AN EXPERIMENTAL INVESTIGATION OF NEW CONCEPTS IN EJECTOR THRUST AUGMENTATION FOR V/STOL.
Final technical rept. Jun 68-Jun 69,
FLIGHT DYNAMICS RESEARCH CORP BURBANK CALIF
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The basic concept involved in the investigation is the utilization of the Coanda effect in combination with an external cascade of airfoils. That combination served to achieve a more efficient rotation and amplification of the jet thrust vector as a result of both the large induced mass flow from the environment and the simultaneous high lift of the cascaded airfoils. The program objective was to establish optimal performance by systematic variation of the pertinent parameters. Experimental results showed a gain of 20 in augmented thrust compared to that of a simple Coanda cylinder. Since the observed mass flow through the airfoil cascade was small, in-house tests were performed with diffusion. The resultant increase in secondary mass flow produced a gain of 65 in thrust augmentation over the tests without diffusion despite large regions of flow separation in the diffuser. It appears highly probable that further large gains can result from precise diffuser design and boundary layer control in the diffuser. Author