The nonwhirling propulsive characteristics of a helicopter-type pulse-jet engine mounted on a simulated helicopter rotor blade have been determined in the Langley 16-foot transonic tunnel. Propulsive characteristics as a function of fuel-flow rate were determined at Mach numbers of 0.25, 0.3, 0. 4, 0.5, and 0.6 at yaw angles of 0 deg, 10 deg, and 20 deg. The results indicate that the maximum engine propulsive thrust was about 1 pound per square inch of frontal area up to a Mach number of 0.45. At Mach numbers of 0.5 and 0.6 the maximum propulsive thrust decreased to 0.94 and 0.73 pound per square inch, respectively. A minimum specific fuel consumption of 5.3 pounds of fuel per hour per horsepower occurred between Mach numbers of 0.4 and 0.5. The data indicate that the yaw angles investigated have little effect on the engine propulsive characteristics. A comparison of the nonwhirling and whirling data obtained from NACA RM L53L15 on engines of the same design indicates that the pulse-jet engine thrust may be severely penalized as a result of centrifugal distortion of the fuel spray pattern. This effect appears at a centrifugal acceleration of about 200 g.
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