I have a G-26 on a 1/4 scale Ultimate. If I takeoff and climb out straight up, it will cut out for a split second after climbing about 100-150ft. It does this any time I takeoff after initially starting the engine. It doesn't matter if I run the engine is run an extended period of time on the ground or just start it up and go. The first takeoff after starting the engine always does this even if the engine had only been sitting long enough to re-fuel. The only way I can climb out vertically from takeoff is if I do a “scale” takeoff and one circuit around the field, land, line it up and take off again. If I do this, it will climb vertically until it is out of sight without the slightest hiccup.

This is a really strange one. Sure hope Ralph chimes in on this one as more than likely he will know just what's causing that to happen.

Karol

I have this happen to me frequently on my G62 powered Extra. I think it is because an air bubble gets into the fuel line while refueling. I refuel through a tee in the fuel pickup line. The only way out for the bubble is through the carburetor. The bubble goes through all at once when the airplanes nose is pointed up, because the fuel pickup port is in the front part of the regulator chamber in the carb. While the bubble is going through the carb, the engine is starved for fuel.

The problem should go away if refueled through a separate line to the tank, if this is indeed the cause .

Hope this helps.

Jerry

My g-26 does the same thing, I just have to remember not to do anything weird until I've flown at least one circuit around the field. The engine also does this if I roll inverted on takeoff, it never dies, just sounds like it has and then spools right back up and I am good for the rest of the flight. BTW, the only time my engine quits in flight is when the tank runs dry, so I have never considered this a serious problem even though my heart skips a beat if I don't expect this hiccup.

Mike

Sure sounds like you are tempting fate, as it's quite possible that one of these days the little hiccup is going to become more serious and the engine is going to quit in an ackward position... they always do []

Why not just trouble shoot and get it fixed.

Karol

It happens to me everytime I pull straight up from take off on my giant big stick with a g-26. It last for about a second so I have learned to trust it and I stay vertical and it runs back up and keeps on going.

Hmm....I would have guessed that the engines are not getting properly warmed up. Where's Ralph??? I haven't seen this problem with any of the three Zenoahs I have run.

It won't quit, the engine has been doing this since new and it's into the third season of running. It's just one of those quirky things that only happens at the begining of a flight, do a roll and it hiccups once then it's good to go.............

IT'S hapend with me, i discovered the the fule line in the tank need to changed , g-26 it's work fine now

Yeah I thought about it just being the engine needs to be warmed up when I first noticed it. But no I have ran the engine for awhile on the ground just to see and same thing happens.

Mine does the same thing installed on an Ultra Stick Lite. Usually it only happens on the first flight of the day but will do it almost any time I refuel. Never misses a beat after that. I just figured there is an air bubble in there somewhere and haven't worried about it. The engine is super dependable.

you fellas with engines that burb and go after fueling; Do you refuel through a 3rd line or do you have a 'T' in the carb supply line? The air in the fueling line has to go somewhere.

I have used both fuelling methods with my Zenoahs and have never experienced this sort of problem.

Karol

Ok...I changed out the tank and went to a 3 line setup....still have the same issue. I even tried it with different fuel filters in the line and a couple flights with no inline fuel filter. So at this point I think I can rule out an air bubble as the problem.

Can you duplicate the problem on the ground if you're holding the plane, and then point it vertical?

Yep.

Are all your engines running on the standard magneto ignition system or have any of them been converted to EI .... just a thought.

Karol

RCIgnitions conversion

All my Zenoahs that have been 'touched' by Ralph....nary a problem.

Karol0.

Is the engine installed upright or inverted? Can you fuel it and turn it inverted before starting to see if engine /carb aspect has any affect? (Like in a sling with restraints)

It is mounted inverted with a Mueller wrap-around header into a cannister muffler inside the fuse. The next thing I am going to try is swapping the exhaust a for a pitts style muffler to see if by chance my exhaust setup could somehow be causing this issue.

After fueling you might try holding plane vertical and giving a couple of extra choke on rotations to see if you can expel any vaporlocked air in the carb through the venturi jets. Aspect of the carb may be holding the air and it gets displaced slowly in normal flight.