A New Modelling Method for a Turbojet Engine Based Vector Control Through a 1-Axis Force Measurement

The application of vector thrust technology promotes the manoeuvrability of aircraft, which fulfils the requirements of the modern aviation industry for multiple characteristics of the aircraft. Meanwhile, it also brings the development of vectorial thrust testing technology. Compared with traditional jet engines, modelling a vectorial thrust is more complicated and requires a more accurate measurement of the value and direction of the thrust. In this paper, we have used a 1-axis force transducer as the core to implement a thrust test bench and conduct thrust and jet deflection tests on a small turbojet engine assembled with a shaped nozzle and jet control surface. The obtained engine thrust and jet control data shows that: 1) replacing the six-dimensional force/moment sensor with a single-degree-of-freedom force transducer is feasible for the modelling of the vector thrust system, which reduces the cost of calibration of the jet control system greatly; 2) The engine thrust and the deflection control force of the jet rudder maintain a good linear relationship with the dynamic pressure of the nozzle; 3) The maximum thrust loss of the engine equipped with the shaped nozzle is about 10%, and there will be an additional 3.75% thrust loss when the jet rudder deflection angle is at the maximum.