Pull Pull Rudder - Rods or Cable?
08-11-2004, 01:46 PM
#1
Thread Starter
Pull Pull Rudder - Rods or Cable?
I am getting ready to install my first pull-pull system on the rudder on my Ultra Stick Lite. I have searched RCU and read many threads on the pull pull systems and how they are set up. My question is really whether I gain/lose anything between using push rods or cables. I know that weight is probably a factor, but with the US Lite and a G-26 on the front, adding a few oz's of weight on the tail will probably be a benefit anyway. I plan to mount the servo (Hitec 635HB) on the upper part of the fuse tail and connect it to the rudder with a single servo arm. I could use a cable, but did use a pull pull on my Magic Extra using pushrods rather than a cable hook up. Any recommendations or input would be appreciated. Since I haven't started, I am open to either method. I won't be running the cable/or rods through the fuse, so it will be a pretty basic install.
08-11-2004, 02:54 PM
#3
Senior Member
RE: Pull Pull Rudder - Rods or Cable?
Cables because, if there is the slightest error in having the pivot points ahead of or behind the hinge line, the rigid rods will cause excessive servo current. Using cables, if you set it up so that the non pulling line goes slightly slack at extreme positions, you will still have positive control and no servo problems.
08-11-2004, 03:34 PM
#4
Thread Starter
RE: Pull Pull Rudder - Rods or Cable?
If they are set right on the hinge line, wouldn't both cable's keep the same tension especially if I come right from the servo horn to the rudder control horns?
08-11-2004, 05:40 PM
#5
Senior Member
Join Date: Nov 2002
Location: Crete,
IL
Posts: 2,251
Likes: 0
Received 0 Likes
on
0 Posts
RE: Pull Pull Rudder - Rods or Cable?
I agree with post #3. Cables will be much easier to set up as not many pull-pull systems are 100% perfect geometry. Using rods would require everything to be perfect and really have no feasible advantage over cable.
08-12-2004, 07:58 AM
#6
Thread Starter
RE: Pull Pull Rudder - Rods or Cable?
I did some more reading and research on the pull pull questions I have and decided to go the cable route. I also stopped by my LHS yesterday and took a look at a set up that the owner uses on his pattern plane. The set up looks clean, light, and uncomplicated. I also read the thread on RCU that talks about using the "ackerman" technique of setting the control horn just a little behind the hinge line and will incorporate that in mine as well. Will start assembling tonight .....as soon as I clean off my workbench. Yeah, it's a tough job, but someone has to do it. Haven't seen the top for quite a while now.
