Report presenting an investigation to determine the effect of blade-section camber on the stall-flutter characteristics of three propellers using a 6000-horsepower propeller dynamometer. Up to a certain blade angle, there was an increase in flutter-speed coefficient with an increase in blade-section design lift coefficient. An increase in thrust was found to lead to an increase in tip Mach number in the flutter region of the propeller blades.

Memorandum presenting a direct-connect duct investigation conducted with a one-quarter segment of a 25.5 inch diameter annular combustor which had been previously developed for liquid fuel injection. The combustor was modified by changing the fuel injectors and the liner design for vapor fuel injection. Results regarding accuracy and reproducibility, combustion efficiency, combustor-outlet temperature profiles, and pressure losses are provided.

Report presenting a direct-connect duct investigation conducted with a one-quarter segment of a 25.5-inch-diameter annular combustor that had been developed for liquid fuel injection. The combustor was modified by changing the fuel injectors and liner design for vapor fuel injection. Results regarding accuracy and reproducibility, combustion efficiency, combustor-outlet temperature profiles, and pressure losses are provided.

An experimental investigation of the performance of a single-conical-shock diffuser was conducted at a Mach number of 5.4 and a Reynolds number based on model diameter of 375,000. Total-pressure recoveries of 13.7 and 13.1 percent were obtained at angles of attack of 0 degrees and 3 degrees, respectively. The corresponding kinetic energy efficiencies were 86.4 percent at an angle of attack of 0 degrees and 86.0 percent at an angle of attack of 3 degrees.

"Theoretical design charts based on Neuber's equations for symmetrically located notches are presented for estimating the approximate rupture strengths of blade roots made from brittle materials. The limit of applicability of the theoretical charts is shown as determined by rupture tests of plastic models. The optimum proportions among over-all root width, neck width, notch radius, and notch depth are determined from the design charts" (p. 1).

"Ignition of the fuel-air mixture in an afterburner of turbojet engine at altitude has often proved to be a different problem to solve. Electrical ignition has not proven satisfactory because of the unreliability of such systems (ref. 1). The ignition data reported herein were obtained for two after-burner configurations. Autoignition data are included for both configurations and hot-streak-ignition data, for only one. "

Report presenting an experimental investigation to determine the aerodynamic characteristics of a slender cone-cylinder body of revolution in the 1- by 1-foot supersonic wind tunnel. Viscous drag and three component forces were measured at Mach number 3.12 and a range of Reynolds numbers and angles of attack. Results regarding pressure distributions, boundary layer, and forces are provided.