Virtual Capstan

[Thomas Cole]

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Bob,

In your analogy, it wouldn't matter if you lifted the sack of 
sugar directly or by means of repelling magnets because there's no 
difference in leverage.

I believe the idea is not that the magnets are not supplying extra 
force, nor removing weight as wippen assist springs do, but that they 
are shifting the position of capstan and heel which changes the action 
ratio. Lower ratio equals less DW. It remains to be seen if  there is 
any advantage in actual playing. If Richard is getting favorable DW/UW 
measurements, and I don't doubt that he is, that's one thing, but it's 
only a theoretical point.

Tom Cole

BobDavis88@aol.com wrote:

> Imagine holding a 10-lb. sack of sugar. You feel it as ten pounds. Now 
> attach a powerful magnet to the bottom of the sack, and a powerful 
> repelling magnet in your hand. The magnets might not touch, but is the 
> sugar lighter? No. It might even float a few inches in the air, but 
> you still feel ten pounds of weight in your hand, the same as if it 
> were sitting on top of a coil spring which you were holding.
>
> This is because the magnets are part of the lever system. In order to 
> actually remove weight from the system, they have to be external to 
> it. This is true as well of springs. Wippen assist springs are 
> external to the system. Their  force acts against the support flange, 
> and in turn upon the [theoretically rigid] wippen mount rail. In order 
> for a pair of magnets to store potential energy in the deformation of 
> the magnetic field, one of them must be mounted outside the moving 
> part of the system; i. e., on the action frame.
>
> I think Richard should re-do his measurements.
>
> Bob D



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