I don't believe gasoline engines will be going away anytime soon either! Gas may get to be so expensive that we can't afford it, and diesels may appear to be a cheaper alternative at first! But, I think diesel aircraft engines will prove to wear out quicker, be more expensive to repair, and won't be rebuildable as many times as gas engines in the real world. Aircraft diesels have a very long ways to go before they are nearly as affordable as gas engines in the long run. Besides, when diesel (jet-A) becomes the fuel of choice, the prices will skyrocket. Diesel used to be available only at truck stops, and was half the price of gasoline, until diesel powered cars became popular. Now it cost's nearly as much per gallon as gasoline (more in some areas at some times). You can't accurately compare cars and airplanes, but I understand and have worked on diesels in the automotive field. They are dependable and reliable, but expensive to repair. Aircraft diesel metalurgy has to be far and above anything in the automotive field to be as durable and reliable yet lightweight, and we aren't nearly there yet.
I'll burn 100% ethanol at some point if I have to and can get it approved, but I'm sticking with gas engines for the foreseeable future!
