Control Set Up

[Gary Anderson]

Hi guys,

Is this picture correct? Would you have very much movement of the controls with the push rod in the first hole? Would it be too close or create to much resistance at the control horn with the push rod being so close to the elevator? Wouldn't that make the controls really to quick? I have always used the furthest hole on the control horns. I have always used the furthest hole on the bellcrank.  Most mine end up with a 33 degree deflection on my flaps and elevators. Could have more degree movement but I stop my bellcrank around a one inch movement. Always been afraid if I let the bellcrank go too far it would hang up. Would appreciate any and all input, thank you Gary

[Jim Thomerson]

That looks about right; how I set them up, more or less.  The setup shown is the least sensitive. If you move the bellcrank hole out, you make your controls MORE sensitive.  If you move your horn hole in, you make your control MORE sensitive. I am happy with 20-25 degrees deflection either way. 

[L0U CRANE]

Right, Gary,

Looks about right, as Jim said.

I don't like to build limits on the controls. We can keep them from hanging up while building by checking their full range of motion and clearing space wherever needed.

I usually build to clear about 60° bellcrank rotation each way, just to make sure nothing will snag. Also, that much motion must be free without excess space between pushrods and horns - vibration can make space like that chew out the fit to where things get sloppy, or worse, break...

Limits on how much angle to use in the air can be helped by adjusting the space between lines at the handle. Closer together shifts the lines less, and line shift is what turns the bellcrank... Longer from the hinge on the elevator horn also 'slows' response, and gives you more torque to turn the elevator against air loads. In your sketch of the elevator horn, it looks like the middle hole is about twice as far from the elevator hing as the iner hole, and the outer hole is about that distance further out. So, yes, it takes twice as much force to use the inner hole as with the middle hole. Three times as much if you compare the force needed at the innermost hole with what the outermost hole needs - and if my SWAG about the horn hole distances from the hinge is anywhere close...

HOWEVER, we have the full force of line pull* to overcome the airloads, and the differences shouldn't be noticeable from the handle.
(* - if airloads require, we could turn the handle so as to pull one line hard enough that the entire CF is on that line. Seldom seen. Not a thing to worry about.)

In our cars, the steering wheel can be turned enough to make a tight U-turn, but we don't turn the wheel that far in any other situation that that. We steer just as much as needed. Flying CL is like that - we 'steer' only enough to do what we need, and we can finesse it, too.