Need pushrod ideas - RC Groups
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Oct 27, 2017, 04:55 PM
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Need pushrod ideas


Most of my 3'+ ws models use ez connectors on one end of the pushrod allowing them to be adjusted or disassembled.

But many of my small planes have short Z-bends glued & heat-shrunk to a carbon rod at each end. Very difficult to adjust or disassemble. And I think the .025" Z-bend end wire is too small and the horns are too small to fit a typical ez connector. Any thoughts as to how to build adjustability into these small parts? I need to replace some servos and the first step needs to be taking a razor to the pushrods to get them apart.

Since the wire is .025", I assume the holes in the small horns and arms are only a few thou larger than that.
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Oct 27, 2017, 06:08 PM
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Yeah, maybe. The sockets are too big to fit the Z wire but too small to fit the carbon rods. Still, some sort of adaption could be made. DuBro has another style micro clevis, but it offers the same selection of sockets. I think I'll order up both and see what I have to work with. Thanks.
Oct 28, 2017, 09:59 AM
Registered User
See if something like this may work. I found it on the SPAD forum. Adjustable pushrod. Don't limit yourself to RC products. Look in the hardware store for suitable products that may be used.
Oct 28, 2017, 10:06 AM
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I'm also ordering some micro ez connectors that I know are still too big. But perhaps I can modify them into a clamp like above. Advantage is they're aluminum -- I think a minimum weight solution is going to be important.

I wonder if I could drill a through-hole under the head of a nylon screw and clamp with just a short nylon screw & nut?
Oct 28, 2017, 12:29 PM
Registered User
If you can't find small enough commercially available adjustable links at the flying surface end, why not build adjustability of the length of the rod at the servo end, where a bit of extra weight is typically less of an issue.

On some very small planes.... such as a UMX Carbon Cub that I have - the music wire at the flying surface end is .020" (I measured with a micrometer), which use a Z-bend connection to the horn and, for adjustability, there is a U-shaped dip in this music wire; the bend is opened wider to make the linkage longer; made narrower to make the linkage shorter. This is done with some needle nose pliers. The bend is not a V shape but a U shape with the bottom two corners being rounds.
Check the available online manual on the UMX Carbon Cub, etc.

Michael in Ontario, Canada
Oct 30, 2017, 01:55 PM
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DGrant's Avatar
Since these are small/micro, and very light obviously, is there any way to put what we call an "adjustment kink" into the pushrod itself?

You will need to lengthen the pushrod when you replace it... but an 1/8" or less "kink" bent into the rod can allow adjustments by a simple bend/tweak right on that "kink". I say kink, but its not any sort of tight bend... just loose enough to allow for small tweaks.

This technique was/is used quite a bit in profile U-control planes, where there's much less adjustment once the bell-crank is sealed/built into the plane.... so an adjustment kink is put into the pushrod... and adjustment is made using that bend/kink... in this case usually right about midway down the fuselage side.. and starts with about a 45degree bend... which seems to be a good ballpark.. as you can straighten it out a bit if the rod is too short, or you can bend it a bit more if your rod is too long. I hope this makes sense.

With the lightness, and less stressed pushrods on a small electric, if there's enough room somewhere to put such a bend in that rod. It can be located anywhere along the routed where's there's the most access... all depending on the model of course..

Pushrods and linkages can be challenging, but with patience and planning, most anything can be adjusted perfectly...

So here's at least an idea or two for you. Good luck.
Last edited by DGrant; Oct 30, 2017 at 02:06 PM.
Oct 30, 2017, 02:01 PM
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DGrant's Avatar
There's also a few different ways to bend pushrod ends that can be very effective... not all pushrod ends have to be "Z'd".... as someone pictured above... but there's several more creative ways to bend wire to be able to connect/disconnect and possibly adjust from different points.

I find smaller/micro wire very easy to work with, as it doesn't take as much effort.. haha.... as long as I don't get carried away, as it's not as strong as larger wire... but alot can be done with a gentle touch...and remembering it's not a giant scale plane.
Last edited by DGrant; Oct 30, 2017 at 02:17 PM.
Oct 30, 2017, 02:35 PM
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I understand what you're saying, but my pushrods are 95% carbon rods. Only 1/4" at each end is steel wire. Hence the interest in a releasable/adjustable ez connector, but smaller than what I've found on the market. My primary hope for this thread was that someone would know of a source for similar but smaller than DuBro hardware.

There are a lot of plastic clevises that thread onto wire pushrods. They seem to start at a bigger wire than I use, but perhaps just a couple inches of that wire wouldn't be a big weight hit.
I think I'd have to buy the threaded pushrods and cut off an inch or so of the threaded end to attach to my carbon rod. I don't see myself trying to cut threads on a tiny wire.

