I've got one mounted to an early '70's Senior Falcon and even though it wasn't started up in at LEAST 10 years, with a little priming and a touch of tuning (no taking apart or anything - just cylcying some fuel through it) it JUMPED to life and pulled like an OX with an 11x8 prop! For comparison, I've also got an OS Max FP .60 size, and even though it's almost new (it's been broken in and flown for maybe a year) it seems to pull about HALF as hard.

It's an EXCELLENT engine that is the closest thing to "bullet proof" you can have! You've got a REAL treasure there! The Webra website (do a google on Webra homepage) has a manual (look for the "english" one) it has some charts in it that will tell you what size props are good for it in it's operating range. It's a "generic" manual for all Webra engines, but it covers this size/model well enough to get the right glow plug, prop, and fuel mix (you can run anything from 5% nitro to 15% nitro -> don't run anything past 15% b/c of the compression or you'll have to "shim" the head to give it some room. According to the manual, Webra engines don't even really need Nitro at all to run! When you increase the nitro % you have to decrease the methanol %; don't monkey with the oil ratio!

The Webra 10ccm works out to a 0.610 size engine. Yes, it's a bit on the heavy side - it's a beefy engine; but it pulls so danged hard, it doesn't seem to matter. And a little weight up from (especially for a trainer) is NOT a bad thing at all. If you're planning on strapping it to something else, go for it! It will pull verticle like it's been shot out of a bazooka! (assuming the plane your flying isn't a total brick ). If you strap that baby to something like a Great Planes "Das Ugly Stik 60" it will fly like a cat with it's tail on fire and do ANYTHING you want it to (and probably a couple of things you don't )!!! In other words, he's going to have an absolute BALL with it!