Virtual Capstan

[Richard Brekne]

Ron Nossaman wrote:

> I don't really care one way or another. As I said, I'm not interested in
> building a mathematically accurate action model. This is an illustration of
> principal ONLY.
>

Ok.. correct me if / where I am wrong then Ron

In the example you give, the magnet uses an assumed 20 grams force for
illustration purposes. You describe how that pans out in terms of its net effect
on the key front by adjusting this number by the ratio of the keyfront/magnet
ratio divided by the keyfront/capstan ratio, AND by also adjusting this number by
the ratio of this second class lever which is the distance of the whippen center
to the center of the whippen magnet divided by the distance of the whippen center
to the center of the capstan. In both cases the results are added to the capstan
which are then adjusted again by the key ratio to arrive at the net DW at the
front
of the key.

An attempt at an ascci whippen and key to illustrate....

WC...........Cap.........WMag
                 Cap.........KMag........BR.........KFront.


20 grams x ((KMag,BW / KFront,BW) / (Cap,BW / KFront,BW)) yields the magnets lift
applied directly to the key

and

20 grams x (WC,WMag / WC,Cap) yeilds the net lift on the casptan by the magnet
force upwards at the whippen magnet. This is a negative number because we are
lightening the load on the capstan.

Since both of these quantities are applied at the capstan... the net result felt
at the finger has to be adjusted by the ratio of the key at the capstan.

A very neat way of viewing all net effects of this extra <<virtual capstan>>
through the eyes of the real capstan and corresponding key ratio.

I like it !

RicB




--
Richard Brekne
RPT, N.P.T.F.
UiB, Bergen, Norway
mailto:rbrekne@broadpark.no
http://home.broadpark.no/~rbrekne/ricmain.html
http://www.hf.uib.no/grieg/personer/cv_RB.html