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Old 10-15-2011, 05:36 AM
Scorpion Racing
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Location: Winter Haven, FL
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Default RE: Carbon Fiber Push Rods ??

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