I'm hooking up a Pull-pull rudder system and my question is when do you use a "straight" rudder servo control horn or one of those "SWB" ones with the curved ends?

how much of a space is the rudder horns seperated? this is going to help make the call

They are about 3.5 inches apart, hole-2-hole

yes i would go with the 4" swb for the servo

3D,

Is this for the YAK? I used the SWB 4" with the curved ends on mine, works fine. Also, cross the cables. Love the SWB servo arms, put them on all around on my KMP Yak. 1 1/2" on ailerons and elevators, and 4" on rudder. I've had other arms vibrate loose, even with loctite, not these! Hurry up and get that thing done!!!!

Tim

Hello Guns:

I've read a couple of times about crossing cables in pull-pull configurations.

Could you please explain why?

I'm not doubting that it's the correct thing to, I would just like to understand. I will be setting up an ARF soon with a pull-pull cable on the rudder and I would like to do "the right thing".

Thanks.

Bye, Ian

You only have to cross the lines if the width of the control horn on the servo is "different" from the width of the control horns at the rudder. However, since they end up being different about 80% of the time, its probably just best to count on them having to cross.

I already bought the other servo horns for everything else..... Hmm, ok, maybe I'll exchange those as well since I have to exchange the other ones. Since they cost more, they should be fine with that I would think.

And, yes, I would be ready by next weekend except now I have to wait for control horns to go back and forth in the mail...so probably 2 weekends from now.

3D,

Other servo arms work fine, I just really like having the double retention system on the SWB arms. I went with the 1 1/2" arms just because I went "overkill" on the servos (HT-5985s at 6V) and wanted the extreme throws. 1 1/4" arms will work fine also. I didn't use the control horns that came with the plane, I used Dubro HD horns, I prefer them on the big planes. My rudder horns are 4" apart, but the crossed cables gave me better throws without any binding or rubbing. I am contemplating buying another YAK just to have in the closet in case I screw this one up. It is by far the best flying plane I own! 16lbs even!

Tim

Ok, I bought the 1.5" but they seem overkill.... Didn't you have to reduce the throw in the radio to compensate for them? I was going to exchange them for the 1.25" in the SWB. I really don't want to gunk up my servos with locktite.

OK - I'll play ignorant. What's "SWB" and where can I learn about them? []

I'm not sure your allowed to post urls on RCU...they got more rules than the government.
Put check troybuiltmodels dot com.

http://troybuiltmodels.com/servoarms.htm