how dose one figure which hole to use to put in my control rod hole#1
                                                                                         hole #2
                                                                                         hole #3
and then in my bell crank same thing.
please help

roger

If you're uncertain, use the maximum output hole on the bellcrank, this will give you a lot of pushrod movement.

Then you can use as tall a control horn as needed to get the degrees of movement you need.  The BC is built into the wing, so you only get one easy shot at that decision.  Assuming the control horn is external, you can fiddle with that end later. 

If you "go stingy" at the bellcrank and don't have enough throw, there's no easy way to get it back.

Got up this mornin', went to fly me some stunt.
Got up this mornin', went to fly me some stunt.
But my control horn wore out, and my plane commenced to hunt.

I think Howard needs to tie dye his silkspan..............

My baby she told me, "Your squares make me wanna barf."
My baby she told me, "Your squares make me wanna barf."
I been so 'buked and scorned, I might go buy myself an ARF.

Go Howard! Some of us are with you... 

Gonna play me the blues, ain't articulate 'nough for hip-hop or rap.
Gonna play me the blues, ain't articulate 'nough for hip-hop or rap.
But I'll fly me some stunt with my articulated flap. 

Blues later. Back to the original question. Consider your basic math skills from Jr. High. Specifically, Ratios!

Ideally, you'd like to have at least 3" spacing at the handle, with 4" being better. If you use a 4" bellcrank and a 4" handle spacing, you've got 1:1 at this stage. Then, take a look at your elevator horn selection. Say you have a 1" horn you can use. If your 4" bellcrank also has a hole at 1", and you used it, you'd still have 1:1 control ratio. That means you'd get 10 degrees elevator for 10 degrees of wrist motion.

This would probably too much (sensitive). So, look for a hole in the BC at .625"/.75" or somewhere in there.  If your model has flaps, then you might have a longer flap horn, say 1.25" to the top hole. With a bit of calculating, you can figure out what you'll get with the various holes on the bellcrank. Then, there's the flap to elevator horn hole selection...well, if the next lower hole on the flap horn is at 1", then if you used that 1" elevator horn, you'd have 1:1 flap/elevator, which is fine if your model is on the 'stout' side. You'd want to use a longer elev. horn for a heavy model, and a shorter horn for a lighter model. Best bet is to use an adjustable horn on the elevator, of course.

The main thing to remember is that you can actually calculate and predict the results pretty well, and if you find a set of ratios you like, sticking with it makes things easier with new models. So, keep notes on your control system's ratios, make modifications in a logical way, and when you find something that suits you, stick with it.    Steve

We was strummin and Hummin the stunt flier blues
We was strummin and Hummin the stunt flier blues
We sat around singin headlines from stunt news

Oh baby.....

We got , PW & Howie there's  Billy and Bobby
We got , PW & Howie there's  Billy and Bobby
We're all hammered and silly in a' lobby....

Sing it with me now.....

and that my stunt flying friends is how
and that my stunt flying friends is how
the stunt flying blues EEENNNDSSS!!!!!

Thank you, thank you very much we're in the Crystal room 'till Saturday.  Tell your friends the "Cross border, crossed lines, Heavy weight blues brothers, Dr. Howie "Blues" Rush, and "Downtown" Donnie B Perry"  Are in town and ready to rock!

You are getting some conflicting advice.  I'd recommend looking at your old statics book.  For a given control surface hinge moment, the farther from the axis the pushrod is, the less the force on the pushrod and the less the effect of control looseness (verse 2 above), which is a problem if you don't use ball links (verse 1 above). You are more likely to be size-limited on the bellcrank than the control horns, so I think I'd use big horns and set the axis-to-pushrod-hole distance an the bellcrank to allow full bellcrank movement for full control surface movement, which would minimize differential line tension, hence the difference in handle movement required for a given control deflection as a function of airspeed.  In my case, I have a 700-square-inch stunter with 4" bellcrank, flap horn holes 1.5" and 1" from the axis, and elevator horn hole .95" from the axis.  Flying it in the wind in Muncie on .015" 7-strand cables, I had to guess how much handle deflection to use for each square corner, resulting in verse 3 above.   One remedy was to use balance tabs on the flaps (verse 4 above).  Col. McClain has asked me to write a short monograph on the tabs for Stunt News, which I may do as soon as I figure out the mechanics of line bowing and stretch, at which I'm not going to look until I finish my new airplane:

Gotta go downstairs now and lay on some dope.
Gotta go downstairs now and lay on some dope.
Gonna finish my plane for the Nats, I hope.

Rog,

I don't sweat this thing, because I design and build my own bellcranks and horns to fit each individual model. (That is possible, btw. You just need an approach that you understand and trust...)

I DO check my analysis numbers against available parts, so if any fit I can save some work. Never seems to happen. I've been pleased with all the pieces I've knocked out for my stuff, but that's just me. I enjoy doing that side of things, so I'm probably easy to please...

To your specific question, you have a lot of good advice.