I am building a giant scale AT6. I need to install a pull-pull system for the streering. Does any body have any trick for drilling the hole for the cables to pass through. It is a fiberglass fus so ican't eye ball it with a long dowel or any thing. I am using a robart tail wheel so there is not a lot of room for error. Thanks for the help in advance- much appreciated[]

you could solder a drill bit onto a piece of music wire, using a piece of brass tubing to couple them together.

Take a look at this website. There are a lot of us that have been converted over the last couple of years. Brian D.Felice makes the proccess so simple you will have to wonder why we made it so complicated for so long.

http://members.cox.net/bdfelice/

Not that I've done millions of these, but once or twice I've had to measure and mark where the exit point should be. I install the servo and control horn (or in your case a tiller arm). Make a mark on the outside of the fuse indicating the height (vertical position) of the servo arm, then take a straight edge from that point to the control horn and draw a line along the path. Then look down on the servo and position one end of the ruler above the servo arm hole and the other against the control horn and make another mark on the fuse where the ruler crosses the wall of the fuse. then draw a line from that mark perpendicular to the first one and X marks the spot.

Peter

It is accepted pratice in pull-pull for the width of the servo arm and control horn to be equal. The exit point for the cables will be at the location where fuselage width equals that measurement.

The only other variable will the vertical placement for the exit. A little measuring and eyeballing should get you pretty close.

When I installed my latest pull-pull system, I decided to make use of a bit of modern technology... Lasers. In particular, I got one of those laser levels for Christmas this past year and found that they can be very beneficial when doing installations like the pull-pull. They shoot a perfectly straight line, which is also a perfectly flat plane. Most of the laser levels can be attached to a tripod. In this particular case the pull-pull servo is located in the cockpit area. I set the fuse upright on a flat table and placed the laser perpendicular to the fuse and shot a laser line along the side of the fuse... the line past from where the servo arm is to the control horn. While the laser line is illuminated on the fuse, I placed a small piece of low stick masking tape in the area where the cable will exit the fuse, with the laser line riding on the top edge of the tape. (tape was about 3 inches long). I did the same for the other side of the plane. Now for step 2, I placed the fuse on the floor and mounted the laser level to a tripod. I placed the tripod so that the laser is directly over the pull-pull servo and again shot a line from the servo arm to the control horn. Where that laser line crosses the top edge of the tape is exactly where the hole should be drilled.

I tried this out as kinda an experiment, but found it worked easier and better than I expected...after I had drilled the holes they were EXACTLY in line. My control wires touch NOTHING between the servo arm and control horn.

I have also discovered that the cheap key chain type laser pointers also come in handy for shooting down surfaces or through fuselages to find obstructions or nonconformities... it's like having a perfectly stiff wire that does not bend, but is much easier to use than a wire.

Happy pulling,
SkyBound

I had an interference problem with my SpaceWalker when it was fitted with pull/pull for the rudder. I changed over to push pull ( no wires ) and it was ok. Im thinking about using fishing line instead of wire and wonder if anyone has tried this? I dont see why it wont work and It should eliminate the potential interference from those 2 wire lines. Pull Pull is much better.

???

Bill

Bill:

Not sure which Spacewalker you have but I changed my GP Spacewalker to pull-pull on rudder and used 50# Spider Wire (fishing line). I have flown this configuration for 2 years with no problems.

Works for me.

Dan

GP SpaceWalker and thanks for the tip/ Im onzaway to Walmart for fishin line!

Thats the way I do it also Marty.... I use a slide micrometer to measure the width of the rudder horn at the connection point...then just slide the mic up the turtle deck to obtain the correct width/exit point....then place a long straightedge on the fuse side to align servo arm heigth to the rudder horn heigth...a 1/2" lot or pushrod exit gives a very nice fit/finish and no rubbing!!!

very interesting,
I always wonder how you guys get the slack out of the cable prior to crimping?
I glued in the vertical stab for my Ustick60 yesterday and it refused to stay straight, so
i sanded the base of the stab until fit, grabbed the cable of my dubro 4-40 pull system package and wrapped it
around t-pins to keep the fin at 90, wasn't easy (no, i didn't have tape on hand) the cable didn't like to get wrapped around
the pin, forcing it tighter caused it to bend (more kink). so do you bend (kink) the cable once the desired
tension is ok or keep a loose loop and crimp it and get the slack out later with the adjustment screw?
I'm loosing my hair on this (my first) arf at mostly every stage of building when mods expand the choices.
good thing there is this forum, where people don't mind answering tons of Qs. from new arfbuilders.
cheers

The slack was the problem of my one and only so far pull/pull system. I believe and hopefully someone will correct me if I'm wrong, you get it as close as possible and tighten it up with the adjustment screw.
Pat

actually it wasn't that hard now that i did it.
easier then the rod/clevis thing.
of course something was wrong, I was told to have at least a 60 oz/inch torque servo to pull my
springloaded tailgear with.
and mine was a fut S3001.
changed it to a hitec 635 HB, boy are these servos strong, great response taxiing.
they also come with a nice 2 inch double servo arm that fit nicely in the geometry of
my rudder horns.
pat

I use eyebolts and clevises for pull-pull. If I'm using Kevlar, I run the 'cable' through a sleeve, through the eyebolt twice, and back through the sleeve. In most cases there is enough slight resistance that I can pull out the slack and it will stay out while I crimp the sleeve. If not, I give the sleeve a little squeeze with ordinary pliers, pull the slack out, and then use the crimping tool. And yes, you get the final line tension with the threaded eyebolt. At least, that's the way I do it.