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A couple questions.

Old 04-15-2010, 07:34 PM
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lynx_strife
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Default A couple questions.

So bare with me here a little!! Got a few questions that I would love to get help with!

1.) Ihave a Thunder Tiger GP-40 with a OS Exhaust on it, I cant for the life of me get it tuned. The idle is a bit rough and it shakes a bit, when i give it some throttle it will sputter and die at 100%. It has a decent idle at around 55-60% throttle.
I can get it to do the "pinch the line and it will rev up then die" thing...but that is about it.
Ihave tried going off of what i seen on forums and youtube but I just don't get it all the way. So a retard proof way would be great!

1.A) When I was changing the idle setting needle thing, i noticed that i felt this oil/moisture coming off the prop. Also when i was testing the plane in vertical and inverted and what ever way i could think to put it, this oil/goop came out of the exhaust pipe

2.) Ok the stock covering on my plane makes me want to kill a kitten, how much of a chore is it to remove the covering and redo it? (Keep in mind I am a noob to that )

3.) Currently it is set up as a tricycle and would like to make it a tail dragger How hard would it be to make the change also for taking off and landing on well dirt roads what would be better?

I got this RTF package from a seller locally and would like to make it my own plane and get it running smooth as silk and clean up all the internals like the servos and RX and all that. Even remove the engine and take some solvent to it to make it look something other then a pile of dirt.

Thanks in advance!
Old 04-15-2010, 08:45 PM
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Lnewqban
 
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Default RE: A couple questions.

Typing the keyword "tucson" here:

http://www.rcuniverse.com/community/...uestTimeout=50

.............you can find some local RCU members, able to help you with a proper and safe engine tunning after you contact them by PM or e-mail.
Old 04-15-2010, 08:55 PM
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MinnFlyer
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Default RE: A couple questions.

1 - If it sputters and dies, have you adjusted the HIGH end needle valve? That's the big one sticking out of the side of the carb, or on the back of the engine.

1A - Are you SURE the oil was coming off the PROP? If it's overly rich, that would account for the "sputter and die" thing and it could be that it's so rich that fuel is spraying out of the carb and the prop is blowing it back. As for oil out of the muffler - totally normal, however the richer the mixture, the more oil you will get

2 - This depends. If the covering is Ultracote, you can heat it and easily peel it off. If it's MonoKote, it won't come off easy. As for re-covering. Watch these videos and see if it's something you want to tackle: [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=726]Covering Videos[/link]

3 - It depends on the plane. You'll have to add some plywood to the bottom of the fuse (reinforced with tri-stock). Locate the ply so the wheels will be centered on the Leading Edge of the wing. And you'll need to purchase an after-market tailwheel assembly that can be installed on a completed rudder.
Old 04-15-2010, 09:23 PM
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lynx_strife
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Default RE: A couple questions.

LNEWQBAN, I plan on trying to getting help from someone but I work over nights and have odd days off and sleep most of the day away. It is hard to find someone to help you at 6-9pm . And this is what forums are for!

Minnflyer you are my personal Jesus;

1. Is there a way to set it to like a factory setting of sorts? I cant find a factory manual anywhere to save my life. I need to find a dummys guide of sorts.

1.A there is some kind of liquid coming off the prop, it does smell like raw fuel.

2. Is there a way to tell if it is monokote or ultra? This seems like a older model it has a older radio/rx and servos.

3. I get to show off my noobiness! "Leading Edge of the wing" is that the CG point?


Old 04-15-2010, 09:47 PM
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Default RE: A couple questions.

I see; however, you never know others schedules.
I believe that nothing compares to local help.

My main concern is your safety around the propeller.

For cleaning the engine, I would try dawn power dissolver (from WalMart and alike stores).

Mike, could the rough tune and the fuel leak come from a expanded crankcase bushing?
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Old 04-15-2010, 09:49 PM
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MinnFlyer
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Default RE: A couple questions.

1 Close the needle valve and open it 2 1/2 turns (Count how many turns it takes to close it just for kicks)

2 Watch the videos and see if you want to tackle that before you remove the old. What plane is it? Certain manufacturers use certain coverings

3 "Leading edge" is the "Edge that leads the way" or in other words, it is the forward-most edge of the wing (opposite end = Traling Edge. These are often abbreviated here as LE & TE)

4 Now watch as I walk on water
Old 04-15-2010, 09:50 PM
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Default RE: A couple questions.

