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Tomlin
08-28-2007, 09:14 AM
Gwyn,

Back a few years ago I built some yokes and an interconnected yoke column system for my then B737 project and after trying both cable and bike chain, I gave up because I had too much flex in my columns and I couldnt keep the yokes synch'ed up with each other. In retrospec, I see that there are much better ways to build these than with the method I did.

I will soon modify my CH yoke and buy another one to mount on some new columns that will be a steel interior skeleton/cross over and have the pvc only for looks. On your site you mention the following:

"THE SMALL PULLEYS ON THE BACK OF THE YOKES ARE EACH FIXED TO THE WIRE ROPE." at http://aerosimsolutions.googlepages.com/22-Rollpitch--yaw-linked.jpg/22-Rollpitch--yaw-linked-full.jpg

What do you mean exactly by being 'fixed' to the wire rope? Do you mean that the cable/wire rope is somehow looped thru a 'yoke' of sorts mounted on the shaft of the control yoke, or that it simply rides over the top of the pulley and is a continuous loop of wire?

Also, is it possible to take a picture of how the wire comes across the top of the pulley where the yoke shaft meets the top of the column?

The system I built sound exactly like yours in the way the cable is ran (I think) but I used PVC alone for both the column, crossover bar, and had no bearings in the entire system, causing waay too much friction. Ive learned that lesson.

Thanks for your help and response!

Michael Carter
08-28-2007, 10:52 AM
You can buy Teflon sheet or strips from McMaster-Carr that will virtually eliminate any friction in your set-up.

Westozy
08-28-2007, 10:56 AM
Hi Eric,

Here's a pic of the back of one of my yokes http://www.mycockpit.org/photopost/showphoto.php?photo=825

There is a continuous wire rope (2mm) going around the pulley system with a small turnbuckle for tensioning adjustment. At the top of the yoke pulley, you can just see the locking device. It is a small brass electrical connector with a screw that 'bites' the wire. This electric connector fits into a notch cut out of the pulley thus locking the wire to the pulley at that point. This transfers the motion to the other yoke and makes it easy to synchronize the yokes. All the pulleys were from some old gym equipment and turned out to be ideal for the job. They work fantastic and are very smooth in operation. The resistance to roll motion is governed by the tension on the turnbuckle.
If you check out my albums there are over 150 pics of my sim with loads of detail that you might not have seen before.

With this method PVC is fine, you won't need steel in the column structure. Use my "torque tube" idea to link pitch motion, there is no flexing other than how much 800mm of 2" PVC can bend.

Regards, Gwyn