I'm hopeing some experienced flyer's out there can help me solve my engine problem. I have a Hanger 9 twist with an OS 46 on it. Spinning a 10X6 prop. My problem is the engine dies during take off. I test run it before each flight opening it all the way and everything works fine. But on take off as I advance the throttle it dies about half way. This just started this evening. I had two really great fights with it then I couldn't get it up in the are again. This is a new engine with lest than 10 flights on it. I had two other guys tune it at the field two weeks ago and it seemed to have the same problem but it wouldn't die during take off.
What can I do to correct this?

Thanks for any help you can offer.

Hi RCLT40,

It may be that the clunk has moved to the front of the tank following storage or a rapid deceleration. Hold model vertical by prop and shake until you hear the clunk rattle freely at the back of the tank, then shake the model.

If this doesn't help you need to check the settings of the high and low speed needles and or check for air leaks. This is a process of elimination procedure and I suggest you have one of the more experienced flyers advise you as it is much easier to show that describe.

Godd Luck,

Colin

I would echo Campbec's suggestions, and I would also check the glow plug. My OS .46 gave me fits for an afternoon until I replaced the glow plug, and poof---no more problem. Don't use an idle-bar plug. It will cause problems with the OS engines. Hope this helps.

Two good ideas Colin:
I may go ahead and check that tonight before bed. And the air leak may also be an issue as I'm using a fuel dot. there might be some issues there.

Thanks again for your help


Kris

sparky:
Just put a new glow plug in the plane. The hobby shope dealer did as me what type to put but I wasn't sure. I said something about not running the engine to hot and gave me an A5.
And What's an Idle-bar plug?


Kris

A fuel dot should not cause any problems . That is why I use them over the "easy fueler". You may however have a fuel line/air leak problem somewhere else in the sytem. If a new plug doesn't cure it check all your fuel ines for the slightest pinhloe or crack. Even poor routing or improper fuel line lengths can cause this type of problem too. Make sure none of them are too short causing a sharp angle to the nipple as this will lean it out like a pinched line would. Too long of a fuel line can also cause a problem if it's extra length causes a bow in the fuel line creating an uphill battle for the fuel to draw through. I spend a frustrating afternoon finding these things out myself. After re-doing all the fuel lines at correct lengths with no binds or steep uphill routes, it finally ran just right again. Personally I find my OS 46 size engines like a hotter plug than the 5. I use OS#8 plugs with good success. Good luck.

G'day Mate.
First off a 10x6 is a 40 size prop, put an 11x6, & a OS 8 plug, to tune it slightly rich, run motor on ground, at full throttle, slowly turn high speed needle in, until the motor starts to sag, wind needle out, noting how far you turn it, until it starts to sag on the rich side, this is your tuning range, then turn it in, until it runs at a clean 2 stroke sound, this will only be a few clicks, & leave it there, but make sure you have no air leaks first. Hold the plane nose high & it should gain some revs, this is spot on tuned.

If you guys must have seen the spacing between the firewall and the engine on a H9 Twist. There isn't much room there so a bend might be the issue. Also because I'm using a fule dot I need to clamp of the line runing from the Tee to the cab on my 46 so when I fule it up it won't flud the carb. So, there the possiblity I may have a hole in it from doing that.

Normally when a fuel dot is used a 3-line setup will be used on the fuel tank. This way you won't have to block the line to the carb. One line is your normal pickup line going to the carb, the second line is your vent line from the muffler, and the third line is used as your fill line. Make sure you put a clunk on the fill line so that you can drain the fuel tank too.

Hope this helps

Ken

Yes you may. I use the fuel dots as I stated before. I do not however use any T's. I set up a 3 line fuel tank system. 1 line for a vent which goes to the nipple on the pipe to pressurize the tank. The next line is the fuel feed line to the carb with a clunk on it (make sure you have a good straight length to the carb). & the 3rd line is my fill line going from the fuel dot to the tank which also has a clunk on it. No T's means each fuel line is independent of the others & no flooding of the carb when fueling. When I have it set up like this properly(no kinks or sharp bends) anywhere, it works flawlessly.

I too agree that an APC 11X6 prop is the sweet spot for a .46 engine. It will give you great pulling power, good top end speed & won't over-rev the engine. I hope you hear something in here that will help you.

Sounds to me like the engine is not properly tuned up.

Look at the drawing in post #9 and you will notice the short section of hard tubing. This is used to prevent the internal pickup line from being able to double up and get back to the front of the tank. If your clunk has flipped forward (hard landing or careless handling) the engine should die when you hold the nose up for a little while.

I agree with Alan. I had the same problem with my OS46LA. Went to the 11x6 prop and problem solved.
Bigger engines need bigger props, they act as a flywheel.
KW_Counter

Yes, you are right. Someone else on this form said that same thing. I wonder if this is the cause of my other problems?

This sounds like a possible answer to my issue. I did have some tuff landings. I did however, take the advise give in in this thread about holding the plane noes up and shaking it. I could here the clunk rattle about. So I think it extened now. But it may not stay that way. The tank came pre built (ie the clunk was already installed) so I didn't inspect to see how it was installed. Also, I don't think it has a spot for a third line but that's easy to find out. I can easly remove the tank and see.

Oh! I also wanted to say that I checked for leaks this evening. I clamped off one end of the fuel line (between the carb and the neadel valve) and blue into the other end. It seems as there were not any leaks.
I guess my next move is to remove the tank and inspect it to see if I can add the fill line as a third connection.

Thanks for everyones help and if anybody has more ideas please pass them one.
I'll try and report on my progress soon

I just had to check tonight before heading to bed. I pulled the tank and there is a spot for adding a third line. Just need to get the tube to put in there. I notice on you example that there is a secion of metal tubing about half way to the clunk. I would guess that this is what keeps it from swinging forward. Also, It seems that the fule dot line also connects to the clunk. Does it really need to have another clunk. Or one that can do two lines? I was hoping that I could just bend the pipe in an upward pattern like the pressure line.


Kris

The 2nd clunk is to hold that fill line at the bottom of your tank so it is easier to defuel at the end of the day.

No, you don't have to have a clunk on the 3rd/fill line. But as it was said above, you won't be able to pump out the tank if you don't have a clunk on it.

Ken

Sure you will, if you plumb it like this:

this looks like the cheaper way to go. I was going to run the fill line all the way to the back of the tank but this works as well.




Hockey fan? I was noticing your logo...

It works well. People who run boats have been using this setup for years, without the clunk. When you're emptying the tank at the end of the day, jut tip the nose of the plane down a bit.
Good guess! And you?

About the only sport I'll watch on TV. Last year a feeder team setup shop in town and it's drawing big crowds.
Last year they didn't win many games but it's always good fun.

Thanks for you help on the tank