Pulley system

[Michael Carter]

I don't need or use a dual yoke set-up, but I peruse quite a few mechanical and industrial supply catalogs, some as thick as Webster's Unabridged. And yes, I have one of those editions.

If I needed a dual set-up as many of you have, I would have devised and used a chain and sprocket system. This is a fool-proof transmission-of-movement method with no guesswork involved except for the length of chain you might need...and that can be determined and cut to length as long as you buy more than you need.

It may cost a bit more than the cable/pulley system, but it aleviates many of the frustrations that Radar (and I'm sure others have) is experiencing now with slippage and mis-aligned yokes.

There are also rack systems available for the real experimenter in all of us.

[QF6228]

I don't need or use a dual yoke set-up, but I peruse quite a few mechanical and industrial supply catalogs, some as thick as Webster's Unabridged. And yes, I have one of those editions.

If I needed a dual set-up as many of you have, I would have devised and used a chain and sprocket system. This is a fool-proof transmission-of-movement method with no guesswork involved except for the length of chain you might need...and that can be determined and cut to length as long as you buy more than you need.

It may cost a bit more than the cable/pulley system, but it aleviates many of the frustrations that Radar (and I'm sure others have) is experiencing now with slippage and mis-aligned yokes.

There are also rack systems available for the real experimenter in all of us.

We also went through the process of using chains and sprockets, problems we had were...
-The fine adjustment in the chain were hard to achieve considering the size of the links.
-considering the size of the 80mm piping that we were using it was hard to fit the chain and sprocket into and have it turn without scraping.
-actually finding sprockets that fit is hard enough
There was also allot of other factors that marius mite be able to mention that I can't think of right now. I'm sure chains could work well but in my opinion
pulleys are the way to go.
It sounds like your main problem may be at the top of your yokes........Apart from the help I received from Westozy I found this guys setup a great help to
Drop him an Email...

http://users.skynet.be/jcordon/cockpit/colonGal.htm

Damien

[Michael Carter]

Using the chain and sprocket solution may require a bit more engineering on the part of the builder for fastening or mounting methods of the components, but as I said in my above post, slippage is eliminated and alignment would be assured as long as guidlines for chain and sprocket selection are used.

Tooth and chain must be compatible. And a fine enough chain and sprocket selection will yield the best control without slop.

[Westozy]

Chain and sprocket - naaaaaaaaaaaaahhhhhhhhhhhhh! You are attempting to turn a 10k potentiometer which probably requires a pumteenth of a gnat's knacker of torque to turn. A 2mm stainless wire rope correctly fed around quality nylon rollers with a single turnbuckle and cable clamps attached to the yoke pulleys works perfectly. Lubricate all axles including the yoke axle. Leave the clamps loose, tension the wire with the turnbuckle lightly, (you don't need it as tight as a piano wire). When the yokes drive each other correctly, align both yokes horizontally and tighten the cable clamps to lock the yokes together. Fit a linear pot to the cable somewhere, my wires move 45mm to and fro so a 50 mm pot was perfect. I did this two years ago and have never had to recalibrate the set up, it does not slip or go out of whack.

Use the KISS principle for everything, I see so much over-engineering in our galleries where guys have worked 5 times harder than they needed to, some of it is awesome work and I applaud every effort. Just don't forget that you are making an oversized joystick.

I see I need to add yoke heads and column bearings to the Aerosim catalogue.

Capt. Gwyn (Mech. Eng.) Occasional drunk!

[marius]

On a personal level I found the feel of the yoke much better when we used a chain but you can throw KISS out the window with a chain setup. Its much harder to get right.

The cable system is the way to go if you want only a headache instead of a migrane while building.

[Tomlin]

I found that with chain and sprocket, you had too much slop due to the tiniest bit of play that was in each link. By the time the transfer happened, there was a good bit of delay.

[marius]

I found that with chain and sprocket, you had too much slop due to the tiniest bit of play that was in each link. By the time the transfer happened, there was a good bit of delay.

The trick is to get the chain tight and the right type of chain and sprocket combination. Westozy was right in saying that a chain is really not needed just to drive 2 pots.

[PaulEMB]

Hi all,

I just finished a link that uses the best of chains and cable - suggested by Dieter Jakob of Routech. Please, credit to Dieter for the ideas!

I used around 18 inches of bike chain around a nylon tension sprocket for each yoke axle, then connected using 2mm steel wire - this gives you the "fixed" part you need at the yoke, and the simplicity of cables, pulleys and tensioners at the bottom. - Probably would be better with two sets of tensioners, but - time will tell, after a few hours of use.

A few pics posted, plus a schematic of the axle, used by Routech for their 737 yokes.

In addition, I added hydraulic cylinders, in line, to give damping, and that nice, well, hydraulic, feeling.

I haven't yet tried in flight, as I'm still getting the interface wires connected, but both on the bench, and in situ, the yokes feel more "alive" than my previous version.

http://www.mycockpit.org/photopost/d.../yoke-axle.jpg

[QF6228]

Paul.
Those yokes look like a great piece of engineering, it go's to show with the right tool and the right skill you basically can achieve almost anything...

Damien