This is my first time setting up a pull pull system and I'm not really sure how to go about it. I was planning on using kevlar line, but in terms of how to run the line, what's all this about crossing the lines? How to tighten, how tight etc?

Any help would be appreciated!

Thx

David

Here are two companies that offer complete pull-pull setups that make it really easy to setup.

www.swbmfg.com

www.surelink.com

Either one of these are great products.

davey_flyer,

On most planes, crossing the pull-pull lines will give you a straighter shot at the horns. They need to be fairly tight, almost like a guitar string. Check them after each flight early on as they usually loosen up a bit and will need to be re-tightened. If this is on your Wildhare you probably should cross them, I just recently finished mine but waiting for spring to get it air-born. Feel free to PM me if you have any other questions with this build, I'd be glad to tell you what I've learned about it so far.

I second the swb manufacturing hardware recommendation. Scott at SWB makes a high quality product and has alot of knowledge of giant scale set-ups. I spoke to him at length about pull-pull setup and his feeling was that the wires should be kept at right angles and not crosses. If you viewed the wires, bellcrank and rudder horn from the top it would ideally form a rectangle. He usually cuts long slots in the side of the fuse about 1/8" high so the wire can pass through without binding. He sells kits that are set up for specific planes so alot of the guess work is taken out of the set-up. He can even custom design you a setup if your provide him with the necessary specs and dimensions. Give him a call he'll be more than happy to discuss his products.

I just finished putting a pull-pull rudder in a H9 33% Cap. I would suggest you keep it simple, avoid tiller arms (lower cost, lower weight, direct connection means less slop). Find a single ball bearing servo with enough torque and speed to do the job. For a 33% plane, the Hitec 5735 will do fine. I used an Airwild 3.0 inch aluminum servo arm amd Rocket City horns on the rudder, Sullivan 4-40 eyelets, 60lb plastic coated fishing leader for cable, and metal crimps made for the fishing leader. The cables run straight. The most important thing is the geometry needed to prevent the cables from tightening up as you move the rudder. Do a google search on the words "ackerman and pull-pull". This will explain correct geometry.

mine on my FC 35%

3D
Could you tell me where you got your tiller arm, thanks
art43

Giant Scale:

I noted in your post that long slots are cut in the fueselage for the pull/pull wires to exit the fuse. How long is long enough? It seems that 2 to 3 inches must be removed for the wire to have enough clearance.

Most planes I've seen have a hole with a piece of tube that the wire goes through.

I'm asking this as I'm building a 35% Edge and also finishing up a 27% cap. On the cap, I cut long slots but didn't like the look of them so I covered them when I covered the plane.

I would prefer to just install a hole with a plastic guide tube. On the other hand does that cause binding on th pull/pull wire?

Thanks.

Rich,
The length of the slot will depend on the specific installation. But the whole idea is for the cables form the rectangle geometry, they may be several inches long. But they only need to be slightly wider than the cable. I am not saying that this is the only way to install the cables, I have seen many types of installs. Some people cross the wires, some use pieces of tubeing at the exit point, some use long guide tubes, some use bellcranks that are fixed, some use floating bellcranks. Take alook at these pics to see what I mean.

Here's another pic

Rich,
I am not going to sit here and tell you one way is better than the other, everyone has their own methods. I trust what Scott at SWB tells me, he explained why some methods work and why some don't. I got on the topic of pull-pull's while discussing a system for my 50% CAP. Basically I needed a system to gang four servo's together. Knowing that the ideal cable orientation is a rectangle I can figure out the width of the rudder horn and servo arms I need to maintain the best geometry. I'm working with a fiberglass fuse so I'll just cut a long narrow slot out of the side to run the wire. If the slot is narrow enough it should barely be noticeable.

Thanks Giantscale.

Pictures are worth a thousand words. I'm real interested in the different ways to do this. All of the big planes I've had so far had the rudder servo's mounted in the tail.

I've also heard good things about SWB. I'll be checking them out.

Art43

The servo arms are AirWild, and the bellcrank is Nelson.

I also use the SWB setup.I definitely recomend a bellcrank.It takes all the load instead of putting the load on the servo bearing and causing premature wear.The SWB tray with the bellcrank alows you to set up the servos and linkages on the bench.I use Dubro lazer rod housings and the exit's to guide the cables through the plane.I'll try and get some pics if you want.
Mike.

3dbatixkid,
Who makes the yellow servo and battery wire keepers that are in your pic above? Also where did you get them? I have been trying to track these things down, but not knowing who manufactures them is making it kind of difficult.
Thanks, Travis

Here's a pic of the SWB setup.BTW I am pretty sure thos wire keepers are available from Dons hobbny shop,I believe they are from J-Tec.
Mike

lv2rcav8,
Thanks for the info on the wire keepers. I will check with Don's.
Travis