i have a H-9 tcraft and it calls for a pull-pull rudder. i know these systems need to be tight therefore i will be using a bellcrank with it. would it be a good idea to install turnbuckles with it to keep the cables tight?
i was also thinking about replacing the system with 2 carbon fiber control rods instead to avoid possible rf interference.
Any comments appreciated.

I have used pull-pull on many models and you don't need a turnbuckle. Just get a dubro 4-40 pull-pull. It has everything you need. When you tighten it you don't want it so tight that it binds. You want more or less a dull twag when you pluck the string. not a tight high pitch twang. As far as RF interference goes you shouldn't have any problems what so ever. I have pull-pull in my 1/4 scale cap and the rec. ant. runs through a tube about 3 inches below it and I have never had a problem. Good luck and I hope this helps you.

Steve

Carbon fiber make a fairly good antenna and as such would not help with RF or EM interference.
Captianpitts is correct although, because pull-pull only works in tension, for the realitivly low loading on the Taylor 2-56 will be more than strong enough. The 4-40 systems only become ness when several servos are ganged. I can actually hang from the dubro 2-56 cable and I weigh about 180 pounds.

I agree with you 2-56 would be enough but to be IMAA legal all hardware has to be 4-40 or greater. That and there isn't much cost difference between the two

Steve

I've got a "Dons Hobbies" kevlar pull-pull on 2 of my giant planes and I really like them. Check 'em out.

Need Help!!!! Have .46 cap 580 w/saito .82,skywriter smoke pump and getting ready to change rudder setup from push rods to a Du-Bro 4-40 pull-pull system. I have two quest. @ this time. First,can the servo be offset? By this I mean off center. Secondly, I read you can use reg. horns as long as
the width is the same as the servo control. I do not like this idea because it defeats my purpose,I feel the horn system on this plane is its weak point. What suggestions are out there

The IMAA does NOT require 4-40 hardwre as I understand it... Just receive the following email from them regarding an upcoming meet...

Hello.
I am sending this email in response to a couple inquires regarding the use of 2-56 push rod material in an IMAA airplane and whether or not an airplane can fly at the 2006 IMAA Rally of the Giants event at the Castle air base in May 24-29.
Apparently some were informed that these planes would not be allowed to fly at this years event.
The IMAA Safety code states that the IMAA recommends the use of 4-40 push rod material for push rods in Giant Scale Airplanes. The use of 4-40 is however not mandatory.
Safety is #1 to the IMAA as it should be to everybody and in a majority of Giant Scale Airplanes 4-40 push rod material should be used, however there are some IMAA legal airplanes that do not need 4-40 sized push rod material and 2-56 sized material is fine and considered safe.

When we as pilots go to IMAA sanctioned events we sign the safety review form stating that our planes have been flown a minimum of 6 times and that everything is in safe working order (and more).

Please pass this information on to that those that you feel might go to Castle to fly at this years IMAA Rally of the Giants in Atwater, CA.
Thanks
Mike Brown
IMAA National Safety Officer