Carbon Fiber Pushrods for Split Elevator
 

I have searched the Universe and cannot seem to find a thread on how to create a carbon fiber pushrod setup for dual elevators.

I'd rather not have to use one of those elevator bell cranks.

Here are the two scenarios I am picturing.

1) On the servo end I would have a 2-56 or 4-40 metal rod inserted and fastened to the CF pushrod (I know how to do this step). On the other end of CF pushrod, I must somehow get two metal rods fastened to the pushrod for splitting to the elevator. It's this end that I start to get a little fuzzy. Please help.

2) Some how bind two CF rods together. Use the same setup above into one of the rods for the servo end. On the other end I can just insert a metal rod into each of the CF pushrods for the split elevator.

Is one of my scenarios above better than the other or should I look behind door number three?

If going with scenario number two above, what would be the best way to tie two CF pushrods together?

Please help or point me to a thread that may reveal the answer to my questions.

Thanks for your time and consideration,

Jeff

Split elevator pushrod
 

You may want to reconsider how to create the split elevator pushrod because of a problem that may not be apparent at first. If you have a single connection at the servo with a single carbon fiber rod going back to a 'Y' connection, you'll have to supply lateral support for the pushrod back at where the 'Y' is. That is, you must prevent it from moving side-to-side. If you don't, what will happen is that when you push down one elevator, the other one will go up, cause by the side force on the pushrod. This leads to some rather severe problems in flight (like major flutter!).

If possible, consider having TWO pushrods, one from each elevator half going all the way to the servo and only connecting together with the other pushrod as close as possible to the servo arm. There are several ways to accomplish this but the simplest is the wire-wrap and solder method.

If you're interested in this method and it's not clear how to make it, let me know and I'll e-mail you a simple drawing that should clarify.

HTH

Carbon Fiber Pushrods for Split Elevator
 

If possible, consider having TWO pushrods, one from each elevator half going all the way to the servo and only connecting together with the other pushrod as close as possible to the servo arm. There are several ways to accomplish this but the simplest is the wire-wrap and solder method.

CurtD, this looks like what I was talking about in my "scenario 2". I understand the theory but not quite the execution. Are you wire-wrap and soldering the CF pushrod at the servo end or do you have a section of metal wire protruding from each CF that you wrap and solder.

Your offer of a sketch would be much appreciated.

Thanks,
Jeff

[email protected]

Carbon Fiber Pushrods for Split Elevator
 

Dubro makes a "splitter" that is basically a Y-adapter. It has one threaded end at the servo side and two threaded ends at the pushrod side. This way you can run your pushrods full length all the way to the servo. Once you get to the servo, you connect both pushrods to the splitter and then the splitter to the servo arm. Hope this helps.
D

Carbon Fiber Pushrods for Split Elevator
 

Jeff,

I have been where you are and have tried the single pushrod with the "Y" and then tried tying 2 long pushrods back two a picece of square brass tubing. (Basically drill 3 equally spaced holes in the brass, attached the threaded rods from the pushrods using nuts. In the center hole use a piece of threaded pushrod with a clevis to attach the servo. Remember to cross the rods going back to the elevator halves. Rods have to be exactly the same lenght and the servo has to be in the middle for it to work right.) I don't like any of them. There is way to much slop with the "y" method and it takes a lot of fiddling to get the two pushrod set up to work properly.

I have switched to using two elevator servos. It just works better. If you don't have a 10X you can get an adjustable "Y" so that you can trim the one servo.

Just my 2 cents.

Andy

Carbon Fiber Pushrods for Split Elevator
 

Andy,

Obviously the dual servo for split elevators is the way to go.

I abandoned the idea becase I didn't think my Hitec Eclipse could mix two channels for elevators.

Didn't like the idea of a "Y" cable until you mentioned an adjustable one. Never heard of such a thing. Could you provide more info?

Thanks,
Jeff

Carbon Fiber Pushrods for Split Elevator
 

Jeff,

I have bought them for JR servos, I'm sure that you could get them for Hitec also. I would check them out online or your LHS. They must have them.

Andy

Thanks to all
 

Thanks to everybody for all your help.

Happened to stumble across another thread that addressed mixing channels 2 and 7 on my Hitec Eclipse for dual elevators.

I am going to dump the "Y" pushrods and go with dual servos. Wish me luck as this will be a new adventure!

Thanks again,
Jeff

Carbon Fiber Pushrods for Split Elevator
 

What size plane are you putting these on?

Carbon Fiber Pushrods for Split Elevator
 

Mike,
I'm looking to retrofit a slow-fly aerobatic P-51. It has the traditional wood dowel/steel rod pushrods that are sloppy as can be.
I also have a Kyosho Flip3D .40 aerobatic pattern plane due to arrive any day.
I also have a Graupner Extra 300S .60 scale aerobatic due to arrive the end of December.

The P-51 is going to be my first experiment in changing out pushrods over those supplied. I will make the changes on this craft in anticipation of the others arrival.

I am starting to rethink the CF pushrod setup because I will still be left with about 8" of metal rod extending out of the CF rod to the elevator. I think this extension of the metal rod is where all the "play" is coming from. Don't think replacing the wood dowel with CF is going to change that.

Thought maybe I'd try some of those Sullivan Gold-n-Rods instead.

Any more thoughts would be appreciated...

Thanks,
Jeff

p.s. I'm an old Marx Bro's fan myself and I love your Groucho quote! :D

Carbon Fiber Pushrods for Split Elevator
 

Here's two ways. you could use 2 nyrod outter sleaves with music wire running through them. CA several pieces (About 3/8") of Nyrod inner rod to the wire every 5 inches or so.

Or, with the CF rod method, attach the two wires to the rear by drilling two holes and putting the wires thru the holes with a 90* bend wrap them with thread and CA in place. It won't move side-to-side, but if you're afraid it will, glue a dowel in the end of the fuse to act as a guide rail for the CF rod.

Anybody used the Dave Brown Fibergalss set up??
 

Has anyone tried the Dave Brown Fibergalss pushrods. Looks alot like MinnFlyers CF diagram.

Can be set up as a "Y" configuration.

Advantaged/Disadvantages?

Cheers

Carbon Fiber Pushrods for Split Elevator
 

WOW! Thanks Mike,

The dowel into the end of the CF pushrod is a great solution. Thanks for the info and sketches.

Carbon Fiber Pushrods for Split Elevator
 

Jeff, regardless of which method you decide to use, consider joining the elevator halves anyway (if its not too late). Even with split pushrods or dual servos, a light wire joiner provides a little back-up for some control method failures. :)

Carbon Fiber Pushrods for Split Elevator
 

SilverEagle2,

I have used the Dave Brown glass pushrods. They work really well, and are easy to install. I try to avoid the Y setup whenever I can, but if it must be done, the Dave Brown pushrods are probably the easiest way to do it.

Carbon Fiber Pushrods for Split Elevator
 

Those Dave Brown FG pushrods look like a good setup. I took a look at them at both Dave Browns website and Tower Hobbies. No where can I find any tech specs on them mainly the I.D. and O.D. of the rods. Any body happen to have these measurements?

Also not sure if I like drilling holes in them as per the assy instructions.

Anythoughts as to their merit over (or under) using Carbon Fiber?

Dimensions
 

I.D. 6mm
O.D. 7mm

Or

1/4 Inch round O.D.

Cheers

Carbon Fiber Pushrods for Split Elevator
 

Thanks for the dimensions SilverEagle. Was thinking about using the DB end fittings (which are available separately) with Carbon Fiber tube.
1/4" CF tube is way spendy. Makes the DB glass pushrod setup might attractive.
Thanks again.