System-level modelling and optimisation of a recuperated micro gas turbine hybrid power system for eVTOL endurance enhancement

A micro gas turbine (MGT) based hybrid power system is a promising solution for extending the endurance of mid to large electric vertical take-off and landing (eVTOL) aircraft. Integrating a recuperator can improve thermal efficiency, but the added mass must be carefully balanced against the resulting performance gains. This study develops a system-level computational framework for an eVTOL equipped with a recuperated MGT, integrating recuperator characteristics, MGT operating behaviour, and aircraft-level performance to quantify the influence of recuperator structural parameters on flight endurance. A genetic algorithm is employed to optimise the structural parameters of the recuperator, with the aim of maximising the continuous flight duration under various operating conditions. The results reveal that, for the studied 30 kW-class MGT system, incorporating a recuperator of 5.8 kg and a heat transfer effectiveness of 58.84% can extend flight time by approximately 30% and achieve a tenfold increase over battery-powered systems. These findings indicate that optimised recuperated MGTs can offset mass penalties through efficiency gains, significantly improving eVTOL flight endurance and demonstrating a viable alternative to battery-powered configurations.