Analysis of a Hybrid Partial Turboelectric Distributed Propulsion System for a Medium Altitude Long Endurance UAV

Electrified propulsion offers high efficiency, scalability, and high power discharge capability which can be utilized for increased agility and directed energy applications in unmanned aerial vehicles (UAV). However, the limited energy density of state-of-the-art batteries creates a technological bottle-neck, penalizing the payload and range capabilities compared to conventional propulsion aircraft. This paper is a part of a series of publications that aim to design, assess, and compare various electrified propulsion system architectures on a common UAV testbed. In this paper, a hybrid partial turboelectric distributed propulsion (HPTeDP) system and its thermal management system were designed and analyzed. The battery was managed as a supplementary energy source used only during certain mission segments that require high power. A thermal management system was designed to manage the excess heat generation from the onboard battery, generator, and electric motors. The HPTeDP and thermal management systems were sized under the fixed geometry, maximum takeoff weight and point performance requirements of the conventional testbed. The payload-range capability of the HPTeDP UAV was compared to the conventional, series distributed and turboelectric distributed UAVs designed under the same requirements used in previous studies.