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Old 09-13-2007 | 06:58 AM
  #17  
da Rock
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From: Near Pfafftown NC
Default RE: Servo arm selection question - ?

starfire73,
Lighter pushrods are worth the effort. But then, anything lighter is worth any effort anyone is willing to put into the quest. Not willing? Don't do it. Like the challenge? Makes the hobby more fun for you. And this hobby is fun.

As for lighter pushrods.............
We want "lighter" and don't want to lose stiffness.
So I've been doing something special for the models that I think are worth the effort (and expense). Been using carbon fiber tubes. Epoxy shortened metal lengths of 2/56 size pushrod into the tubes. I found a tube with an I.D. that fits the metal rods. There were a couple of issues, but I think I got 'em solved.

First off, the CF tubes seem to have a plastic like finish. Not a problem for the outside, but it bothered me about the epoxy getting good purchase on the inside. So I lightly scrape inside before gluing. The metal goes in about 2 inches. And I use 30minute to insure good grip, but more about the epoxy in a minute.

Second, if CF tubes have a weakness, it's that they can be split. Not a lot of chance of that, but I'm covering new ground and don't like to take chances. So I originally wrapped the ends with epoxied thread to clinch the tube. The thread was wrapped over the metal ends to provide overkill for holding the rod and end together. It was labor intensive. I found a better way.

Turns out the rods are about as rigid as anything can be. And they're lighter than arrow shafts by a good margin.

And there are a number of plastic tubes that fit over the rods for support within the fuselage. Some are as slick as the CF rod, so there will be no wear. If the rods aren't bowed, there won't be wear anyway.

Recently, I've found a better way to do the ends. But overall, I've got what I want. Overkill stiffness. Overkill lightness. Easy to make. Installation looks clean and is clean.

Costs me about $4 for parts for each rod for my 40size. Worth it to me.

You might want to do something like this next time around.