Attaching pushrods to servo
 

Whats the best way to attach pushrods to servo arms? I am finishing up an Avistar ARF it uses E/Z-connectors but I am worried about them slipping. I was thinking about just using Z-bends. Thanks.

RE: Attaching pushrods to servo
 

Zee bends have too much slop in them. I've used EZ connectors and have never had one fail yet. However, the best is the clevis that screws in to the push rod and the snap is held in place on the servo arm with a piece of silicon tubing. Generally, most of the ARF planes have this stuff included in the box.

Dave...

RE: Attaching pushrods to servo
 

I tend to disagree somewhat (except that I have never had any problems with EZ connectors coming loose either) about the Z-bend comments above. :)

If done properly and precisely, z-bends have very little, if any, "slop" in them. The great thing about them is that they are 100% reliable. they certainly have their proper place in our hobby. I use both methods about equally and try to weigh in what's appropriate for "this" particular application.

Good luck.

RE: Attaching pushrods to servo
 

If you use the right kind of servo arm and right size push rod you should have no slop at all when using Z bends. I usually have to drill out the servo arm hole to accept the Z bend and I make sure its a snug fit. I fly a profile morris Knife and a Giles 300 60 size with duel elevator servos and I have no slop in their movements at all. Just an opinion.

RE: Attaching pushrods to servo
 

I use both z bends and E/Z connectors. I have never had an E/Z connector come loose, however, once I have made my final adjustments on the E/Z connector, I put a drop of locktite on the screw.

RE: Attaching pushrods to servo
 

I've ran about 16+ ga. through my Avistar ARF-LA46 with all the
supplied parts.. And never had a single problem even with the CG
moved way back and throws maxed out... But as they say..
You never can be too safe.. Have fun!!

I take that back, I did change the throttle linkage for some give
just in case I nosed in.. Luckily I never put it to that test...

RE: Attaching pushrods to servo
 

I just use clevises. When you install them properly they are excellent. No slop at all.
I don't like Z-bends anyway, you have to drill a whole in the servo arm that's too big just to get the pushrod through it.

But anyway, that's just what I think about it.

Bart

RE: Attaching pushrods to servo
 

I have had one EZ conector come loose, but it was probably because I didn't use locktite (it was the elevator, no harm done, thank God, interesting landing though) Z-bends work fine, but I prefer cleveses, because they are easier to move if you want to adjust the throws

RE: Attaching pushrods to servo
 

I definatly agree on that one.


Bart

RE: Attaching pushrods to servo
 

Thanks for the responses. So if I decide to use clevises to connect the pushrods to the servo arms how would I attach the clevises if the pushrod is not threaded? Would I need to get new pushrods? Thanks.

RE: Attaching pushrods to servo
 

Hey Nas,

A Z bend at the servo is a good idea but I would go with the retainers for starters. I never had a failure with any of the hardware Hobbico supplied. They make pretty good stuff. Mostly a 90 is easier to get right than a Z if you are new to building.

You indeed must have threads for any clevis. That is how they attach and it is your adjustment point, Bend the 90 or Z as close as you can to suggested then screw the clevis in or out to get the trailing edge (control) surface perfect. Leave enough length at the threads for this without interfereing with a control horn.
You will need to do this again; at least I do; to get it flying perfect with no transmitter trim. Straight and level with no stick or trim input.
Let go off the sticks and the Avistar will return to normal flight if set up this way.
It is a great trainer plane and the manual is very helpful for new ARF builders.
Enjoy yourself with it. It will perform for you.

M

RE: Attaching pushrods to servo
 

Solder. There are both threaded and solder type metal clevises easily available.

RE: Attaching pushrods to servo
 

Using a short piece of fuel hose over a nylon clevis gives you false security. Yes, false security. Ever see a fuel hose, when used in normal fuel service, split at the end? If you have not you have not been flying much. When the short piece of hose is slipped over the clevis it is stretched 300% or 400% more than when the fuel hose is used on a fuel tank. The hose eventually splits on a fuel tank. When overstretched on a clevis it will not split?????? I lost two planes because I used nylon clevisis on the elevator, as the kit instructions directed. Now I put a Z bend on one end of the control rod, and a threaded Sullivan metal clevis, with locking clip, on the other end of the rod. This clevis cost a lot, close to $1.00 each. In the end it may be the lowest cost clevis there is since you can transfer it from plane to plane. You can purchase extral locking clips if you need them. At the throttle I still use a nylon clevis to prevent metal-to-metal contact. I change out this clevis occasionally. I try to eliminate problems. As a result all my crashes seem to be pilot error.

RE: Attaching pushrods to servo
 

Sure the fuel hose will split eventually, especially on the metal clevises. But that's why you do a pre-flight!


BTW, I like using 90's and the retainer clips myself, with an adjustable clevis on the flight control end. Exactally like the Avistar comes with, except I prefer the metal clevises. Them EZ connectors just make me nervous, but that's just me.


Andy

RE: Attaching pushrods to servo
 

IMHO, for .60 sized aircraft and below, making a 90 degree bend in the pushrod and attaching it two the servo arm using a snap keeper (e.g. E/Z Link [link=http://www.dubro.com/DU-BRO/DUB_CAT/DUB14.html]Dubro E/Z Link[/link]) is the easiest and least problematic way to hook up the servo. I have never had a failure with snap keepers. At the other end of the pushrod I have been using threaded clevises quite a lot, but lately I am using ball links more and more.

IMHO, Z-bends are a pain in the ...


/Red B.

RE: Attaching pushrods to servo
 

FWIW, After trying ball links, clevises and Z bends, I settled on using a 90 degree bend with the end going down thru the servo arm, secured with a "half clevis" type of retainer... simple, few parts to fail, reasonably cheap and nearly bulletproof.... Usually need to drill out the servo arm holes, so can pick the right size drill to ensure no slop... ;) If a lot of adjustment is required, will use a screw type clevis....

Cheers!

Jim

RE: Attaching pushrods to servo
 

I'll stick with Z-bends at the servo arms and clevises at the control horns. If you measure right, you have plenty of adjustment with only one clevis and Z-bends are bullet-proof. I prefer the clevises outside, where I can adjust them easier and ALWAYS use the little retaining clip, not fuel tubing.

RE: Attaching pushrods to servo
 

Stick with the EZ links. They're great -- I've never had one fail in many years of flying.

RE: Attaching pushrods to servo
 

It is quite easy to put threads on a metal rod you just need to use a die, if you don't have one i'm sure you know someone who does :)
I have had to change the threads on the rod or the clevis quite a few times in the past when i have purchased better quality fittings because i didn't trust the hardware in the kit.

RE: Attaching pushrods to servo
 

Some of the new Z-benders will allow you to position the bender right on the hole in the servo you want to use, and you just lay the wire in the bender. A good squeeze, and you have a Z-bend exactly where you want it.

bax