Popriv

TTPro .36
the manual says to open the high speed needle 2.5 turns as a starting point. Ok, thats fine.

Is there a "starting point" for the low speed screw?

If I remember correctly it says " turn 30 degrees at a time not to exceed 1 turn. " ??

When I was fooling around with it I kept track of my movements and could return to the original position.

With the help I've had its been moved.

Is there a "starting point for the low speed needle.

I'll ask for advice at the field on Saturday....

But I think new "dry" fuel will fix most of my problems.


Steve

da Rock

When there is a starting point, it's for a specific engine. And you'll find it in the engine's manual.

Very seldom is that given by a mfg. nowadays. Most of them do not have tolerances that deliver such repeatability. And it's often that they change things on an engine that would invalidate manuals that are that specific.

But you can count on one thing. A general rule for all engines that'll work for yours will work or not based on nothing other than chance.

BTW, the picture of the engine shows a carb with an airbleed setup.

da Rock

What does work with airbleed carbs is fairly simple. And it's based on logic.

An airbleed works through a hole. The "needle" is a screw. Its function is to block the hole somewhat.

The size of the hole is usually chosen with some care. You can use that idea to guess that the most effective adjustments are going to be when the screw is blocking about half the hole. This doesn't always work for every engine, because mfg's (especially ones making budget engines) have a tendency to use parts across a number of engines if they come close to working on them. whatever..........

A good place to start for the most probable airbleed starting position is done by looking into the hole. Turn the screw in or out until it blocks half the hole. Give that a shot.

BTW, airbleeds have a tendency to plug that hole, especially when they're not used for awhile. Fuel can gum up in there. Grass trash can also plug it. Sand, mud, blood, hair, teeth, eyes, etc can too....... Sometimes an engine that goes sour on low end and won't respond to adjusting simply has some crap in that hole.

BTW, airbleed adjustment is an art. It helps to do the adjusting with an eye on that hole. When the screw end is around the middle of the hole, each 30degree of adjustment usually produces a predictable change. When the screw end is almost out of the hole or has closed off a lot of it, each adjustment does very little.

Put her in the middle and go from there. Good luck, and try to keep the bugger clear.

Jetdesign

My Feedback: (8)

All my OS manuals (3) have a place where they talk about what happens when you lose track of your adjustments on the low needle - some are one full turn from where the screw is flush with the housing, and one is 3/4 turn open when the carb barrel is just at the fully closed position. I think this is stated after the basic tuning section, and after subsequent starting and tuning.

I understand your engine is not OS, but point is to check the manual and possibly in a place where you might not expect to find the information.

I'm not sure where to find TT manuals online - a bit tricky or I'd help look through it.

alfredbmor

The Thunder Tiger .36 Pro has not an air bleed carb. but it has a two needle valve carb.

http://www.thundertiger.com/product/9130.html

If for some reason you can not find the manufacturers original settings for the idle needle valve, I would suggest performing the following task:
Find some silicone fuel line and a common plastic syringe.
Take the carb. apart from the engine.
Attach the fuel line to the syringe and fill it with fresh glow fuel.
Attach the other end of the fuel line to the carb. nipple.
Open the high speed NV 2.5 turns.
Close the needle valve completely.
Using the arm of the throttle’s carb. close the barrel completely.
Apply a light force in the syringe, there should not be any fuel falling from the carb.
Open the idle needle valve one half turn.
Apply again force in the syringe, if the fuel begins to flow but it is hard on the syringe, open the idle needle valve one more half.
Perform the same task until the fuel flows lightly with not much pressure on the syringe.
Now assemble the carb. onto the engine, taking care of the O'ring.
Prepare the stuff to start the engine.
If the engine is new follow the break in info.
After the break in you can adjust the idle needle valve accordingly.

I hope this can be of help.

