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An Experimental Investigation of the Pressure Field Around a Thrust Vector Control Device.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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An experimental investigation was conducted to determine the interaction of a thrust vector control device, employing the Coanda effect, on an exhaust jet issuing from a round convergent nozzle. The thrust vector device consisted of a curved surface which the jet attached to, and sideplates on each side of this surface. Opening control ports in the surface to ambient conditions caused the jet to detach from the surface. Test positions of the thrust vector device were 6, 9, and 12 degrees surface angle, 0.00 to 0.73 inches axial distance, and 0.00 to 0.40 inches radial distance. The best operation of the device occurred with a gap present between the surface of the device and the nozzle. This allowed the exhaust jet to pump entrained secondary air over the devices surface, creating a negative pressure distribution over the surface. A position with no gap present restricted the entrainment and pumping of secondary air, causing a portion of the exhaust jet to separate from the main airstream and form a separate core of air flowing over the surface. This separation resulted in a degradation of performance lift and drag. The effects of surface angle, axial displacement, and radial displacement on the exhaust jet were found to be interrelated, and must all be considered together to find the optimum operating position of the device.
APPROVED FOR PUBLIC RELEASE