Kinematic Design and Control Analysis of A Subsonic Ejector Nozzle with Omni-Directional Thrust Vectoring for Afterburning Turbofan Engines

ABSTRACT This paper presents the development and analysis of a kinematic scheme for a subsonic ejector nozzle equipped with omni-directional thrust vector control (TVC) for an afterburning turbofan engine intended for advanced maneuverable aircraft. The study examines existing thrust-vectoring nozzle concepts, identifies their limitations, and evaluates the applicability of known design solutions to next-generation turbofan configurations. A new kinematic scheme is proposed that builds on the variable-geometry subsonic nozzle of the AI-222-25F engine and integrates an ejector section and multiaxis flap actuation system. Detailed geometric modeling and kinematic analysis are performed for two perpendicular rotation planes, allowing the derivation of analytical relationships between control-ring orientation and flap deflection. An analytical method is introduced for computing hydraulic-cylinder strokes based on the normal-vector angle of the control ring, ensuring precise mapping between commanded thrust-vector angles and actuator motion. The resulting nozzle configuration achieves omnidirectional thrust-vector deflection of 15° and a 1.33× throat-diameter variation. The study provides a foundation for integrating the proposed nozzle into an aircraft layout and for future refinement considering structural constraints, thermal loads, and material selection.