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-   -   Carbon Fiber Push Rods ?? (https://www.rcuniverse.com/forum/composites-fabrication-repair-97/10760393-carbon-fiber-push-rods.html)

Cougar-RCU 10-11-2011 02:53 PM

Carbon Fiber Push Rods ??
 
Hi gang, not sure if this is the right place to ask this question or not.
I am wanting to make up some carbon fiber push rods with metal
threaded rod on each end. what is the best way to do this procedure?
Or direct me to a link that shows how to do it?
Thanks for your time!
Jeff

k12rc 10-11-2011 04:23 PM

RE: Carbon Fiber Push Rods ??
 
rc foam has square carbon rod you can tap for 4/40 go to hobby shop and get the [email protected] square tubing to go over the end for about a inch so it will not split on you if you need size I will take pic and measure tomorrow the square is really strong

Scorpion Racing 10-12-2011 06:09 AM

RE: Carbon Fiber Push Rods ??
 
We do it all the time for pylon airplanes. Here is a site that both sells the parts and explains how to do it: [link=http://www.darrolcady.com/Carbon_Fiber/carbon_fiber.htm]Darrol Cady[/link]

Scott Hartman does a good job showing it in a couple of his build threads:
[link=http://www.nmpra.org/phpBB3/viewtopic.php?f=12&t=2710&start=10]Radio Installation[/link]
[link=http://www.rcuniverse.com/forum/m_10603350/mpage_4/tm.htm]post #78[/link]

I do mine the same basic way with a 1/8" OD (.093" ID) carbon rod, 2-56 (.093" Dia.) control rods, 1/8" ID aluminum tubing & JB weld. If you need a larger rod size, just take the control rod diameter, match it to the ID of the carbon rod, cap the ends with a matching piece of aluminum tubing and assemble it as shown in these examples.

Hope that helps some! ;)

Cougar-RCU 10-12-2011 06:19 AM

RE: Carbon Fiber Push Rods ??
 
Thank you very much Scott !!

Scorpion Racing 10-12-2011 06:50 AM

RE: Carbon Fiber Push Rods ??
 
Your very welcome! :D

Cougar-RCU 10-12-2011 07:28 AM

RE: Carbon Fiber Push Rods ??
 
k12rc

I would like to see a picture of that as well, thanks

k12rc 10-12-2011 04:58 PM

RE: Carbon Fiber Push Rods ??
 
1 Attachment(s)
hope this helps not to clear but I hope you can see what i'am talking about

Cougar-RCU 10-13-2011 01:13 AM

RE: Carbon Fiber Push Rods ??
 
Thanks very much k12rc !

k12rc 10-13-2011 03:30 PM

RE: Carbon Fiber Push Rods ??
 
anytime

jetfixr 10-13-2011 07:04 PM

RE: Carbon Fiber Push Rods ??
 
I use 4-40 rod that slides into a piece of carbon fiber tube without twisting it in. Then I get some fine sewing thread and wrap the threaded rod for about 1/2 inch until it barely slides into the tube. Then I soak it in medium CA and shove it in. Works great, has never failed, is very simple, and done in less than 5 minutes. I have physically tried to pull it out and cannot. I have used this method on every pushrod on 2 different 50cc 3D planes without a problem. However, I have had some split when trying to thread rod into CF tube. Good luck!

Jeff

Cougar-RCU 10-14-2011 11:26 AM

RE: Carbon Fiber Push Rods ??
 
Do you guys thinks these arrow shafts cut to size would do the trick?
http://www.goodwinds.com/?gclid=CJ-o...FQsBQAod5nezXw
They even have solid as well. I was thinking the hollow ones and
JB weld the ends into them. The reason I want to do this is my GeeBee
60 comes with the wooden dowels and the flex to much.
Thanks for your opinion
Jeff

jetfixr , do you also have a picture of that type set-up?

k12rc 10-14-2011 01:36 PM

RE: Carbon Fiber Push Rods ??
 

ORIGINAL: jetfixr

I use 4-40 rod that slides into a piece of carbon fiber tube without twisting it in. Then I get some fine sewing thread and wrap the threaded rod for about 1/2 inch until it barely slides into the tube. Then I soak it in medium CA and shove it in. Works great, has never failed, is very simple, and done in less than 5 minutes. I have physically tried to pull it out and cannot. I have used this method on every pushrod on 2 different 50cc 3D planes without a problem. However, I have had some split when trying to thread rod into CF tube. Good luck!

Jeff
they won't split if you wrap carbon shaft first and soak in ca I use allinium tubing to cover end carbon

jetfixr 10-14-2011 02:36 PM

RE: Carbon Fiber Push Rods ??
 
That is true. They won't split if you put aluminum tube over the ends. I just like the setup I used for simplicity reasons. I don't know if I have a picture or not. I will look, and if not I will make one to show you. It sounds complicated, but it is really easy.

