"Wind-tunnel tests were performed at Mach numbers of 1.5 and 2.0 to investigate the influence of tail surfaces on the base drag of a body of revolution without boattailing and having a turbulent boundary layer. The tail surfaces were of rectangular plan form of aspect ratio 2.33 and has symmetrical, circular-arc airfoil section. The results of the investigation showed that the addition of these tail surfaces with the trailing edges at or near the body base incurred a large increase in the base-drag coefficient. For a cruciform tail having a 10-percent-thick airfoil section, this increase was about 70 percent at a Mach number of 1.5 and 35 percent at a Mach number of 2.0" (p. 1).

Report presenting practical methods for making the calculations required for the analysis of an autopilot and an autopilot-aircraft combination from frequency-response data. From Summary: "Equations are derived for determining the servo-system error voltage for both displacement input signal and displacement plus rate of displacement input signals, the autopilot frequency response for addition of rate of displacement input signal, the servo-system frequency response for a change of gain, and the relation between open-loop and closed-loop frequency responses for the servo system and the autopilot-aircraft combination."

From Summary: "Values of the downwash of a horseshoe vortex in compressible flow are presented in the form of charts and tables. The use of the charts and tables in the calculations of the downwash of wings of arbitrary plan form is discussed. The results of a few calculations are compared with experimental results."

Report presenting two closely related methods which employ operations tables that have been developed and used in the calculation of buckling load of a monocoque cylinder subjected to pure bending. The buckling loads of three cylinders with very different characteristics were calculated using the methods.

Report presenting a method utilizing precalculated solutions graphically presented for calculating subsonic or supersonic ramjet performance parameters with the associated equations and graphs. By assuming constant values of specific-heat ratio and gas constant equal to those of standard air, the thrust-coefficient calculation has been reduced to a few simple operations.

Report presenting an investigation to determine the floating characteristics of full-length plain and horn-balanced rudders during rotary tests at spinning attitudes on a scale model of a typical low-wing personal-owner airplane. The investigation included the determination of the effects of the horizontal tail and the wing on the rudder floating characteristics.

Report presenting data for turbulent-velocity-fluctuation components and mean-velocity distributions measured in the subsonic jet issuing from a pipe in which a fully developed turbulent flow was established. Axial and radial components of the fluctuation velocities were examined as functions of Reynolds number and position in the jet.

"The present report covers a series of torsional tests on stiffened D-tubes of alclad 24S-T3 aluminum alloy having a cross section similar to the NACA 0012 airfoil section and a closing web at 30 percent of the chord. The stiffeners consisted of ribs and stringers. An average-strength chart has been developed for this type of structure that takes into account the skin thickness, rib spacing, and stringer spacing. This chart may also be used for unstiffened D-tubes" (p. 1).

Note presenting the particular integrals of the second-order and third-order Prandtl-Busemann iteration equations for the flow of a compressible fluid that have been obtained by means of the method in which the complex conjugate variables are utilized as the independent variables of the analysis. The forms of the particular integrals, derived for subsonic flow, are readily adapted to supersonic flows with only a change in sign of one of the parameters of the problem.

From Summary: "A literature survey was conducted to determine the relation between aircraft ignition sources and inflammables. Available literature applicable to the problem of aircraft fire hazards is analyzed and discussed herein. Data pertaining to the effect of many variables on ignition temperatures, minimum ignition pressures, and minimum spark-ignition energies of inflammables, quenching distances of electrode configurations, and size of openings incapable of flame propagation are presented and discussed."

Note presenting an account of explicit solutions in terms of Mathieu functions of the problem of two-dimensional subsonic compressible flow past oscillating airfoils. The results are applied to the calculation of three-dimensional corrections for the two-dimensional theory and the effect of the incorporation of the three-dimensional effects on the Mathieu function solution of the two-dimensional problem is shown.

Note presenting an analysis of the problem of two-dimensional flow behind a curved stationary shock wave. The method assumes a given shock-wave shape, which automatically determines certain initial conditions on flow variables, and flow-pattern, including any body shape, follows from initial conditions.

