Hi all....

Not sure this is the best forum to ask this...but what the heck.....

What I would LIKE is a SIMPLE way to control the speed/feed rate of a cable
....(that and a winning lottery ticket)....

Now this control doesnt have to be very precise.....its just that id like to
have a mechanism that sets the upper limit at something like say 20 feet per
second.....and its even okay if this thing locks up for a bit if the speed gets
tooo high.....

So, one idea I have is to run the cable around a cylinder....from maybe half a
wrap (more like a roller then) to say one full wrap...

So, lets say that inside of the cylinder that the cable rubs against is an
inner rod...so now we have an inner non rotating rod and an outer rotating
cylinder that the cable rubs against....and for now lets assume that the
coefficient of friction is high enough that the cable and outer cylinder DO NOT
slide with respect to each other as the outer cylinder rotates and the cable
moves through our speed limiting mechanism.....

Now, if I place a viscous media between the inner rod and the outer
cylinder....that will provide a restraining torque? correct?

And will not the friction deposit heat in the media and the immediate parts?

And if I made the inner part with something that has a higher coefficient of
expansion....if the speed of the cable became too high the spacing between the
innner and outer parts should decrease and the "restraining torque" would
increase correct?

I guess my main question is.....what is the form of the equation for the
friction between 2 surfaces seperated by a viscous media?

Is the drag inversely proportional to the distance to the 1th power? the 2nd
power?some kind of exponential function?

Now it seems to me that if I balanced coefficients of expansion, the gap
between the 2, the specific heats, and the geometry of the set up that I could
get something functional......

Note that something ELSE would nominally be used to provide most of the control
on the cable feed rate.....id just like something that if the rate got too
excessive a postively restraining feed back loop would kick in on the order of
a second or so.....

Any feedback on other ways to do this?