Jeff

k12rc 10-14-2011 04:08 PM

RE: Carbon Fiber Push Rods ??
 
thanks would like to see them

jetfixr 10-14-2011 08:19 PM

RE: Carbon Fiber Push Rods ??
 
1 Attachment(s)
The pictures are a little out of focus, but I think you can get the idea. First find all thread rod that fits the clevis you want to use. Then find a piece of CF tube that slides over the all thread pretty easily. Next wrap about 1/2 inch of the all thread with sewing thread. Do this until you have a good snug fit in the CF tube. When you have all of the thread on, soak it in medium CA and quickly slide it into the CF tube. I usually hold the all thread with needle nose pliers at the point that I want the CF tube to stop. This way I can slide it on quickly and not have to worry about going to far. This is a one shot deal though. The all thread is completely locked in place now. The CA makes a very good bond with the inside of the CF tube. Hopefully the pictures illustrate this well.

Jeff

Cougar-RCU 10-15-2011 03:03 AM

RE: Carbon Fiber Push Rods ??
 
Jeff, now that's is a great idea!! So are you just using CF arrow shafts
and If so what size are they? thanks so much for the pictures, worth
a thousand words. So from what I am seeing , wrap threaded wire to the
point that the threaded rod just slips in CA it and your done. how far into
the CB shaft are you setting the threaded rod?
Again THANKS!
I was thinking after the CA is done why not add just a dab of JB weld on the end for
extra safety? :-)
Jeff

Scorpion Racing 10-15-2011 05:36 AM

RE: Carbon Fiber Push Rods ??
 
Jeff,
I think the arrow shafts are overkill for a 60 sized plane. We use 4-40 rods on a Q40 which is going around 200 mph and pulling 15 G's in a turn! ;)

I would buy some 4-40 pushrods, 3/16" aluminum tubing, JB Weld and use a 3/16" carbon tubing for the shaft. This works for Q40 racing and is more than you will need. This is how I do my rods:

1.) Cut the 4-40 pushrods 1 1/2"-2" past the last thread.
2.) Put a z-bend in the left over piece of pushrod, and cut it off about the same total length as the threaded side.
3.) Cut a 1" long piece of the 3/16" aluminum tubing for each end of the rods.
4.) Cut the carbon rods to size and use thin CA to glue the aluminum tubing to the end of each one.
5.) Rough up the ends of the pushrod to be inserted (1 1/2"-2") with sandpaper, and clean the inside of the carbon rod and the pushrod with solvent.
6.) Mix your JB weld, put a dab on the end of the hole in the carbon rod and coat the pushrod end to be inserted.
7.) Gently work the pushrod into the carbon tubing. Clean up the excess JB weld with solvent and tape it in place until dry.
8.) After dry, you can add your clevises and attach to the servos and control surfaces and go fly.

Alternatively to taping the rods and waiting for them to dry, you can add the clevises before inserting the pushrods into the carbon tubes and simply assemble the rods inside the aircraft using the servo and the clevis attached to the centered control surface. This is what I do most of the time, but it assumes the radio gear is in, all servos are centered and geometrically correct, control surfaces are attached and can be secured centered (tape or clamps) and you have everything ready to go. You have to secure the rods while drying due to slight pressure in the tub from inserting the pushrods and the air being trapped. It isn't much, but it may push one rod out slightly longer than you wanted.

It really is easy to do, and will only take you a few minutes to complete. Much quicker than the wooden dowels, a fraction of the weight and no flex or trim fluctuations due to temperature expansion of the wood.

Best wishes

jetfixr 10-15-2011 06:20 AM

RE: Carbon Fiber Push Rods ??
 
No, they are not arrow shafts, but just some CF tube that my local hobby shop had in stock. I believe they are quite a bit smaller than arrow shafts. I usually wrap about 1/2 inch of the all thread with sewing thread, and then insert the rod 1/2 inch into the CF tube where the sewing thread ends. You could also use some JB weld after, but I never have. Like I said, I have tried to pull one out by hand and could not. I have had this system on 2 50CC 3D planes, and I am also using it on a 10ft wingspan scale twin. I will probably use it on anything I build from now on. Like I said, it is extremely easy and fast!

Jeff

Cougar-RCU 10-15-2011 06:38 AM

RE: Carbon Fiber Push Rods ??
 
Now to just find that tube someplace ! haha :D

js3 10-15-2011 08:12 AM

RE: Carbon Fiber Push Rods ??
 


ORIGINAL: Cougar-RCU

Now to just find that tube someplace ! haha :D
[link=http://www.darrolcady.com/index.htm]Darrol Cady dot com[/link] is where to get them.

Cougar-RCU 10-15-2011 08:17 AM

RE: Carbon Fiber Push Rods ??
 
