I am building a Sopwith Pup and i am not understanding fully the pull pull setups.

I want to set up Rudder and Elevator on a Pull Pull system. so here goes the Q's

1. Where in relation to the control surface do the servos need to be located, are they to be directly centered in the Fuse?

2. If they are to be centered, How do you stagger the servos so that the pull wires do not interfere with the opposing servo? Does 1 servo need to be mounted in a higher position?

3. I can understand a regular pull pull system on the elevator using 1 control horn per side, But how does the top control horn work that ive seen people had wires hook to top of the elevator? wouldnt that cancel out the pull if the 2 wires ran from the same side of the servo arm? OR are they dummy wires for visual purposes??

Any help on these setups would be alot of help and very appreciated

Usually it's pull pull on the rudder and a y pushrod or dual servos for the elevator. Yes you stagger the servos on the center line of the model by height. there are all of ways to do it.

1 position the elevator servo 90 degrees to the rudder servo so the control horns and a straight shot to the elevator. top horn to the top of the elevator the bottom to the bottom.

2 have the control rod off the servo connected to a cam or spool that pivots in line with the elevator. this can be done 3 ways
regular pull pull with a torque rod running from one elevator to the other.
two servos with separate cables hooked top and bottom to each elevator.
1 servo hooked to a double cam.
the one model I used a pull pull on the elevator, I welded a metal control horn to the center of the elevator torque rod run down the center of the model with the servo laying on its side in relation to the rudder. The rudder sat back and slightly higher than the elevator. wish I had some pic but that was a model I build for someone else. seriously the pull pull on the elevator just isn't worth the trouble with the exception of profile jobs were you can get to everything and its a cinch to mount the servo or your entering a masters competition

Can i used standard Futaba S3004 Servos for these setups or do they require any kind of high torque servo?

The speed and torque of a servo in your airplane is determined by a couple of factors...
1 speed of the airplane...as this is a Sopwith Pup not a factor
2 weight of the aircraft
3 size of the control surface....you don't want to run a standard servo when you're throwing a barn door into the slip stream at 100 MPH.

Your instructions should give you an idea what servo is required....

I have pull/pull set up in my BUSA Pup, I can take some pics when I get home. I have the rudder and Elev servos up front near the tank (for cg) with a pushrod going to a crank. The elev crank is behind the cockpit and the rudder crank is under the cockpit.

Pay close attention to your bell crank geometry. If your bell crank holes line up with the hinge line, then the servo bell crank should line up with the servo pivot point. If its 1/8" behind the hinge line, then the servo holes should be 1/8" behind the servo pivot point. And so on. If they are not the same you leave yourself open to a line going slack. To some its not a problem, I'm just more annal about it. I also dont use bushinged servos since I keep a fair amount of tension on the lines. You dont have to be guitar string tight, just taught.
Edwin

One of the better sites for learning about pull-pull is Alan's hobbies, go to http://homepages.ihug.co.nz/~atong/ and scroll down to pull-pull. Once you understand the term Ackerman (covered in the suggested site) and do a couple installations, you will probably always use pull-pull on the rudder and elevator on your planes. If you always use a little bit of positive Ackerman you can do a lot with pull-pull including routing lines around obstructions, having easily adjustable/variable throws and many other features with very little weight and great reliability. If you can get a copy of an old May 1993 issue of Model Airplane News, there is a good article on how to make your own Giant-Scale Pull-Pull system easily and inexpensively.

Rodney, where were you about four or five days ago? I just installed a pull-pull system in a Four Star 120 and the unpulled line slackens during rudder deflection. Now I see that by placing the rudder control horns aligned with the hinge line was not the "better" idea. Had I read your link prior to installation I may have eliminated this problem. But since it is a huge trainer(4*120), it probably won't make any difference. Some night when I am sitting around bored, nothing to do, I will sit down and digest Alan's link and make a better install the next time. Thanks for the link. I now understand geometrically why the "unpulled" line slackens a bit. GEOMETRY!!!

Here's how I set it up in my Pup. Pic 1 shows the servos in the forward compartment to help with the cg. Second pic shows a standard crank for the rudder on the left and a home-made crank for the elevator on the right, I set in in some ball bearing blocks attached to the side of the fuse. Pic 3 shows how the wires exit. The rudder wires are crossed in the fuse, but I couldn't cross the elevator wires and try to keep it close to scale.

...and a pilot? What's he doing there?

LOL i was somewhat confused on the pilot myself, I had to look twice to make sure i saw it correctly

Anyone know what i can use for the exits of the wires out of the fuse what will not wear out the wire / or the wire will not chew into after awhile?

I saw the pull pull setup in the Alans hobby link, and he used teflon tubes, But will the wire eventually groove into those?

I use nylon tubing and it seems to wear forever, no problem on any of mine and some are several years old and well used. I use braided nylon coated fishing leader for the lines themselves and they also wear forever.