Development of a Design Process for Solar-Powered HALE Aircraft Configurations

High-flying autonomous aircraft are meant to be deployed in the stratosphere for days or even months. These aircraft share different applications from and several advantages over satellites. Therefore, such aircraft are an interesting subject for research and commercial applications. They are expected to be powered by solar energy and thus heavily depend on their mission profile. An integrated, multidisciplinary design process is proposed to provide a fast way to evaluate an extensive parameter space while requiring minimum input parameters. This process is realised by developing a process which incorporates several critical disciplines required for a high-flying autonomous aircraft, implemented into a software-tool. The underlying disciplines include the basic aerodynamics and structural analysis of an aircraft, which must be connected with a mission analysis approach, considering the constantly changing irradiation conditions and the resulting aircraft power management and constant re-evaluation of aircraft parameters. The aircraft’s dependence on solar energy led to the implementation of a time-based, iterative sizing approach which relied on handbook formulas and empirical estimation methods. The tool ultimately consists of different levels, permitting the use of a core process to evaluate aircraft configurations and missions and provide aircraft performance estimates for researchers and designers. This core process can further be used by outer levels for parametric studies, enabling users to change the basic parameters of the aircraft or the mission definition. These studies can be used to compare aircraft parameter configurations or to conduct use case analysis of a given aircraft. The tool is shown to be capable of evaluating the parameter space for the intended aircraft and mission configurations. Exemplary studies using the mission analysis algorithm revealed that the results where highly sensitive to irradiation compared to what was expected from earlier studies from the literature, ultimately influencing all aircraft parameters due to highly dynamic parameter relations. For example, the effect of adjustable solar panels can be rated using simple comparison experiments, which attest an efficiency increase for low irradiation angles with adjustable panels despite an included drag and weight penalty. This thesis and the included methods helps to close a gap between analytic aircraft analysis approaches and CPU-intensive 3D-simulations for high-flying autonomous aircraft. Future projects will have a detailed overview of battery management required for high-flying autonomous aircraft, and a process supporting aircraft assessment and design for faster research and development.Aerospace Engineerin