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pull-pull rudder set-up

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Old 07-13-2013, 11:27 AM
  #1
the gipper
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Default pull-pull rudder set-up

I an setting up a pull-pull rudder on a Phoenix Extra 330S, and have never done a pull-pull set-up before. The instructions say to use crimping pliers once you feed the cable through the crimp connector. I don't have crimping pliers, but should be able to make the connection with needle nose pliers. My question is whether or not I should solder the crimp connections? This would give me more confidence in the connection, but I wonder if the heat would weaken the cable near the connection. I really don't think it would, but I'd really appreciate some input from somebody with experience with this type of connection. Thank you in advance for your helpful response.
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Old 07-13-2013, 11:54 AM
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Default RE: pull-pull rudder set-up

Here is the technique I use: I crimp the end of the ferrule near the loop, then I put a drop or two of CA into the open end of ferrule and crimp the other end, then one more crimp in the middle for good measure.

Al
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Old 07-13-2013, 12:18 PM
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Default RE: pull-pull rudder set-up

+1
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Old 07-13-2013, 12:53 PM
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Default RE: pull-pull rudder set-up

Hi!
You never solder a crimp connectror!
Just use a cutting plier and carefully crimp two or three times on each connector tubing.
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Old 07-13-2013, 02:37 PM
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Default RE: pull-pull rudder set-up

I , as jaka, use wire cutters with the cut edge ground flat just enough not to cut.
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Old 07-13-2013, 03:13 PM
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Default RE: pull-pull rudder set-up

Thanks to all of you for your helpful responses!!!!!! I have spare cutting pliers that I can blunt the edges on to do the crimping. And now I know that soldering was a bad idea. Thanks again!!!
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Old 07-14-2013, 04:02 AM
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Default RE: pull-pull rudder set-up

Yes, a pair of Dykes (cutting pliers) work well. You do not even have to dull the edge, just go easy on the force you use. If this is your first pull-pull system here are two very important things to watch out for. First, make sure you do not have any negative Ackerman induced in the setup, positive is okay as long as it is not excessive. Second, do not have the lines to tight, just enough to have no slack at neutral position. If you do not know what Ackerman is, you can Google it or do a search for it here on the forums. It is the relative placement of the attach points on the servo arms/control horns relative to the pivot point of the servo and moveable surfaces and how it effects line tension as the surface is moved off center.
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Old 07-14-2013, 06:36 AM
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Default RE: pull-pull rudder set-up

Thanks for your input Rodney. I just spent the last hour or so reading about the "Ackerman" effect online. I was familiar with the principal, but was not aware that it was called the "Ackerman Effect". I used to use the same principal to get differential aileron travel in the old days, before we had "Computer" radios. The input from all of you has been very helpful, and much appreciated.
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Old 07-14-2013, 06:50 AM
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Default RE: pull-pull rudder set-up



I account for all of Rodney's points, which are good points, by way of adjustable clevises on the servo with a spring between the clevis and the wire. The clevis is, well, for adjusting and the springs maintain tension in the circuit while alleviating one side rotating farther than the other during operation.

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Old 07-14-2013, 10:01 AM
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Default RE: pull-pull rudder set-up

I don't have crimping pliers either. I used to use the side-cutters on pliers VERY carefully and it worked fine. Now I use round-jaw pliers and put in the three crimps that combatpigg mentioned. I also crimp slightly diagonally to make each crimp slightly longer. No failures or cables broken at crimps but I don't honestly know if the diagonal is a good idea or not. No problems though. I don't do anything additional - no glue or solder or anything else.
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Old 07-14-2013, 10:21 AM
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Default RE: pull-pull rudder set-up

Hi!
Yeah! I don't dull my cutter plier either, but you have to be carefull when you crimp the tubing.
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Old 07-14-2013, 04:51 PM
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Default RE: pull-pull rudder set-up

I like to put some shrink sleeve over the ends of the wire after crimping.

Terry
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Old 07-14-2013, 05:10 PM
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Default RE: pull-pull rudder set-up

Assuming the rudder horn connections to be on the hinge line, would the best set up be equi distance between cables at servo and rudder?

T-man49
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Old 07-15-2013, 07:34 AM
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Default RE: pull-pull rudder set-up


Quote:
ORIGINAL: triumphman49

Assuming the rudder horn connections to be on the hinge line, would the best set up be equi distance between cables at servo and rudder?

T-man49
I often see this as a requirement but; it is not. As long as, when the servo is at full throw, no binding occurs. The horns can be either longer or shorter than the servo arms if there is no negative Ackerman in the system. I always like a little positive Ackerman in mine (where the non pulled line gets a bit slack as the surface is moved away from neutral). This slack will not hurt a thing and; no, it does not contribute to flutter in way, shape or form nor detract from firmness of control. It is also the easiest on your servos as there is no current increase as happens if the line tightens under movement.
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Old 07-15-2013, 11:34 AM
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Default RE: pull-pull rudder set-up

Just to throw a curve at ya try servo wheels on servo and in the rudder they have 2 grooves been doing this for years no binding or over centering.try it you mite like it.just a thaught.
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Old 07-15-2013, 01:27 PM
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Default RE: pull-pull rudder set-up

Hey Rodney
Thanx for the response and explanation. Yours I could picturre and understand .

DaDragon, Yours, I couldn't get the picture. Do know how to use servo wheels to set up differential, as for ailerons. Mabey a diagram ? ? ? or another try at explanation ? ?

Many Thanx
T-man49 in Al
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