Howdy, first post here, but I fly and have followed this topic a bit The diesel aircraft engines coming out now use jet A1, though I believe they can use diesel or similar also. They are not as intolerant to alternate fuels as the avgas spark ignition aircraft engines.

The use of auto fuel was legally permitted in some low compression aircraft engines, but this permission specifically excluded any fuel with alcohol. Not only for the hygroscopic reason above, but due to aicraft fuel systems and tank sealants etc not being able to withstand the alcohol. The lower vapour pressure of auto fuel is also a problem inthe often antiquated aircraft fuel sytems contributing to vapour lock, which can be fatal if it happens at the wrong time!

This being said, there are aircraft flying on pure ethanol and blends around the world. Brazil has done a lot of work on it, and an aerobatic team flys on pure ethanol in the US. Obviously, they have done there homework.

cheers,

Grant