presenting a graphical method for obtaining the two-dimensional supersonic flow with moderate heat addition. The basic equations were derived for flows in which the total temperature has a continuous variation with displacement in the direction of the flow.

Report presenting an experimental investigation of the effect of several oil introduction parameters on the temperature of 75-millimeter-bore cylindrical-roller, inner-race-riding cage-type bearings over a range of DN values and static radial loads with single-jet circulating oil feed. Results regarding effect of radial location of oil jet, angle of impingement, effect of jet diameter, power required for oil delivery, and velocity effect are provided.

Effect of distributed boundary-layer suction on operating pressure ratio of a supersonic wind tunnel was investigated. Investigation was made in 3.84- by 10-inch supersonic tunnel operating at Mach number 2.0 and suction was applied in neighborhood of the normal shock to two walls of a constant-area extension of test section. A reduction of 4 percent of operating pressure ratio was attributed to improved flow conditions at subsonic-diffuser inlet. The theoretical normal shock was, in practice, replaced by a multiple-branch shock configuration across which the flow parameters changed in approximate accordance with the Rankine-Hugoniot values.

An experimental investigation is made of the turbulent flow of water in pipes with various degrees of relative roughness. The pipes range in size from 25 to 100 millimeters in diameter and from 1800 to 7050 millimeters in length. Flow velocities permitted Reynolds numbers from about 10 (sup. 4) to 10 (sup. 6). The laws of resistance and velocity distributions were obtained as a function of relative roughness and Reynolds number. Mixing length, as described by Prandtl's mixing-length formula, is discussed in relation to the experimental results.

Note presenting the application of a new back-reflection X-ray diffraction technique, which was developed through use of a multiple-film camera containing four parallel films separated by known distances. Diffraction angles were calculated by determining the change in radius of the diffraction ring from film to film. A multiple-film-technique analysis and a conventional-method analysis of the same X-ray strain data indicated that a more detailed analysis of atomic strain could be obtained from the multiple-film technique.

"The existing theory of detonation is critically examined. It is shown that the considerations with which the steady value of the velocity of detonation is chosen are not convincing. In connection with the problem of the process of the chemical reaction in a detonation wave, the objections raised against the conceptions of Le Chatelier and Vieille of the 19th century with regard to the ignition of the gas by the shock wave are refuted" (p. 1).

Note presenting a theoretical investigation made to determine the effect of nonlinear stability derivatives on the lateral stability of the airplane. The results indicated that under certain conditions, a motion is obtained which has different rates of damping for the large and small amplitudes of motion, with very little damping at the small amplitudes.

Report presenting a method for the approximate calculation of the stresses and distortions in a box beam representing the main structural component of a swept wing with a carry-through section and with bulkheads perpendicular to the spars. Results regarding determination of shear-leg effects, effect of bulkhead flexibility, and extension of the method are provided.

Note presenting an analysis of the flow around cones without axial symmetry and moving at supersonic velocity. The results of the analysis are applied to the determination of flow around circular cones at small angles of attack. It is shown that good agreement with experimental results can be obtained from the first-order theory if the complete equation for the pressure distribution is used.

"Tabulated pressure coefficients and aerodynamic characteristics are presented for six spanwise stations on the left wing of the Bell X-1 research airplane. The data were obtained in 10 pull-ups at Mach numbers from 0.53 to 0.99" (p. 1).

A heat-transfer investigation was conducted with air in an electrically heated platinum tube with long-approach entrance, inside diameter of 0.525 inch, and effective heat-transfer length of 24 inches over ranges of Reynolds number up to 320,000, average inside-tube-wall temperature up to 3053 degrees R, and inlet-air temperature up to 1165 degrees R. Correlation of data by the conventional Nusselt relation resulted in separation of data with tube-wall temperature. Good correlation was obtained, however, by use of a modified Reynolds number.

Data are presented for the fundamental flame velocities of 10 pure alkadienes that have isolated, conjugated, or cumulative double-bond systems. On the basis of this limited amount of data and the flame velocities previously reported, it is concluded that unsaturation changes the flame velocity in the order alkanes ? alkenes ? alkadienes with isolated double bonds ?= alkadienes with conjugated double bonds ? alkadienes with cumulative double bonds ?= alkynes. There were no significant differences in the flame velocities of cis and trans 1,3-pentadiene. The alkadienes 1,2-pentadiene and 2,3-pentadiene, with different positions of the cumulative double bond in the straight chain, have similar flame velocities. Methyl substitution in a hydrocarbon reduces the flame velocity; the extent of the reduction increases with the degree of unsaturation of the hydrocarbon.

Altitude-test-chamber investigation of effects of flame-holder blocked area and gutter width on performance of 28-inch diameter ram jet at simulated flight Mach number of 2.0 for altitudes from 40,000 to 55,000 feet was conducted at NACA Lewis laboratory. Ten flame holders investigated covered gutter widths from 1.00 to 2.50 inches and blocked areas from 40.5 to 62.0 percent of combustion-chamber area. Gutter width did not appreciably affect combustion efficiency.

Report presenting an analysis of a number of free-flight transient responses resulting from small stabilizer movements obtained during testing of the Bell X-1 airplane to obtain its longitudinal stability characteristics. A comparison of flight data and model test data is also provided.

Report presenting an investigation of three air inlets designed for use at transonic speeds conducted in the 8-foot high-speed tunnel. The basis of the design of the inlets was the use of a nose which was shaped so that substream velocities are maintained on its surface for high-speed operating conditions. Results regarding impact pressure recovery, external pressure distributions, wake-survey drag, supersonic external pressure drag, and design considerations are provided.