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The novelty here seems to be that they used liquid hydrogen instead of gaseous hydrogen on a fuel-cell powered, piloted, electric aircraft. This doubled the ran

• adrian_b 3y ago
  Yes, but they only use vague words without any numbers that could support their claims that hydrogen is viable as an aircraft fuel. They should show the weights, volumes and costs for standard kerosen tanks and their liquid hydrogen tanks with the associated equipment, e.g. pumps, at the same stored energy. At equal stored energy, the liquid hydrogen tanks must be much bigger and much more expensive, and as soon as they are partially empty they will also be heavier than the partially empty kerosen tanks. The maintenance costs and the risks of failure for the cryogenic equipment will also be much greater. They do not say any word about any new technique used in their hydrogen fuel cells. All the kinds of hydrogen fuel cells remain too expensive, either due to using too expensive catalysts or because they have parts with a short lifetime, which must be replaced periodically, e.g. fluoropolymer membranes for low-temperature fuel cells or ceramic electrolytes (e.g. of ceria or zirconia) for high-temperature fuel cells.
• p_l 3y ago
  cryogenic hydrogen was always the centerpiece of hydrogen powered flight. IIRC gaseous simply didn't have the right energy density to be viable. cryogenic also increased efficiency of jet engines and opened avenues for higher speeds (Tu-244 design, for example, for ~ Ma 3 supersonic transport plane)