Preliminary Design of a Solar-Powered Hybrid Airship

Abstract

The feasibility of a solar-powered hybrid airship where lift is generated by both buoyancy and aerodynamics is investigated using aerodynamic shape optimization. The design objective is to minimize the product of envelope root chord and span (which corresponds to the size of the hangar required to house the airship), subject to constraints on the lift, the ratio of solar power produced to power consumed, the airship operational empty weight, the trim, and the static margin. Simple mass models are used to estimate the mass of airship components, including the solar array, drive train components, and envelope fabric. The optimizer has the freedom to vary the envelope section shapes, span, twist, angle of attack, and flap angle. A three-point optimization has produced a feasible envelope geometry that satisfies the design requirements at two cruise-speed operating conditions (each with a center-of-gravity location at either extreme of the design range) and one low-speed operating condition. The results indicate that such an aircraft, which could be well suited to operations in remote areas, is feasible with respect to aerodynamic efficiency. Sensitivity studies indicate that faster hybrid airships will become feasible with future improvements in solar panel irradiance.