Comparison of Design Methods for Fuel-Cell-PoweredUnmanned Aerial Vehicles

Abstract

This paper presents two comparisons of design methods for fuel-cell-powered unmanned aerial vehicles. Previous design studies of fuel-cell-powered aircraft have used design methods that contain intrinsic assumptions regarding the design of a fuel cell powerplant and regarding the interactions between the powerplant and aircraft application. This study seeks to understand the effects of these design assumptions on the fuel cell powerplant structure and the aircraft performance. A design methods comparison is constructed by first developing a multidisciplinary modeling and design environment that is more general than the design processes proposed in literature. The design processes from previous studies can then be imposed on the more complete design environment to determine the performance costs and morphological changes caused by the design assumptions. In the first design study, results show that designing fuel-cell-powered aircraft using automotive-type fuel cell design rules leads to a low-efficiency powerplant and a low-performance aircraft in long-endurance and long-range unmanned aerial vehicle applications. The second design study shows that designing the aircraft powerplant using powerplant design criteria (such as specific energy) rather than aircraft design criteria (such as range) leads to suboptimal aircraft performance, especially for long-endurance unmanned aerial vehicle applications. The results of these studies show that the application-integrated design of aviation-specific fuel cell powerplants can significantly improve the performance of fuel-cell-powered aircraft for a variety of scales and missions.