I guess your #3 really got to me.
No the LE of the wing is NOT the CG point. The CG point is somewhere in the range of 25% to 33% of the MAC. That stands for mean aerodynamic cord.
You really need someone locally to help you out here or your RC experience is going to be very short. Sorry but that is the truth of it.
Old 04-15-2010, 09:59 PM
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MinnFlyer
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Default RE: A couple questions.

Yes, as Mike and Juan said, you should really go to your local club and seek advice. We can only do so much over the internet. Someone can do you MUCH more good if they were right there with you.
Old 04-15-2010, 10:23 PM
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lynx_strife
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Default RE: A couple questions.

I am going to try and get with a local club, but with my days off and when i wake up are hard to set up meetings with people

I have tried for the life of me for 2 days well 1 day this week and 1 day a week ago to try and tune this engine to sound right and run smoother then it is right now. I am new to glow engines, I came from the electric prop flying so the dangers of finger+prop=zomgow? are not that much of a worry for me But I do thank you for the concern. I do plan on replacing the motor mount soon maybe i will make a engine test running stand thingy for it. So when i redo some of the inners of the plane I can bench test the engine of sorts. Anyone got plans to make a bench tester? I dont got a table right now so it will have to stand on its own lol sorry for being so much trouble. But thanks again!

My last question of the night, i am looking at the carb, and i can only find 2 needles on it. The big one off the carb and a smller one on the other side of it, and a hole on top that looks like a screw should go in it. I am guessing that a screw of some sort needs to go there?
Old 04-16-2010, 07:50 AM
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MinnFlyer
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Default RE: A couple questions.

This engine has an "Air Bleed" carb. This means that the low end is adjusted but regulating airflow as oppsed to fuel flow.

The carb should have 3 adjustments (See pic.) The Barrel Stop has nothing to do with the mixture. It holds the rotating barrel in place and also acts as a stop to prevent the barrel from rotating too much. This screw should never need adjusting.

The High Speed Needle is for adjusting the hight end. As you turn it in (Clockwise) it will reduce the flow of fuel which will "lean" the mixture.

The Low End adjustment is a screw that regulates airflow. This is only adjusted when the engine is at idle. When you turn it in, it reduces the flow of AIR which will "Richen" the mixture.
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Old 04-16-2010, 08:03 AM
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jester_s1
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Default RE: A couple questions.

It's possible that the engine is leaking out of the front, which would give you fuel in the prop. If that's the case you'll likely never get it tuned right until the leak is fixed. Put a big straw in the carb with it open and blow through it with the air bleed closed and the piston at bottom. If air comes out of the engine anywhere besides the muffler, you'll have to fix that before doing anything else.
Old 04-16-2010, 08:08 AM
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Default RE: A couple questions.

Make sure you wear your rubber ducky flotation device, just in case.
ORIGINAL: MinnFlyer

4 Now watch as I walk on water
Old 04-16-2010, 08:18 AM
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Default RE: A couple questions.


ORIGINAL: MinnFlyer

This engine has an ''Air Bleed'' carb. This means that the low end is adjusted but regulating airflow as oppsed to fuel flow.

The carb should have 3 adjustments (See pic.) The Barrel Stop has nothing to do with the mixture. It holds the rotating barrel in place and also acts as a stop to prevent the barrel from rotating too much. This screw should never need adjusting.

The High Speed Needle is for adjusting the hight end. As you turn it in (Clockwise) it will reduce the flow of fuel which will ''lean'' the mixture.

The Low End adjustment is a screw that regulates airflow. This is only adjusted when the engine is at idle. When you turn it in, it reduces the flow of AIR which will ''Richen'' the mixture.
Mike, I'm not a 2 stoke guy and I never had a plane with an air bleed carb but I heard that an air bleed tunes opposite that of standard carb. Clockwise will richen the engine. I'm probably wrong. As far as fuel coming of the prop, I think his engine is so rich fuel is spitting out of the carb.
Old 04-16-2010, 10:09 AM
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MinnFlyer
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Default RE: A couple questions.