I also recently built a small TechOne plane with unusual plastic clevises that slide onto wire and are retained by a grub (set) screw. I've never seen them for sale separately, but that doesn't mean they aren't.
Oct 30, 2017, 07:57 PM
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DGrant's Avatar
There's still many creative ways to run linkages and have adjustment. I'm sure you'll do fine, as you seem to know exactly what you're dealing with. I've been challenged many times over many years myself... with micro's and giants alike.

Have you thought of putting a micro EZ connector right on the control-horn itself(yes.. the one mounted on the control surface ) ? I've done that myself actually on a micro, and that makes easy work.... matter of fact, on a micro, you can have an EZ connector on each end of the pushrod... and not worry about Z-bending... but again, there's other bends that can be used... It's a matter of knowing, and having the experience is all.... but an EZ on both ends would work fine. Then all you have to do is make sure you get that c/f pushrod the right length... but hey.... that's a cake walk right.

ET's pic #4 is one example of course... but what if that EZ connector were mounted on that control horn?... hmmm.... yes... I know exactly what... It would alleviate any bending of the wire)as in Z-bend, or hook-bend), and it would be fully adjustable with total access to the adjustment screw. Those are the kind of outside the box ideas that can be had... as I have a few micros that have some very decent adjustable linkages... and yes... very small.... there's alot of experience on these forums... many of us have overcome pretty much exactly issues that you're dealing with... but maybe not... I'm willing to learn myself here.....

Here's an idea... check these out... They're micro EZ type connectors....

Install one of these into the control horn itself:

https://www.towerhobbies.com/cgi-bin...?&I=LXNZX9&P=7

...instead of trying to get the adjustment at the servo or along the pushrod route.. get your adjustment right where the pushrod meets the control horn. Other then that.... maybe a pic would tell more of what you're dealing with... don't know though.... I've seen many configurations... as I said though, I wouldn't mind seeing a new one if yours is that unique. As you're saying you have 1/4" of steel wire at each end of the pushrod... That's quite a bit of area for a micro.... I hope you don't need that much adjustment on a micro.... LOL
Good luck with it.
Oct 30, 2017, 08:06 PM
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DGrant's Avatar
Matter of fact, the idea just hit me... can you go direct into the EZ connector with the c/f?... and get rid of the steel all together. I was just looking at one of my older mini planes that I did just that with.... see.. there's many ways you could go.

Without pics or more info, its tough to know what to say to help... so.. anyway... the above Towerhobbies link is to the micro EZ connectors that you eluded too.... and yes.. they're very small.... micro to be exact.
Oct 30, 2017, 08:27 PM
Registered User
Here is a picture that show a pushrod bend for length adjustment. Just one way. I use a modified bend that lets me rotate a pushrod for easy removal from the control horn. As pointed out there are a few ways to do the linkage.
Oct 30, 2017, 09:02 PM
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Got in my first parts today. Was thinking DuBro 973 was the answer. With a little work I could insert a .050" carbon rod directly into a .047" socket. And the socket/clevis pair was only .04g according to the website. But like most things too good to be true, that hardware does not weigh .04g...it weighs .4g. Someone can't read a scale. Or a typo, but it applied to all three sizes. Weight aside, it's a very straight forward and clean approach and meets all my needs.

In case anyone cares, the three sizes are all identical clevises and identical adapters except that the rod end ID changes from part to part. The two parts weigh approximately .2g each and you can probably trim half the brass away to save some weight.

So I know what I need to know about this part. I have a couple others coming.

https://www.dubro.com/products/long-arm-micro-clevis
Oct 30, 2017, 09:03 PM
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DGrant's Avatar
I was looking at StevensAero.com, at their small/micro hardware, had an idea about using a wheel-collar, that's just large enough to insert 2 peices of the carbon-fiber pushrod material... and capture those, if you could do that, you'd have an adjustment section right there where there at the wheel collar(which would essentially be called a "pushrod collar" at that point... so there's another idea. Similar to ET's idea, only using a wheel collar(which I've done in the past as well)... and there's many many sizes of wheel collars out there no doubt.
Oct 31, 2017, 03:08 PM
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slopemeno's Avatar
A friend of mine had a nice idea when dealing with issues like this.

Cut the Z-bend off of the pushrod with about 1" to spare, and cut an additional 1/8" off of the wire pushrod. Slip a piece of brass tuning over the wire, and insert the straight part of the z-bend. Heat it up with a soldering iron and zero your radio and the control surface. Solder the z-bend, brass tubing, and pushrod together. Now if you need to adjust it, go to sub trims. if you need more, hit it with he soldering iron.

I've also used the Sullivan connectors that are 2-56 threaded and have a .032 hole through them- just solder in place and add a clevis.


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