The diesel engine is the most appropriate power plant for near-term long duration air ships. Brayton has designed the complete propulsion system for the Cyber Defense Systems MAA-90 airship (90 feet diameter), including structures and mounting systems, drive-train with right-angle articulating gear box for vector control, optimized propeller (5.5 meter diameter), heat exchanger upgrades, fuel system, and fuel-derived water condensate recovery system. Additionally we have analyzed the stock turbocharger and proposed simple upgrades to improve SFC and power. This diesel-powered system is an interim step in the development of a long-duration solar-powered UAV, for which Brayton has conducted conceptual design studies. This work is supported by Cyber Defense Systems and Sierra Nevada Corporation.