After the nitro drill, I wanted to try and make similar projects with this kind of rc engines. Unfortunately, success didn’t come fast because I had to remake the whole build 3 times. I started with a Cox 049 (0.8cc) airplane engine which is very delicate concerning the fuel mixture as it requires at least 15% pure castor oil.
Modern fuel blends include a small percentage of this oil, with the rest being synthetic. This lead to its failure due to the overheating of the crankshaft, which rubbed against the crankcase walls naking it useless.The second engine I used was also for model airplanes, a O.S Max 10 RC (1.6cc) from the 70’s.
This one while it didn’t need special fuel blends, it was really difficult to start, not because it was stubborn, but of the way I made the tool to start: by spinning the flywheel with my thumb. It was almost impossible to make it start like this.
Only a few times the engine run, but for a few seconds. Then I thought I should use the kyosho gx-12 (2.1cc). It had a pull starter, which meant no more trouble with starting up the engine. It’s also more modern than the previous two engines, so it was the absolute winner of the 3./JohnnyQ90