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Fiberglass push rod - where to get em

Old 02-05-2004, 03:00 AM
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ScaleME
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Default Fiberglass push rod - where to get em

I need some 48" long, stiff push rods with 4-40 threaded ends. Anybody know where I can find these? What are you guys using for long control rods and how do you recommend securing them within the fuse?

Thanks

ScaleMe
Old 02-05-2004, 09:40 AM
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dr_wogz
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Default RE: Fiberglass push rod - where to get em

Fiberglass push rods...

Well, you can get carbon fiber rods. Typically arrow shaft, or spars for kites. as for threadding them, fiberglass and carbon fiber don't thread too well!!! typically, you'd end them with a threaded steel rod, glued / secured to teh end of teh composite rod.

And they should be free floating within the fuse, as 'secureing them' would lead to binding.

You can't use Gold'n'rods or the Sullivan equivalent? they are rigid, yet somewhat flexible, and do require securing to the inside of teh fuse..
Old 02-05-2004, 08:38 PM
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Default RE: Fiberglass push rod - where to get em

I tried the Dave Brown product and was less than impressed using them in my application which were short runs. [link=http://www.centralhobbies.com]Central Hobbies[/link] seems to have a very nice product line although I've only looked at their ads. I'll use them next plane and see if they are as good as they look.

JESTER
Old 02-05-2004, 09:19 PM
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Default RE: Fiberglass push rod - where to get em

I can attest to the superb quality of the Central Hohhies carbon fiber push rods and titanium ends. I've been usin them for about two years now, and have had ZERO problems with their use, or in setting them up. As a matter of fact, the C/H carbon fiber rods have remedied some of the old control issues I had been having. There is NO flex or slop in any of my controls. The rods have been used on my planes weighing from 14 to 28 pounds.

If you use them, and follow the directions regarding the suggested type of adhesive for the inserts (JB Weld), you will not be dissapointed.

As far as aerrow shafts are concerned, look in the yellow pages under archery supplies.
Old 02-05-2004, 11:48 PM
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Default RE: Fiberglass push rod - where to get em

Thank you for the recommendations guys. Sounds like Central Hobbies is the way to go for a complete package, comapred to the fix-it-yourseld ends of arrow shafts or other rods made for other purposes. As I understand it, with such stiffness, there is no need to put a support inside the fuse. Do you think the weight of the rod (perhaps as long as 48") would make the servos buzz due to the load (at rest) at the end of the servo arm?

Also at what size of aircraft would you choose to go with a pull-pull rudder set up over a push rod? I am looking at only scale models no 3-D or heavy acro flying?

Thanks
ScaleMe
Old 02-06-2004, 09:28 AM
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Default RE: Fiberglass push rod - where to get em

I also use the Central Hobbies carbon fiber pushrods and like them very much. The
problem you are going to have is not the stiffness of the rod but how long it is. When
the pushrods get as long as you are going to have, they oscillate and vibrate a lot and
can break themselves or cause servo damage. It is called harmonic vibration. I think
you are going to have to support them somehow if you make them 48 inches long.
A better option might be to move the servos to the rear.

tommy s
Old 02-06-2004, 03:40 PM
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Default RE: Fiberglass push rod - where to get em

Pull/pull is another very good option IMHO but requires more pre-planning as to physical location. Required reading is information on [link=http://members.cox.net/bdfelice/Ackerman/ackerman.htm]Ackerman control system geometry[/link] so as not to overstress your cables.
Hope this helps,

JESTER
Old 04-29-2004, 08:35 PM
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Default RE: Fiberglass push rod - where to get em

I have a question about the central hobbies CF rods: I just received my order which included the MKD clevises and horns for the control surfaces and the NMP dual axis rod end for the servo end of the rod.

The bolt that goes through the rod end looks quite large to me (I got the 3mm version) and needs quite a large hole to be drilled through the servo arms. Do you guys use this setup? If so, do you use larger arms? I'm using Futaba 3004 servos, the installation is for a Tiger 60....
Old 04-30-2004, 01:44 AM
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FHHuber
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Default RE: Fiberglass push rod - where to get em

I get arrow shafts and use JB weld to insert 4-40 threaded rod. You can either insert a section of all-thread, or put a couple of bends in the unthreaded section you insert. (I always try to line up the part that comes out of the shaft to be ON the centerline of the shaft tube)

Stuff in a plug of wadded up tissue as you insert the wire appx 1 to 1.5 inch. Fill around the wire with the JB weld. Wrap the end with masking tape. You can peel the tape off in a day when the stuff is cured.

If you have a friend that uses a bow... you can get the broken shafts for free. These can almost always be trimmed to give a decent useful length of CF tube. If yuo don't have a bowhunter friend... talk to the local archery dealer and they MIGHT give you some shafts that are slightly dinged. (and you can even buy some good ones...)

I have not tried yet... But I believe (and will try an experimental one) you could add some mircroballoons to the JB Weld to reduce the weight. (It won't save much...)

******************

For fiberglass rod... I get bicycle pennants. Its a bit flexible for pushrod use though. Makes a GREAT leading edge for an RC combat plane.

******************

For that Tiger 60... the stuff you are using for the pushrods is a bit of overkill.

I'm using the STOCK pushrod from the ARF for my Tiger 60's rudder. (yep the light 2 mm with a dowel.) And its doing just fine. I flew the plane in Pattern Competition. The elevator rod ended up needing a couple of bends... (the rudder rod has NONE) so I made one of the above arrowshaft rods. I used a 4-40 ball-link with 2 mm screw holding the ball on the arm intended for a 1/10 RC car's steering at the servo and a GP steel clevice at the control horn. The elevator is rock solid.

I have an O.S. .91 FS II in the nose of this thing... definitely not playing with low power since it has unlimited vertical at 60% throttle.

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