company called PAW makes diesels. also check MECA web site & Davis Diesel. both make conversion kits for glow to diesel. diesels can run much longer on a given amount of fuel, swing bigger props than the same glow size & ( once started ) are fairly easy to adjust. if you have limited space to install a powerplant & need to move a large prop, diesels will work well.
they are not popular in the US for a number of reasons but some negatives are; fuel is harder to obtain contains ether & is very evaporative , neccesitating storage in small quantities. Diesels STINK when they run-- bad, in many peoples opinion. they also throw out a lot of very nasty exhaust that eats all but the most durable finishes, also you will need different fuel lines in EVERYTHING as glow fuel tubing is not compatible. you will need to clean the engine interior after a full season of running.