From Introduction: "The flare assumed is based primarily on reference 1, in which information permitting calculation of the flare characteristics of an airplane was obtained from flight tests. The results of calculations for airplanes having constant lift-drag ratio during the flare are plotted in chart form."

"From consideration of available information on boundary-layer behavior, a relation among profile thickness, maximum surface velocity, Reynolds number, velocity diagram, and solidity is established for a cascade of airfoils immersed in a two-dimensional incompressible fluid flow. Several cascades are computed to show the effect of various cascade design parameters on minimum required cascade solidity. Comparisons with experimentally determined blade performance show that the derived blade loadings are equal or higher for moderate flow deceleration and somewhat lower for large deceleration. Blades with completely laminar flow appear practical for impulse or reaction blading" (p. 117).

"The calculation of the phenomena within the boundary layer of bodies immersed in a flow underwent a decisive development on the basis of L. Prandtl's trains of thought, stated more than forth years ago, and by numerous later treatises again and again touching upon them. The requirements of the steadily improving aerodynamics of airplanes have greatly increased with the passing of time and recently research became particularly interested in such phenomena in the boundary layer as are caused by small external disturbances. Experimental results suggest that, for instance, slight fluctuations in the free stream velocities as they occur in wind tunnels or slight wavelike deviations of outer wing contours from the prescribed smooth course as they originate due to construction inaccuracies may exert strong effects on the extent of the laminar boundary layer on the body and thus on the drag" (p. 1).

Report presenting a study of the factors influencing the performance of aerodynamic brakes. The increases in drag coefficient that are characteristics of several types of wing and fuselage aerodynamic brakes, which have been tested in wind tunnels or in flight, are summarized in the report.

Report presenting the results of an experimental investigation of rim cracking in a welded-blade composite gas-turbine wheel, in two carbon-steel disks, and five tool-steel disks. Various characteristics were investigated, including the effectiveness of holes in preventing crack propagation and the influence of hardness and various types of notch on rim cracking.

Report presenting an experimental investigation to determine the orifice coefficient of a jet direct perpendicularly to an air stream as a function of pressure ratio and jet Reynolds number for circular, square, and elliptical orifices. The effect of air-stream velocity on the jet flow was also determined for three tunnel-air velocities.

Note presenting an experimental investigation conducted to determine the orifice coefficient of a jet directed perpendicularly to an air stream as a function of pressure ratio and jet Reynolds number for circular, square, and elliptical orifices. The effect of air-stream velocity on the jet flow was also determined for three tunnel-air velocities. Results regarding jets discharging into still air and effect of tunnel-air velocity on jet flow.

Memorandum presenting an investigation conducted to evaluate the effectiveness of a simple internal regenerative fuel preheater for a 20-inch-diameter ram jet. Data obtained at subsonic sea-level conditions indicated that fuel could be successfully preheated in this manner.

"For the design and the construction of airplanes the control is of special significance, not only with regard to the flight mechanical properties but also for the proportional arrangement of wing unit, fuselage, and tail unit. Whereas these problems may be regarded as solved for direct control of airplane motions, that is, for immediate operation of the control surfaces, they are not clarified as to oscillations, stability, and stress phenomena occurring in flight motions with Indirect control, as realized for instance in tab control" (p. 1).

The first partial report, FB 2000, contained a discussion of the derivation of the equations of motion and their solutions for a tab-controlled airplane; the results obtained there are now to be applied to the longitudinal motion of tab-controlled airplanes. In view of the abundance of structural factors and aerodynamic parameters, a general discussion of the problems is unfeasible. Thus it is demonstrated on the basis of examples what stability, oscillation, and stress conditions are to be expected for tab-controlled airplanes. (author).

Report presenting an investigation of a turbine and propeller to determine the conditions of maximum-efficiency operation when utilized as an independent turbine-propeller combination. The procedure used to determine the conditions of maximum efficiency and speed ratio between the turbine and propeller is described.

The theory of characteristics will be presented generally for quasilinear differential equations of the second order in two variables. This is necessary because of the manifold requirements to be demanded from the theory of characteristics.