Hey Robert, missed you at Toledo. Hope all went well for your daughter's happy day! (I always say, "You only get married for the first time once )

On an airbleed carb, only the low-end is air bleed. So the high end needle works like any other. The low end works "opposite the way a normal needle" works. Or actually, it works the same in that, as you turn it in, it restricts the flow - however, in this case, it is restricting the flow of AIR, not fuel.

So it could be considered "backward" in that as you turn the low end adjustment IN or Closed (since you are restricting the flow of AIR) the mixture will become rich.
Old 04-16-2010, 09:12 PM
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lynx_strife
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Default RE: A couple questions.

I found this website let me know what you think of this tuning how to?

http://www.rcgroups.com/forums/showthread.php?t=205602

Thanks for all you all have done for me!
Old 04-16-2010, 10:04 PM
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Default RE: A couple questions.

The post is fine, but does not show much about th efine tunning of the low end.
Also note that it describes a carb with low end needle, while yours is airbleed, as Mike has explained above.

Jester's advice above (Post #11) is very important in this case, since you don't know the history of the engine.

Check this article out:

http://www.*********.org/cars_eng-tuning.htm
Old 04-16-2010, 10:19 PM
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Default RE: A couple questions.


ORIGINAL: MinnFlyer

Hey Robert, missed you at Toledo. Hope all went well for your daughter's happy day! (I always say, ''You only get married for the first time once )

On an airbleed carb, only the low-end is air bleed. So the high end needle works like any other. The low end works ''opposite the way a normal needle'' works. Or actually, it works the same in that, as you turn it in, it restricts the flow - however, in this case, it is restricting the flow of AIR, not fuel.

So it could be considered ''backward'' in that as you turn the low end adjustment IN or Closed (since you are restricting the flow of AIR) the mixture will become rich.
Thanks for setting me straight Mike. The wedding went very well, everything was perfect including the weather but I couldn't help thinking about Toledo. Next year for sure.
Old 04-16-2010, 11:05 PM
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lynx_strife
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Default RE: A couple questions.

I just want the engine to run correct honestly, fine tuning came come down the road honestly..
Old 04-17-2010, 12:01 AM
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Default RE: A couple questions.


ORIGINAL: lynx_strife


1.A) When I was changing the idle setting needle thing, i noticed that i felt this oil/moisture coming off the prop. Also when i was testing the plane in vertical and inverted and what ever way i could think to put it, this oil/goop came out of the exhaust pipe

Oil out the exhaust is expected and required. We use castor oil because it is stable under high heat and so it ends up as unburned oil in the exhaust. Two-stroke engines need oil in with the fuel for proper lubrication.

Oil/fuel on the prop is another matter. That has to be blowing out through the front bearing seal [bad] or else burbling out from the carb [expected if overly rich] or some fitting or a hole in the fuel line [also bad].
Old 04-17-2010, 10:09 PM
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lynx_strife
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Default RE: A couple questions.


ORIGINAL: Charlie P.


ORIGINAL: lynx_strife


1.A) When I was changing the idle setting needle thing, i noticed that i felt this oil/moisture coming off the prop. Also when i was testing the plane in vertical and inverted and what ever way i could think to put it, this oil/goop came out of the exhaust pipe

Oil out the exhaust is expected and required. We use castor oil because it is stable under high heat and so it ends up as unburned oil in the exhaust. Two-stroke engines need oil in with the fuel for proper lubrication.

Oil/fuel on the prop is another matter. That has to be blowing out through the front bearing seal [bad] or else burbling out from the carb [expected if overly rich] or some fitting or a hole in the fuel line [also bad].
Inspected the front bearing seal and there is no leak. Fuel lines look good for what I can tell till they go into the main body. It smells like raw fuel when it get a nice coat of it on my arm I want to say it is from the carb. Iam going to set the carb to well how that how to i linked to this weekend let you all know... also the covering came off pretty simpel in my test areas on the plane let you know how that works out....

Old 04-18-2010, 10:01 PM
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Default RE: A couple questions.

What about the glow plug? Im a newbie to, and I dont know what happens when there old? Do they get fouled and stop working all together, or does the performance start to suffer first??

And what about the screw that's "missing" from his carb?

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