I have a 2 cycle inverted engine in a scale plane (as yet unflown). The convential wisdom is that it should have an on board glow driver.
I run a 4 stroke inverted without glow driver and it performs fine.
Logically, it seems that a 2 cycle should also run fine inverted. Those who have advised say that fuel will drown the glow plug during idle and kill the plug. However, an upright engine is inverted during the top of a loop (or other similar maneuvers, and when I pull power back to idle it doesn't quit. It seems that the valving process would keep excess fuel from drowning the plug.
Does anyone have first-hand experience with running a 2 cycle inverted with or without an on board glow driver?

Steve

I've personally ran a few two-strokes inverted. no problems - if you set up the tank correctly. Just make sure the tank is not tooooo high and you'll have no problems. Some current ARFs show mounting two-cycle engines inverted (GP Venus, Flip 3d, etc, etc).

It will run fine inverted and should be just fine without on-board glow.

The engines I've run inverted are OS 50SX and ST 51.

As swill said, make sure the centreline of the tank is in roughly the same position relative to the carb as it is with an upright engine. It's obvious when you think about it but for some reason tends to get over looked.

Fuel will NOT drown the plug at idle if you take more care in setting the mixture correctly. Use the pinch test and aim for a barely noticeable rise in revs. The only other precaution is to make sure the engine isn't flooded before starting.

I have never seen an inverted two stroke of any make or model fron worth a darn until i woke up. I run a OS 1.08 inverted on a larger P51. Ansolutely no problems on starting and flying. Trick is I lowered the tank to line up with the carb.

I have had some that will and some that won't.....

before you start drilling holes in the firewall of the new plane or cutting up the cowl, try this...


best thing to do is set it up on a stand upright or sideways and break it in. After it is broken in, adjust the needles and idle . When you are happy with the way it's running, re-mount it in the stand inverted with the tank in the exact location that it will be in when it is in the plane. re-adjust the mixture ....if it runs good now ,then you know for sure if it doesn't , you know that you will need to either mount it sideways/upright or go with on-board glow...

this method will eliminate any surprises

Thanks for the replies.
I had planned to do what was suggested: Recheck the centerline of carb with tank position, and adjust the engine idle on the ground. I have run five 4oz tanks through it on test stand. Engine started first flip, first time (91FX).
I will test long idle with several throttle-ups on the ground, in plane. If there are any problems, I won't fly until it works right.

Thanks again,
Steve

I have a GS 45 abc super tigre in my Venus 40..... i mounted it upside down at first and was not impressed had a hard time getting it running and let alone keeping it running...well i turned it at a 45 right side up since then have had no proglems with it at all Venus is my first low wing airplane and im VERY impressed
Note tho.....Pink is not my first choice of color you know what i mean.. Oliver
Winters,Ca

"hahaha the the plane doesnt know its to windy"

FWIW, I'm running a TT [pro 46 inverted in a Spacewalker ARF. No problems at all.