1212. Some Ideas for Layout and Design of Aircraft Using Liquid Hydrogen Fuel

Paper

Abstract

This paper was prepared in view of the coming fuel crisis and general energy shortage to get a first idea of what the use of liquid hydrogen for aircraft could mean. Other fuels as LH2 for fossils fuel replacement are possible; however, it was felt by the author that there is no other fuel working so ideally in a non-toxic ‘closed cycle’ which is important for further life support on earth. A literature study showed no severe difficulties in using liquid hydrogen successfully as an aircraft fuel. Even flight tests have been carried out by NACA in 1956. There is a lot of information available for special features of tank and fuel system design, fuel cost estimations, and preliminary aircraft layouts including weight breakdowns. However, there was no estimation available of the economics of LH2-powered airliners flying in the subsonic speed range. Therefore, some estimations for such types of aircraft were carried out by rough hand methods, showing so drastically improved payload/take-off weight ratios that even at today’s US-hydrogen prices the LH2-aircraft would have no cost penalty in relation to an JP-fueled aircraft taking into account current fuel prices. Even more drastic improvements came out for VTOL-aircraft with LH2 fuel due to their more critical weight sensitivity, and the VTOL-range as a major disadvantage of VTOL-aircraft up to now could be increased very effectively.
As a more general conclusion, the whole state of the art of optimum aircraft layout and design has to be reviewed if LH2 fuel for aircraft is considered.