Regards:

Alfred.

da Rock

Boy the carb in this picture looks a lot like a airbleed carb. Smaller intake and that screw over on the other side going into a bulge that's characteristic of airbleeds..............

http://www3.towerhobbies.com/cgi-bin...&I=LXKF95&P=ML

Just as the latest advertisement on the ThunderTiger website shows what's obviously not an airbleed carb.

Good thing is, if your TT36 does have airbleed, you got some advice, and if it doesn't, you got some advice. Nice thing about forums, is you almost always have at least two opinions of how things are......

alfredbmor

Just like you said, great info regarding the airbleeders too. This definitively is not the case but is not bad to know more.

As per the manual, here is a link where you can find the carb. parts, sadly it is not much specific about the needle settings.

http://210.202.20.209/upload/2008-1/20081265108.pdf

Regards

Alfred.

JohnBuckner

My Feedback: (1)

If in fact Popriv's engine is a Thundertiger Pro in any of the displacements and it has not been modified then it indeed has a twin needle carbs not a bleeder.

On the link you posted just push for technical description and it even notes this is a twin needle carb.

da Rocks description of how to set up a bleeder midrange is quite good and can be usefull to folks with this type of carb as is alfredbmor's description for doing the same with a twin needle type.


I would like to ad the importance of knowing exactly what type of carb your engine has as there is a critical difference between the two:

Bleeder carbs are leaned by screwing low range screw out.

Twin needle carbs are leaned by screwing the low range needle in.

This applys to all current brands

The most common mistake for new folks with bleeder carbs is to screw the low range screw in to lean. Or try to adjust the midrange with the idle stop screw (wrong screw) which does nothing.

downunder

Another way to get a "close enough is good enough" initial idle setting is this:
1. Put a long length of tubing on the fuel nipple.
2. Set the barrel slightly open about where the engine would idle.
3. Open the main needle 2 or 3 turns or if you've had it running at full throttle then leave it there.
4. Go somewhere quiet.
5. Blow through the tubing and listen carefully for air going through the carb.
6. Adjust the idle needle in or out until there's just a faint hiss of air.

microsprint9

As for a starting point on the TT PRO.36 for the low speed i would say " as it came ", my Pro.36 low speed was bang on right out of the box and needed no adjustment, still after two years i have not moved it and it transions from idle to WOT cleanly with no hesitation.

Cyclic Hardover

My Feedback: (3)

When you beenat this a while. Factory settings mean nothing. Too many variables to throw it off. You need to get your own "factory setting" based on where you live. It's too easy. Just openup that high end the 2.5 turns. Open the carb barrel to a position that may be close to where ti should be at an idle (which isn't much).

Close the low end needle all the way. Now make sure your in a quiet area. Take a piece of fuel tubing and attach it to the carb nipple. Now at the same time, blow into the fuel tube and open the low end needle until you hear a hissing noisethere is your factory low end setting.

This does not mean it's dead on, just darn close and you need to adjust from their when you run it. There are other adjustment tricks and there is absolutely no reason why you cannot have a perfectly tuned engine

alfredbmor

It seems that it is also a great way to get close enough with the advantage that you are saving fuel (which now costs a leg and an arm for those who likes higher nitro contents).

Spacemonkey71

I had a DEMON of a time last weekend with this issue! The plane would start up, run fine, take off, fly (and fly FAST too! at 3/4 throttle it was like watching NASCAR - just REALLY fast up and down the field and lots of left hand turns ). I cut it to 1/3-1/2 to fly it "normal". Then, EVERY SINGLE TIME I LANDED, i'd swing it around, line it up, break start lowering the throttle to get it to drop altitude, cross the "threshhold" and cut the throttle to idle and then > a deafening silence! Dead-Stick! EVERY TIME! I brought it in just fine, it glides LONG so no problems there, but it was a PAIN!

I finally remembered the "low needle" and started monkeying around with that and it FINALLY got to where it wouldn't die on final approach! It was just aggravating (but I'm glad I didn't try to idle it outside of landing!!!)