Inverted 2s operation?
 

Does operating an engine inverted require any different settings than if it is tweaked "right side up"? I'm guessing generally the carb would be a lower than the tank. Running a Pico .46 in an Altech "Tamecat". Runs fine everywhere but has a tendency to "flameout" on climbout? If I turn the plane up-side down and tweak the settings, I am more likely to cure the problem or make it worse? What about 4 s's,any difference there. Maybe there's an older thread that addresses this issue.

Inverted 2s operation?
 

Hello!
Anytime you run a glow engine inverted you could expect a little more problem than if you run it with the cylinder up.....That´s because the glowplug sometimes get a direct hit of cold fuel(and oil).It is always bet to mount any glow engine with the cylinder up or tilted 45 degrees to its side.

Regards!
Jan K
Sweden

Inverted 2s operation?
 

If your fuel tank is set at the right level it makes no difference which way your 2-strike is oriented. But you have to remember that the fuel tank level that's best for an upright engine is not the same as for an inverted engine. Best method is trial and error. I set up my old Thundertiger Champion 45L by flipping the plane upside down and right side up until there was virtually no RPM change either way and never had a flameout. Only took about 45 minutes.

Not sure about 4-strokes, though. No experience with them being inverted.

inverted
 

Good suggestion Chuck, I'll give that a try. I can understand a dose of fuel "killing" the glow plug on transition, but not so much on climbout.

Inverted 2s operation?
 

So long as the centre line of the tank is mounted in the same relative position to the carby the engine doesn't give a hoot which way up it is. And if it's tuned properly (especially at idle) there's no way you'll douse the plug with all those bits thrashing up and down several thousand times a minute :D

Inverted 2s operation?
 

Hi wsmaley,

i used an inverted two stroke most of last year. Was a lot of trouble untill i leaned out the idle enough that it didn't load up. The flame out on climb out kinda sounds like you are pushing the high speed needle a little too lean. if you mean climb out on take off this is likely to be because once you pick up air speed, the prop spins a bit faster and the air enters the carb a little faster than when adjusting on the ground, so it leans out. If you mean climb out as in you are zooming along and you point the nose up and it dies, the tank might be too far back or too long and you are pushing the needle too lean for that kind of flying.

Tank height is really quite important. If you have it right, the engine will run the same when you fly inverted. Some two strokes seem to be more sensitive to tank height than ohers. The ones i have had most trouble with is the Tower 46 and others that have the big expansion muffler without baffles. They don't produce much pressure for the tank. Just installed a Macs muffler on one last week. didn't gain or loose any RPM, but I had to turn the high speed needle in about a full turn, to compensate for the increased tank pressure. (?) Higher tank pressure = consistent fuel flow. so far it seems to have done the trick.

I have an inverted 4 stroke in an aresti, works Fine, but my guess is it is vulverable to the same problems as a 2 stroke.
one advantage of the four stroker is the plug enters the the cylinder at a 45 degree angle at the side of the head, instead of straight up from the bottom of a funnel (dome of head).

my two cents worth, refunds available on request.

best of luck.

Shmo

2s and mufflers
 

Some good points to check Shmo. Had occasion the other day to want to fly a new plane/engine combo. We tweaked the engine and thought we had everything just right and all of a sudden the engine kept dying on throttle up- The muffler had moved a little and pinched the pressure line! That was a S.T. 61 and a slight kink shut it down. Yes, by climbout I meant take-off. Twice I had to rebuild the front end when it stalled at low altitude. I asked about 4s's because I've spent several years scratching a Fiesler Storch with inverted Saito 80 4s. Despite their supposedly fantastic STOL capability, I hear they are definitly not a power off airplane. Bill S.