HYDROGEN POWERED FREIGHTER AIRCRAFT-THE FINAL RESULTS OF THE GREEN FREIGHTER PROJECT

摘要

This paper presents the results of the jointaircraft design project 'The Green Freighter'that dealt with the investigation of hydrogenfueledfreighter aircraft. This includedconventional as well as blended-wing-body(BWB) aircraft designs. Within the scope of theproject the Preliminary Aircraft Design andOptimization program PrADO was extendedand applied to analyses of conventional andunconventional freighter aircraft designs. Theinvestigations show that hydrogen as aviationfuel is feasible. Rising energy prices will makeair transport more expensive than today, buthydrogen is a potential alternative fuel thatkeeps air traffic possible even if low-pricedkerosene is no longer available. In addition, airtraffic could become more environmentallyfriendly. Hydrogen-fueled regional freighteraircraft have up to 5 % smaller maximum takeoffmasses and consume about 10 % less energythan the kerosene reference version despitetheir up to 7 % higher operating empty masses.The installation of large hydrogen tanks usingthe full fuselage cross section is significantlysuperior to an installation of removable tankswith smaller diameter. An unmanned freightercan use the cockpit volume for hydrogen storageand further helps to optimize the design. Theinvestigations of the hydrogen-fueled BWBdesigns show possible savings of about 6.5 % intake-off mass, which is predominantly due to a66.5 % lower fuel mass. The combination ofnecessary minimum aircraft size and low fuelmass causes a low wing loading. In effect, theBWB designs cannot make use of theirtheoretically very high aerodynamicperformance during cruise flight.