Development of a Hybrid Propulsion System for VTOL drone

Abstract

This thesis is part of a project initiated by a start-up company called SEVENDOF. The thesis will address the conceptualization of various different components for a new unmanned UAV concept with VTOL capabilities called StormPetrel.

To provide the StormPetrel with a sturdy airframe that also provides lift forces in forward flight, a carbon fibre wing airframe is being developed. A carbon fibre wing construction with a foam core is chosen for a lightweight and stiff construction. In addition, a carbon fibre tube running the length of the wing will be implemented to add stiffness and function as a cable routing tube for electrical wiring. Inserts will also be added so the fuselage and internal components can be attached onto the wing. The production process is carefully planned and is presented in close detail. The design fell within acceptable margins compared to the initial weight budget that was decided upon prior to this thesis. The next step is to produce the wing for use in the prototype, as well as producing a smaller section of the wing profile for destructive testing.

The second part will address the conceptualization and design of various different components for a Hybrid Power Plant (HPP) system. A 40 CCM 4-Stroke petrol engine will be used to drive a generator in order to produce the electricity for the StormPetrels electric motors and avionics. To achieve this, a custom-made interface between the engine, generator and cooling fan was designed, as well as mounting brackets to hold the construction in place. In addition to mechanical design of the components, structural analyses has also been performed, both in SolidWorks. This design also fell within good margins relative to the initial weight budget. It is recommended to go forth with production so that the system can be further tested in a test rig.

The third and final part of the thesis will address the design of a first draft for the fuselage of the StormPetrel. The main idea is to identify a suitable method of designing the complex geometry of the fuselage by utilizing surface modelling within SolidWorks. In addition, Computational Fluid Dynamics simulations were performed to check the aerodynamic properties of the design. Both the surface modelling and the CFD simulations seem to be well suited for this purpose, and are recommended tools for further development of the StormPetrel prototype.