ORIGINAL: nitroairplane
Diesels will only really take off if we have a shortage of glow and spark plugs or their materials for me this is frustrating as diesel cost a lot when compared with glow especially my tiny ones the most expensive engine per gram that i own is the Arne Hende special .1cc it was $250 for 10 grams.
Try flying in a country that bans alcohol in all its forms, looking at you Saudi Arabia.
And you may find that any custom made short production run engine is expensive regardless of its capacity.
Cheers.