Dec 192014
In the early/mid 1970s the US aerospace industry studied alternate fuels for aircraft. This included liquid hydrogen… a pain to work with, but it makes a great fuel and can be processed easily out of natural gas, less easily out of coal, and with a whole lot of electricity out of water. But it is extremely cold and extremely low density. Thus when Lockheed (apparently half-heartedly) looked at an LH2 version of the C-141, it looked like this:
Under normal conditions, wingtip fuel tanks that vast would snap the wings right off, but LH2 is so light and fluffy that this aircraft would weigh *less* than a fully fueled standard C-141.