Experimental Evaluation of an Electric Powertrain Designed for a 180-kw Turboelectric Aircraft Ground Test Rig

This paper presents the experimental results of a representative aircraft turboelectric powertrain. The 180-kW hybrid gas-electric ground test rig was designed, fabricated, and experimentally evaluated for safe integration. Hybrid turboelectric power systems enable future medium- to long-range electrified aircraft, offering higher energy density over current battery technologies. Previous studies have focused on analytical models of turboelectric systems. However, as industry stakeholders continue to advance toward hybrid turboelectric aircraft, there is a need for practical knowledge regarding their implementation. The objectives of this study are two-fold. First, the study aims to evaluate the real-time transient performance of turboelectric aircraft. The second objective aims to characterize the real-world challenges of safely constructing and operating a hybrid turboelectric aircraft. To satisfy these objectives, a ground test vehicle was constructed from a modified Cessna-172 aircraft, a modified 180-kW PBS-TP100 turboprop, two wing-mounted electric motors, and a purpose-built turboelectric powertrain. The engine was brought to full power and the electric motor power was varied. Experimental observations are made regarding interdependent time responses of the electro-mechanical systems. Test run results include engine performance metrics, current, voltage, and acoustic data. The generator peaked at 4-kW and was augmented by 13-kW battery power to drive distributed propulsors. Practical recommendations for safe integration are identified, such as a pre-charge circuit, crowbar circuit, and short protection circuits. This study provides insight into the design and practical implementation of turboelectric power systems for future electrified aircraft.