From Introduction: "The purpose of the present paper is to show in more detail the possibilities end the limitations of the use of regeneration as a means of effecting greater fuel economy and of reducing the net weight of the power plant and fuel of compressor-turbine-propeller aircraft engines."

An investigation was conducted to determine the effects of three design modifications of the original NACA injection impeller on the performance of an R-3350 engine. Different methods of injecting the fuel into the impeller air stream were studied and evaluated from the individual cylinder fuel-air ratios and the resulting cylinder temperatures. Each impeller was tested for a range of engine powers normally used in flight operation. The relatively simple design of the original injection impeller produced approximately the same mixture- and temperature-distribution characteristics as the modified impellers of more complex design. None of the modifications appreciably affected the manifold pressure, the combustion-air flow, nor the throttle angle required to maintain a given engine power,.

From Summary: "The results of numerous unrelated tests of dive-recovery flaps are collected in this report and presented in a form suitable for use in the preliminary design of dive-recovery flap installations. Since the data were obtained for airplane models of quite widely varying configurations, and are limited largely to a Mach number of 0.80, it is recommended that each new installation be carefully flight-tested before final approval. A flight-test procedure is outlined which will insure a maximum degree of safety."

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.

Report presenting wind-tunnel tests that have been conducted to evaluate the independent effects of Reynolds and Mach numbers on the aerodynamic characteristics of a horizontal tail of aspect ratio 4.5 with a plain sealed elevator with a tab. Lift, drag, pitching moment, elevator hinge moment, tab hinge moment, streamwise distribution of static pressure at the midsemispan, and pressure difference across the elevator-nose seal were measured.

Report presenting an investigation in the high-speed tunnel to determine the effect of sweep on the static lateral stability characteristics of wing-fuselage combinations with wings of aspect ratio 4 and taper ratio 0.6 at high subsonic speeds. Results regarding rolling-moment characteristics and lateral-force and yawing-moment characteristics are also provided.

Report presenting an investigation to determine the effect of circumstantial inlet location on the performance of twin half-conical scoop-type inlets with and without boundary-layer removal at several Mach numbers and angles of attack. For positive angles of attack, higher pressure recovery performance was obtained with the inlets mounted on lower fuselage quadrants than on upper quadrants.

Memorandum presenting measurements of the oscillatory lift force acting on an airfoil vibrated in bending. Results were obtained for an isolated airfoil and for the same airfoil oscillated in a cascade, at low and high angles of attack.

"An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph" (p. 1).

Report discussing an investigation of the dynamic stability and control characteristics of a model of the Ryan X-13 jet VTOL airplane in hovering and transition flight. Flight control was smooth and easy without the gyroscopic effects of the engine represented, but adding a simulation of the gyroscopic effects caused the plane to become uncontrollable in hovering flight without artificial stabilization. The transition was found to be easy to perform with and without gyroscopic effects, but the model had a tendency to fly in roll and slideslipped attitudes.