Hydrogen Powered Plane

Density of jet fuel is 840 g/L, approximate energy density per weight is 43 MJ/kg and per volume is 36 MJ/L. Density of hydrogen is 70.85 g/L, approximate energy density per weight is 142 MJ/kg and per volume is 10 MJ/L. In addition to these values, the cryogenic tank of hydrogen weights several orders more than a typical jet fuel tank. The result, much higher volume of hydrogen is required compared to jet fuel to establish the same task.

A successful hydrogen powered plane requires completely new approach in the plane design philosophy. On a hydrogen plane, the fuel tank would be at the center of the design. Whereas with traditional planes, the airframe is in the center of the design. You may see the cryogenic tank like the chassis of a truck. On a truck, everything is mounted on and around the chassis which structurally supports the object in its construction and function. The cryogenic tank is way stronger than an airframe. Therefore, the remaining airframe housing the passenger cabin can be built with less structural strength. The wings would also be attached to the hydrogen tank so as the landing gears. However, I have a VTOL proposition for the hydrogen plane using the VTOL assistor. Ariane 6 rocket which also uses liquified hydrogen as propellant has solid booster for takeoff. Like the Ariane rocket the hydrogen powered plane can also use assistance during takeoff and landing via the VTOL assistor. This negates the need for landing gears, but requires safety parachutes for the emergencies. Placing the very strong hydrogen tank on the bottom of the plane protects the airframe above during emergency landing using parachutes. Like the LNG plane I proposed earlier, the liquid hydrogen can be released before emergency landing which would also generate passive thrust.

The hydrogen tank would take up the space of baggage compartments. Therefore, the baggage would be stored at the back of the cabin like in passenger railroad cars. This would make the plane longer compared to its similar capacity counterparts.

Due to so many technical challenges and higher cost of manufacturing, the hydrogen planes can never be a mainstream choice. However, LNG powered planes may find some potential among the aviation industry.