Volume 1 - Issue 4, November - December 2025

This study examines the effect of engine injection airflow on the aerodynamic performance of an aircraft equipped with a multidirectional thrust-vectoring turbofan engine. Using the MiG-21 as a baseline platform, the original R11F-300 turbojet was replaced with a next-generation dual-stream engine to assess changes in aerodynamic behavior across various nozzle and horizontal-tail deflection angles. Three-dimensional thermo-aerodynamic simulations were performed in ANSYS CFX for multiple flight regimes at altitudes of 1 km and 10 km and a cruising Mach number of 0.45. The results indicate that deflected jet flow significantly modifies the surrounding pressure field, enhances or reduces effective thrust depending on the control-surface configuration, and strongly influences lift and lateral forces. Flow asymmetry, vortex formation behind deflected surfaces, and interactions between the jet plume and wake structures were clearly observed. These findings confirm that injection airflow and thrust-vectoring contribute substantially to maneuverability, especially during high-angle-of-attack or asymmetric control conditions. The study provides a basis for optimizing jet-flow control strategies for advanced high-agility aircraft.