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slopeflyer

Z bend pliers

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slopeflyer

Guys, I need to do a z bend on the rudder linkage on my 4001 pro. The manual seems to imply using a z bend on the existing piano wire linkage. What are the best pliers given I need to buy a set. Was thinking of PMPs but they arent that cheap.

Is the connection decent and slop free if I go this route?

I could solder a connector and clevis or even try some other linkage.

What are the pros/cons of each method?Thanks.J.

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Fubar

These are the Z bend pliers I use Jimbo, Taiwan's finest. Cheap as chips from E Bay, but they work and keep on working fine.

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Bustergrunt

The alternative solution is to put a small 90 degree bend in the wire, then Bind with fuse wire and solder a small length of wire in parrallell to the "long side" which then goes slightly past the bend and therby prevents the wire from disengaging from the horn.

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isoaritfirst

bend 1st 90 degree then bend second at right angles to that. once you have it about right straighten it out. All very easy to do with standard pliers.

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slopeflyer

I did try that but once the wire hits a certain diameter/quality adding the 2nd is pretty impossible.

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Andy_B

slopeflyer said:

I did try that but once the wire hits a certain diameter/quality adding the 2nd is pretty impossible.
If youve got to that situation then Z bend pliers wont overcome it

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Spoons

Z-Bend for mouldies = mondo slop !Z-Bend for foamies, well its a piece of foam so who cares !

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slopeflyer
Z-Bend for mouldies = mondo slop !Z-Bend for foamies, well its a piece of foam so who cares !
That's what I thought. Was waiting for that post. I might try and solder a rod/clevis on.

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Spoons

I have used JB weld sucsessfully in the past to hold on clevi onto the end of push rods.Rough them up a wee bit with your dremmel disc to give a good key.

Jon

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f3fman

Andy_B said:

If youve got to that situation then Z bend pliers wont overcome it

I bend mine in a metal jawed vice, and use a perma grit sanding block to push the wire over, then twist it round by 90 degrees, with lots of leverage it seems to work ok for me. :D

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isoaritfirst

With a rudder just do a simple L bend.

Arrange it so that the push rod cannot come out without either a large amount of flexing or removing the rudder from its hinge. I use L bends for the elevator connection on my Pilatus. and use them regularly on rudders.

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Fubar

What material and diameter are you trying to bend also what is the application ?

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Yoyo

isoaritfirst said:

With a rudder just do a simple L bend.Arrange it so that the push rod cannot come out without either a large amount of flexing or removing the rudder from its hinge. I use L bends for the elevator connection on my Pilatus. and use them regularly on rudders.

I have been persuaded by Tony Fu that an L bend with a thread on the pushrod end and a tapped hole in the horn works well - yes you need to screw it on, but Z-bends aren't that easy to get off either.

Other than that, an L bend with a clip on keeper is a relatively low-slop alternative to a Z bend. Although I prefer these anyway, with no real slop at all: http://www.brchobbie.....8;item=644

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isoaritfirst

No need for any threads and often the line of the push rod works well enough as the keeper, especially on a rudder. You can of course leave the tang a little longer for extra security. But just make the exit from the fuselage tight and well located and rod will stay put without problems.

Even better if you have to install the rod in the eyelet before taping the hinge in place. The Pilatus elevator is a good example where the rod is passed through the eyelet before the tailplane is screwed in place, once fitted it cannot come out, and with good design the rod runs cleanly with no side slop because of its line through the fin.

I have used threaded L bends but unless you use a very good quality rod like a bike spoke then I have always been nervous of the rod breaking at the bend which by necessity is on the end of the threads.

I prefer just a smooth bend and an arrangement that keeps it in place. With an aileron you could simply use a rib between the top and bottom skin, use balsa and tack it in, break it out if you need to remove the rod.

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slopeflyer

That's an Interesting idea mike and would probably work in my case.. With caveats. However, there is no eye like on the B4 and the securing is just the pushrod tube epoxied to the fuse side. After time it may work loose.

There would also be some slop as the last fixing point Of fuse to the rudder linkage is about 2 inches from the horn.I'm still thinking soldered clevis might be the best slop free linkage over a longer period.

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slopeflyer

Andy_B said:

If youve got to that situation then Z bend pliers wont overcome it

I bend mine in a metal jawed vice, and use a perma grit sanding block to push the wire over, then twist it round by 90 degrees, with lots of leverage it seems to work ok for me. :D

I will give this a test on a old bike spoke tomorrow.. If it works on that it will work on the piano wire :) Thx.

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f3fman

I will give this a test on a old bike spoke tommorrow.. If it works on that it will work on the piano wire :)

Thx.

I do this on bike spokes and piano wire, if you want nice square corners then as soon as the bend is made around the edge of the jaws you can then "whack the wire at the bend with a hammer" (technical term) as it can be a little curved on the tougher wire.

Good luck with your experiments tomorrow. :D Oops, something wrong with my use of the quotes system! :confused:

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slopeflyer

Well I actually have 2 airbrakes to do as well. So I'll be investing in a pair of pliers anyway I think. Thanks for the info anyways.

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Tony Fu

Hmm, not on here often enough it seems but for what its worth I never user z bends for any linkages. They just have too much side play and slop, besides it only really works with bendy wire or bike spokes and no good with nice 303 grade stainless steel stuff I tend to use. Then I'm very anal about linkages.

L bends, especially threaded are a bit of work and can be awkward as needs to be screwed on. I now have a simpler solution and its these adaptors threaded for 2mm pushrods. They run on a M2 short bolt (hole sized 2mm) either threaded or bolted on with small nut. It's for use when a clevis is impractical usually because too big and you can't be bothered to grind loads away. It's brass flats are 2.4mm thick and strong!

The benefit is that they run tight to the arm or surface that you are driving and so introduce less side load than an L bend. Even if you bash an L bend with a hammer its very unlikely you will have a bend that is not raised. Anyway, it use to take me well over an hour to tap and cut 2mm threads and make 4 perfect 90 degree L bends for a wing install. (That's a knack in itself as bending stainless steel with 2mm threads is not straight forward and I used to get a lot of failures until I discovered a way of doing reliably). Now I just take these adaptors out of a packet, job done! They are especially machined for me to my specs.

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Andy_B

20 to 3 in the morning .......I was going to say you need to get out more Tony..but maybe you had .... :)

Thats the way VV had been doing there servos for years ...but does seem more elegant .....BUT ...custom made for you ...comon get some in stock for us plebs .............

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