Now to get the right Die,. what did you use Jeff ? 4-40 / 2/56 ? I am thinking it's the 4/40?
Is the threaded rod the same for the tube size as well when I order? Thank for putting up with me guys , it will end soon *LOL*
Thanks
Thanks js3

k12rc 10-15-2011 04:34 PM

RE: Carbon Fiber Push Rods ??
 
thanks jeff good idea

jetfixr 10-15-2011 07:10 PM

RE: Carbon Fiber Push Rods ??
 
Yes, I used 4-40 all thread, but the CF tube is measured differently. Like I said, I just tested them at my LHS to get the fit I wanted. A lot of hobby shops do have CF tube stock that you can test.

Jeff

Cougar-RCU 10-24-2011 02:14 PM

RE: Carbon Fiber Push Rods ??
 
THANKS JEFF !!! Your method works like a charm, wow I really do not think that threaded rod is
going any place soon, it is REALLY locked in place !!

I ended up finding one hobby shop about 45 miles a way and that kinda gave me the idea on
what sizes to get. they only had a couple size's to look at, so I went on-line to Tower and
got my digital calipers out and ordered away!!

Again thanks for the great tip !!

Jeff

jetfixr 10-24-2011 05:57 PM

RE: Carbon Fiber Push Rods ??
 
Great! I am glad it worked well for you. They are definitely one of the easiest and strongest pushrods I have built, and they are easy to make to any length. I also like how quick they build.

MTK 10-24-2011 07:36 PM

RE: Carbon Fiber Push Rods ??
 


ORIGINAL: Cougar-RCU

Now to just find that tube someplace ! haha :D
Aerospace Composite Products is one good source. The .156" x .118" size fits the 4-40 nicely. They also have the .120" x .078" which fits the 2-56. Jeff's method is my method too...I've done that for many years on Pattern planes. I also use the tail of the thread to wrap the carbon tubing end and ca the thread in place. That's to keep any potential split from happening. I have also used aluminum tube over the end of the carbon and that work well too

kenh3497 10-26-2011 04:43 PM

RE: Carbon Fiber Push Rods ??
 
Is there a "formula" to use to determine how large a diameter CF rod you will need for a given plane? I know length would be a determining factor as well as load which may be harder to determine unless you use the MFG's recommendations for servo size/oz. of torque.

Ken

Avaiojet 11-01-2011 02:47 PM

RE: Carbon Fiber Push Rods ??
 
I still have and use the Dave Brown pushrods.

Probably not liked as much because of the thickness.

Anyone using the Dave Brown pushrods?

Charles

kenh3497 11-04-2011 05:56 PM

RE: Carbon Fiber Push Rods ??
 
I bought a BUNCH of balsa from a guy and there was a set of DB push rods in with the balsa. I plan on using them in a future project.

wahoo 11-25-2011 01:00 AM

RE: Carbon Fiber Push Rods ??
 
1 Attachment(s)
<span style="font-size: medium; "><span style="font-family: 'Comic Sans MS'; ">Try this.....

http://www.rcuniverse.com/forum/js/f...wink_smile.gif<br type="_moz" /></span></span>

pkoury 11-25-2011 09:14 PM

RE: Carbon Fiber Push Rods ??
 


ORIGINAL: Scorpion Racing

We do it all the time for pylon airplanes. Here is a site that both sells the parts and explains how to do it: [link=http://www.darrolcady.com/Carbon_Fiber/carbon_fiber.htm]Darrol Cady[/link]

Scott Hartman does a good job showing it in a couple of his build threads:
[link=http://www.nmpra.org/phpBB3/viewtopic.php?f=12&t=2710&start=10]Radio Installation[/link]
[link=http://www.rcuniverse.com/forum/m_10603350/mpage_4/tm.htm]post #78[/link]

I do mine the same basic way with a 1/8'' OD (.093'' ID) carbon rod, 2-56 (.093'' Dia.) control rods, 1/8'' ID aluminum tubing & JB weld. If you need a larger rod size, just take the control rod diameter, match it to the ID of the carbon rod, cap the ends with a matching piece of aluminum tubing and assemble it as shown in these examples.

Hope that helps some! ;)
If you are using carbon rod how do you drill the rod to accept the fitting? I have used carbon tubes but never tried the solid rod, are the rods that much strounger than the tubes to make it worth the effort to drill out the ends of the rods?

Scorpion Racing 11-25-2011 09:30 PM

RE: Carbon Fiber Push Rods ??
 
Sorry PK, I should have said carbon tube (Hence the inner diameter & the outer diameter dimensions). The tubes seem stiffer than the solid rods to me, as I have both. The solid rods only really work in you use the solder link threaded couplers and attach them to the outside of the rods. (the couplers come in brass, steel & titanium). I feel that the solid rods flex more, and I don't trust the glue joint or the solder link enough. I have had the brass & steel ones both fail, and prefer the metal rods inserted in to the carbon rads with the brass or aluminum tubes over the ends.

sorry for any confusion!


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