earlwb

I do not remember any of the McCoy .35's going bad after a lean run. Like when the engine is just about to run out of fuel on the control line plane. But then we all used 100% castor oil back then. Do not run them with 100% synthetic oil though, the engines were designed for castor oil, plus they had a lapped piston in a steel sleeve and a bushed crankshaft, no ball bearings. But any brand engine tended to destroy their cylinder piston if you managed to run them lean too long like that. The lapped piston, bushed crank engines like lots of castor oil in the fuel, 20% minimum, 25% much better. Now there were lots of stories about how once you broke one in then it was wore out. But in actual use the engines lasted longer than that though.

As a kid the engines I had tended to wear out after several weekends of hard control line flying. We used to fly a lot, maybe ten flights a day. The engine would suck in dust and dirt, survive crashes and poor cleaning afterwards and so on. But the engines were cheap, something like one third to half the price of a Fox .35 engine at the time. As I recall it was like $7.50 for a McCoy .35 engine wheras a Fox .35 Stunt was going for $15.00, which was affordable when you are a kid mowing yards and delivering newspapers, etc. I could buy a new McCoy engine, some fuel, glow plugs, some comic books, and a root beer float or a milkshake with my money at the time. Usually the engine would eventually get to where you couldn't start it anymore as the compression was getting weaker over time. So since I had several engines, usually I could mix and match pistons and sleeves to get a tight one again to keep a engine running until I could afford getting a new engine. I wasn't the only one doing it either, everyone else was doing it too. I remember seeing estate sales where there was a box of old McCoy engine parts, but no complete engine, so others were mixing and matching too. it seemed at the time, that my memory recalls the McCoy .35 engine lasted about as long as the airplane it was on did. But Fox engine, barring a nasty crash, tended to last forever in comparison.

Now once a rich kid in the neighborhood got the flying bug watching us, and got Xmas, his dad gave him a deluxe control line plane setup all built up and RTF. The plane had a Fox .35 stunt engine on it. All of us kids were impressed, since it was a nice plane and all. But the kid refused our offers of help to fly the plane. But he did let us fire up the engine and adjust it for him. We ran a few tanks through it to help break it in some. Then he took the control handle stood in the middle and the handler let go of the plane. It went straight up and stalled and then shot straight down and crashed spectacularly. The kid threw down his handle and walked away and left everything. So I collected up all the stuff and wrecked plane. Later I went to his house to return the stuff and he said keep it, he didn't want it anymore. So I took it all home, repaired the airplane, cleaned the fox engine up and I flew that plane for ages after that. The Fox engine never wore out, it just kept on running and running and running.I had moved the engine from plane to plane, and it still worked OK. I still have that engine in the bottom of my engine box too, but I haven't tried to run it for many years now.