Report presenting testing of low-aspect-ratio triangular-plan-form lifting surfaces located on conical and cylindrical portions of a body have been determined at Mach number 1.2 and several subsonic speeds to determine if the aerodynamic characteristics of these surfaces at supersonic speeds could be improved by locating them in the subsonic conical-flow field. Results regarding lift and drag coefficients and lift-curve slopes are provided.

"The results of analytical studies of tail-pipe-burning, water-injection, and bleedoff methods of thrust augmentation are presented that provide an insight into the operating characteristics of these augmentation methods and summarizes the performance that may be obtained when applied to a typical turbojet engine. A brief description of the principles of operation of each augmentation method is given, together with curves that illustrate the effects of the principal design and operating variables of the augmentation system on the thrust and the liquid consumption of the engine. The necessity of designing tail-pipe burners with a low burner-inlet velocity, a low burner drag, and a high diffuser efficiency in order to obtain a high thrust augmentation and to minimize the loss in engine performance during nonburning operation is illustrated" (p. 593).

From Introduction: "This paper presents the results of the investigation of the wing-alone and wing-fuelage configurations employing a wing with the quarter-chord line swept back 60^o, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section parallel to the free stream."

Report presenting a two-dimensional wind-tunnel investigation of a 6-percent-thick symmetrical circular-arc airfoil with leading-edge and trailing-edge high-lift devices. The purpose of the investigation was to determine the effects on maximum section lift coefficient of different leading-edge slats and drooped-nose flaps when used in combination with a plain trailing-edge flap. Results regarding slat configuration, drooped-nose-flap configurations, and a comparison of slat and drooped-nose-flap configurations are provided.

Memorandum presenting a method for computing the isentropic and actual enthalpy change between the inlet and outlet of a centrifugal-flow compressor when water injection is used. The method of calculation is based on fluid property values given in steam and air tables.

Report presenting an investigation of the pressure distribution over a wing with the leading-edge swept back 47.5 degrees and with symmetrical circular-arc airfoil sections in the full-scale tunnel at a designated Mach and Reynolds number. The investigation included measurements of the surface static pressures along the chord for six spanwise stations, for a large angle-of-attack range, and for several angles of yaw.

A model of the Consolidated Vultee Aircraft Corporation Skate 7 seaplane was tested in Langley tank no. 2. Presented without discussion in this paper are landing stability in smooth water, maximum normal accelerations occurring during rough-water landings, and take-off behavior in waves.

Report discussing an investigation of the aerodynamic characteristics of an airfoil-forebody swept flying boat hull with a wing and tail swept back 51.3 degrees at the leading edge. The swept hull's minimum drag coefficient was about the same as the parent model or streamline model. Various combinations of flaps were also utilized.

Report presenting a wind-tunnel investigation to determine the effect of propeller operation on the characteristics of submerged inlets. The tests were performed with a model of a hypothetical fighter airplane powered by a turbine-propeller unit. The propeller had eight blades with thin airfoil shanks and dual rotation and the submerged inlets were placed in the fuselage behind the propeller and forward of the wing.

From Summary: "A single-stage modification of the turbine from a Mark 25 torpedo power plant was investigated to determine the performance with two nozzles and three rotor-blade designs. The performance was evaluated in terms of brake, rotor, and blade efficiencies at pressure ratios of 8, 15 (design), and 20. The blade efficiencies with the two nozzles are compared with those obtained with four other nozzles previously investigated with the same three rotor-blade designs."

Memorandum describing preliminary investigations of two 3-inch-diameter slotted test sections over a range of pressure ratios from 1.3 to 10.0. The two test sections varied based on the number of slots and amount of open space, but they showed no appreciable difference in performance. Results regarding the slots with no chamber around the test section and with a closed chamber around the test section are provided.

NACA instrumentation has been installed in the Northrop X-4 airplane to obtain stability and control data during the Northrop conducted acceptance tests. The results o. the third flight of the X- ll. number 1 airplane are presented in this paper. The results of this flight showed that the directional stability as measured in steadily increasing sideslips was positive and high and that the lateral stability was positive.