Please can we call them cylinders
It is very possible, I just wouldn't recommend it.
Reducing the air will only reduce the amount of pressure and speed, the cylinder will still extend all the way.
A cylinder extends when air is applied on one end and exhausted out the other. To stop the piston inside the cylinder at a mid point you must stop the air from exiting.
That is how a flow control valve works, it is a one way valve that slows how much air comes out of the exhaust, slowing the movement.
So you must use a second valve (or a special valve) on the exhaust side to block the exit of air.
A easier and more reliable way to accomplish this is to put two cylinders back to back. Look at this pick from 1322. They are using three hooked together to get multiple positions.
http://www.chiefdelphi.com/media/photos/36233?
By far, the worst thing about it was the severe lack of cowbell. There was no cowbell what so ever. Had there been cowbell that would have completely changed everything for me. - Wildcat [more] 
03-02-2011, 07:44
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