Sizing and Simulation of a Piston-prop UAV

A sizing and simulation platform has been developed for the optimization of advanced configurations for aircrafts including, but not limited to, more electric, hybrid-electric, turbo-compound piston engines and fuel cell systems. In the present investigation the software has been applied to the simulation of a medium-altitude, medium-endurance unmanned aerial vehicle (UAV) equipped with a two-stroke diesel engine with a single stage turbo-compressor. The engine was simulated with a 1D code (AVL-Boost) taking into account several values of speed, air-fuel ratio and flight altitude. The behavior of the waste-gate valve at the different flight levels was also accounted for. The Willans line method is used to obtain the seal level and in flight performance map of scaled engines with the same configuration. The power requests of a reference 128 kW engine and two scaled engines along the mission have been compared with the available power to discuss the potentiality of hybrid electric and turbo-compound configurations.