US Patent 7806365 Long endurance hydrogen powered vehicle

Hydrogen powered air vehicles that in some embodiments can fly with very long endurance (10 or more days) at altitudes over 60,000 ft carrying payloads of up to 2,000 pounds. Embodiments may include features such as large wingspan relative to fuselage and an all composite or partial composite structure for light weight and strength. The aircraft of the invention use one or more internal combustion engines adapted for hydrogen combustion, each engine driving propellers. The hydrogen fuel is stored on board in containers, located within the fuselage, as a cryogenic liquid, and is vaporized in a heat exchanger before delivery to the internal combustion engine.