Note presenting a general integral form of the boundary-layer equation that is derived from the Prandtl partial-differential boundary-layer equation. The general integral equation, valid for either laminar or turbulent incompressible boundary-layer flow, contains the Von Karman momentum equation, the kinetic-energy equation, and the Loitsianskii equation as special cases.

From Summary: "Axial fatigue tests at zero mean stress have been made on 0.032- and 0.064-inch 24S-T and 0.032-inch 75S-T sheet-metal specimens 1/4, 1/2, 1, and 2 inches wide without a hole and with central holes giving a range of hole diameter D to specimen width W from 0.01 to 0.95. No systematic difference was noted between the results for the 0.032-inch and the 0.064-inch specimens although the latter seemed the more consistent. In general the fatigue strength based on the minimum section dropped sharply as the ration D/W was increased from zero to about 0.25. The plain specimens showed quite a pronounced decrease in fatigue strength with increasing width. The holed specimens showed only slight and rather inconclusive evidence of this size effect. The fatigue stress-concentration factor was higher for 75S-T than for 24S-T alloy. Evidence was found that a very small hole would not cause any reduction in fatigue strength."

Report presenting the use of linearized theory for compressible unsteady flow to obtain the velocity potential and lift and moment for a thin, harmonically oscillating, two-dimensional wing-aileron combination moving at sonic speed.

Report presenting an analysis of airfoil data from several NACA 16-series propeller airfoils from tests of 5-inch chord models in the 24-inch high-speed tunnel and 12-inch-chord models in the 8-foot high-speed tunnel. Results indicated that differences of less than 1 percent in propeller efficiency at or near the design condition will be involved in applying data from 5-inch-chord and 12-inch-chord airfoil tests to full-scale propeller design.

A report in two parts: one is a brief review of methods available to helicopter designers for obtaining desired stability characteristics by modifying airframe design and the other is a review of some of the methods of predicting rotor stability derivatives.

"Three-dimensional interaction surfaces are presented for the computation of elastic buckling stresses for an infinitely long flat plate subjected to combinations of bending, shear, and transverse compression in its plane - a loading approximating that occurring in a shear web. Surfaces are presented for two sets of edge conditions: both edges simply supported and lower edge simply supported, upper edge clamped. Present results are in good agreement with data for one-load and two-load limiting cases previously published" (p. 1).

Report presenting turbulent-heat-transfer measurements obtained through the use of an axially symmetric annual nozzle consisting of an inner shaped center body and an outer cylindrical sleeve at Mach number 2.06. Results regarding the variation of wall temperature with longitudinal distance, variation of local Nusselt number with local Reynolds number, and variation of local temperature-recovery factor with local Reynolds number are provided.

Note presenting the results of an investigation consisting of a series of one-engine climb tests with a twin-engine transport airplane, which indicate that light turbulence of the type generally present in clear air over flat terrain has no significant effect on the average rate of climb for a series of runs. Turbulence does, however, increase the variation in the rate of climb from run to run. Results regarding mean rate of climb, standard deviation of the rate of climb, effects of climb duration, and implications of these results are provided.

Report presenting experimental data obtained in the 4- by 4-foot supersonic tunnel for a parabolic body of revolution of large fineness ratio at mach number 1.59, which are analyzed in order to locate positions at which static-pressure orifices will indicate a constant static pressure independent of the pitch-yaw attitude of the body.

Note presenting a review of the literature on the sonic studies of the problem of the excitation of molecular vibrations by collision. The theory on which the interpretation of almost all the sonic work has been based is discussed rather qualitatively in some detail. Results concerning techniques, principal experimental programs, and an interpretation of the results are provided.

Note presenting an investigation to determine the effects of wing position on the low-speed static longitudinal and static lateral stability of airplane models with fuselages of square and rectangular cross sections and unswept and 45 degree sweptback surfaces. The results of the investigation indicated that at low angles of attack, the complete unswept models with the wing in the high position were more stable or least longitudinally unstable. The results also showed that wing-fuselage interference causes an increase in effective dihedral angle when the wing is moved to the high position.

Report presenting three modifications to the leading-edge region of the NACA 64A010 airfoil section, which were designed and tested two-dimensionally at both low and high subsonic speeds. The modifications increased the low-speed maximum lift coefficient of the symmetrical reference section, largely by increasing the angle of attack at which stall occurred.