how tight should a pull pull system be?
 

I have a pull pull an my rudder in my new 50cc yak. This is my first pull pull so I'm not sure how they set up. How tight should I get the cables? I have them just tight enough to center the rudder now.

RE: how tight should a pull pull system be?
 

Ah, the question of the century: How tight it "tight"?

There's no really good way to explain it accurately - fortunately, you have a good amount of leeway.

The way I describe it is: They should be as tight as they can be without putting any stress on anything (Like the servo mount or the control horns)

RE: how tight should a pull pull system be?
 

Yes!
It depends on the gauge of cable you are using too. I think the stuff they give you in ARTF's is quite light and has a fair bit of stretch. It will tolerate being tightened so that there's no slack in the system and you can pick it like a guitar string. Now, if you can do THAT, then it's a bit too tight, but there shouldn't be a hint of sagging or kinking in the wire.

I have a Flair models Pull-pull compensator in one of my models, but I can't seem to see them any more. Basically, this separates the pull-pull from the servo, and has a spring tensioned arm. If you overdo the tension, it gets taken up in the spring. The servo links to it with a rod.

RE: how tight should a pull pull system be?
 

Also check it after a few flights. I've had a couple that stretched and loosened up.

RE: how tight should a pull pull system be?
 

Having used pull-pull on many large models as well as some small ones, I have found that two things lead to a successful pull-pull system. 1: have a slight bit of positive Ackerman built into the system (this is where the cable not being pulled will get slightly slack as the other cable is pulled off neutral and 2: just enough tension to keep any sag out of the line, keep it as loose as you can. I use pull-pull on both elevator and rudder as it is so much simpler, lighter and more reliable than push rods. It also makes split elevator hook up easier.