This is a BIG diesel model airplane engine. 4.85cc or .297ci. and American made in 1947. It is spinning a 14 x 6 propeller. I just acquired this engine. It was so gummed up that you couldn't turn the propeller. My first attempts at running it didn't work well. The manufacturer specified fuel made from 75% ether and 25% straight 20 weight motor oil. I mixed some of the 75/25 fuel and the engine would NOT run with that mix. I made some fuel today that was 70% ether and 30% Klotz Super Technoplate oil. To kick start it I primed with my "regular" home-made diesel fuel which is 30% ether; 40% kerosene, 30 oil (mostly castor oil with some Technoplate added) and about 1/2% cetane booster. The Drone fires immediately with the home brew diesel but its too hot for steady running. It took patience and MANY adjustments of the needle valve but I finally got a steady run of about 4 minutes before she ran out of fuel.