I have a Magnum XL52RFS four stroke mounted inverted with OS type 4 glowplug. It runs, and idles fine, but will only start at about one quarter throttle. I also have the same engine, and plug right side up on anothere plane, and it will start at idle like normal. Is this just normal for an inverted install, or could there be a problem that I am overlooking? Any help or suggestions ?

Thanks Bob

Engines run better upright or on their side

Which is why you do not see me running inverted engines unless they are gasoline types - generally. Once in a while I fall for the looks of an inverted engine (P-40 1.40 size), but then I usually manage to sneak in a gasoline/spark fired engine.

I learned my lesson with my first and last Top Flite (George Aldrich design) Nobler control line competition stunt model. This was before the days of electric starters. It didn't take me long to figure out that flipping the model upside down was the answer for quick starts. Oh how I feel sad for that poor Enya .29 R/C engine. Back then the BX (base exchange) sold Fox Missile Mist fuel for $3.50 per gallon (25% nitro). The first thing that I did was to replace the stock cylinder head with the included high compression cylinder head and then fuel it up with Missile Mist. Then tune for max smoke (not exhaust). Somehow, that poor engine survived my break-in abuse and turned out to be a terrific engine, in spite of my best unknowing attempts at ruining it.

I realize that many folks have mastered the inverted starting routine and that they have absolutely no problem starting and running an inverted engine in the proper manner. However, it does take a lot of attention to detail (proper tank height) and the ability to sense what the engine needs to start in this position. I do it every once in a while, just to go through the drill of relearning how to do it. But I don't recommend it for anyone just getting going in the hobby. At least not right away. Unfortunately, with many of today's ARFs, you don't have much of a choice.

Maybe some of you experts, and we do have plenty, at starting/running inverted engines could write up a brief piece and post it as a sticky somewhere around here. I haven't done it enough to get my thoughts together. How about it guys?


Ed Cregger

LOL, buy a start stand(or build it "efficiently" out of PVC) and start the plane upside down. That eliminates the inversion being the issue. I've been flying motors inverted for a while now, pattern, 3D and scale, and have had few if any problems. Then again, they've pretty much all been O.S. Very Fuss Free motors.