Fluidic thrust vectoring for low observable air vehicles

An experimental investigation into fluidic thrust vectoring technology has been conducted at the Goldstein Research Laboratory, University of Manchester, UK. Pitch only thrust vectoring of the primary exhaust jet was achieved by using tangential injection of a secondary control jet - the coflow technique. The work aims to highlight practical engineering issues surrounding the implementation of a fluidic thrust vectoring propulsion system into a low observable unmanned air vehicle. A non-swept and a swept exhaust nozzle were designed and a small-scale turbojet engine was used to provide the primary exhaust jet and axial forces. Both nozzles investigated exhibit almost entirely linear control response characteristics. However, swept nozzle performance is greater than non-swept nozzle performance over the blowing coefficient range investigated. At a primary jet Mach number of 0.33, the non-swept nozzle generates a thrust vector force equal to 6% of the non-vectored axial force. This is achievable at a secondary jet momentum flow rate equal to 10% of the primary jet flow. Under these conditions, non-swept nozzle thrust vectoring efficiency is 0.6. In contrast, the swept nozzle generates a thrust vector force equal to 17% of the non-vectored axial force under the same conditions, resulting in a swept nozzle efficiency of 1.7. © 2004 by the American Institute of Aeronautics and Astronautics, Inc.