Effects of Transient Power Extraction on an Integrated Hardware-in-the-Loop Aircraft/Propulsion/Power System

As aircraft continue to increase their power and thermal demands, transient operation of the power and propulsion subsystems can no longer be neglected at the aircraft system level. The performance of the whole aircraft must be considered by examining the dynamic interactions between the power, propulsion, and airframe subsystems. Larger loading demands placed on the power and propulsion subsystems result in thrust, speed, and altitude transients that affect the aircraft performance and capability. This results in different operating and control parameters for the engine that can be properly captured only in an integrated system-level test.

While it is possible to capture the dynamic interactions between these aircraft subsystems by using simulations alone, the complexity of the resulting system model has a high computational cost. This paper investigates the possibility of using hardware-in-the-loop (HIL) power extraction with real time simulation of the airframe and propulsion subsystems. This method captures the interdependency of engine performance during transient shaft loading (to produce electrical power) and aircraft system-level changes that result from the same power extraction. The dynamic interactions between aircraft subsystems highlight the need for system-level analysis using a combination of high-fidelity computer models and hardware in a real-time environment to fully and accurately understand system-level capabilities and stability.