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Help with throttle servo setup

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Help with throttle servo setup

Old 05-26-2008, 11:04 PM
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Cub Killer
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Default Help with throttle servo setup

Can someone please help me to understand how to set up the throttle servo in my H9 corsair.This is my first glow plane.What I need to know is........How to set things up so when I pull the throttle all the way back it will go to idle,but keep running.Then somehow,using trim I suppose kill the engine while closing the carb completely.Am I on the right track here?
I have a Dx7,seems like a wonderful radio.But the instructions are a little intense.I have 4 other planes.All electric.
This plane is almost ready to go.I put my own touches on it.Got rid of the JT on the tail and put a skull and cross bones.Will post pics when I get her smoking.
Thanks.
Old 05-27-2008, 12:17 AM
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KidVermin
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Default RE: Help with throttle servo setup

Cub,

All you can do is have a very small gap showing on the throttle barrel opening till you start it up and get the low end idle screw and main jet set. Then you can adjust the throttle trim on the Tx
Oops, forgot to mention you need to have a little servo closing movement left when the barrel is near closed. Using the outer most hole on the longest factory servo arm, you'll be able to have full open and close.
Old 05-27-2008, 03:18 AM
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ram3500-RCU
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Default RE: Help with throttle servo setup

First, back your barrel stop out till the barrel moves all the way down and closes off the hole, and then lock it with the jam nut. Now, when you set your travel, have the throttle trim all the way down. Start with the throttle barrel in it's center of travel and adjust the travel limits with your computer, in both directions from there. No binding should be present, and set the travel distance so the servo isn't bottoming out at either end, but just moving the barrel to it's limits. Now, you should be able to get a good idle by opening the trim up. The reverse will shut off the engine when you want. This is all assuming you have the low and mid range adjusted properly on the carburetor. If, at idle, the engine slowly falls off and dies, the engine is loading up and the low end is too rich. If it seems to idle but chokes when given throttle, the low end is a little too lean. You'll get it. It just takes a little patience. Once you get it, don't fool with it unless you change props, fuel, or there is a big climate change. These things sometimes require retuning a little. Many guys mess with their carburetors way too much. Let it warm up before assuming somethings is out of whack, and you will spend more time in the air.

I also give the high end a check for being too lean by holding the plane vertical at full throttle. It should not fall off significantly, if it does, it is too lean. Open it 1/8 and try again.
Old 05-27-2008, 05:43 AM
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kid chuckles
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Default RE: Help with throttle servo setup

Yes it is all by sight you just adjust at the servo and at the throttle arm. I start with my trim on radio in the center. That way you have movement up or down. Get it where it idles and then use trim down and if it dies your right if not then just looke inside carb and see what you need to adjust. Ususally if you get it within a 1/16 from close on idle the trim will close it off. Make sure your radio and servos are on and working to get things centered up before hand. Use a E-Z connector on servo arm and throttle linkage so you can move it easier. (one the linkage will slide thru). Close throttle and close the carb as if setting idle. Then use trim to close off completley. Depending on enginge sometimes this takes a bit to get right. Move one then the other now go back and move the other back again then the other you get it lol. Not real hard. I like mine dying before my trim bottoms out. Hope we helped some.
Old 05-27-2008, 11:31 AM
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BarracudaHockey
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Default RE: Help with throttle servo setup

In the system menu of the DX7 there's a function called THROTTLE RECOVERY

Set it to ACT or active for the model you're working on.

Then follow the excellent post by Ram3500

Now, when you land you hold the trim down until the engine shuts down. When you let go of the trim give it 1 push upwards. That will set your throttle trim back to its original position so you get the same idle setting every time w/o twiddling with the trim to get a good idle.
Old 05-28-2008, 01:39 AM
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Cub Killer
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Default RE: Help with throttle servo setup

Wow.
Thank you guys so much.I have a better idea now.I will be working on it this weekend.Excellent info.I should be annoying my neighbors soon Whilst I tune and break in.Ive got a couple of nitro trucks,but I'm told the planes are different.
Thanks Again...I will print this thread and take it out to the hanger with me.
Old 06-03-2008, 07:31 AM
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speedair
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Default RE: Help with throttle servo setup

there are two ways of doing this.

First way

Oppen the throttle stick and trim to full on your transmitter and on the engine untill the barrel is fully open connect the wire to the servo and throttle on the engine. Then pull the throttle back on yor transmitter with the throttle trim to the top. You should have about 1 mm of a gap showing where the barel is. This way you should be able to fully close the barel with the trim and throttle fully down which will stop the engine.

second way

close the throttle and trim to idle and the barrel closed connect it all up and you should be able to oppen it to full throttle

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