<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html>   Bill Ballard wrote: <blockquote TYPE=CITE>At 12:35 AM +0200 6/20/03, Richard Brekne wrote: >The whippen assist spring simply makes the whippen lighter by >pulling up against it from the whippen rail. This really does >something quite different. It provides a secondary support for the >weight of the action very much in the same sense that the >capstan supports the action weight.</blockquote> Bill writes: <blockquote TYPE=CITE>Under Newton's Third Law (Action and Reaction), the support for the force opposing the lifting of the spring is the action frame. Under your scheme, the support for the force opposing the magnets is the pianist's finger and hand. It doesn't sound as though the forces encountered in playing this action have been reduced by transferring them to something outside of the system of parts in motion (pianist included).</blockquote> And  Mark writes <blockquote>This was my initial reaction.  You do less work at the front of the key but the same amount at the back of the key.  How's that possible? Yet he's got the experimental data to show it works.</blockquote> Well, first and formost, what is happening is that Im essentially increasing leverage with respect to weight only. The position of this << invisible capstan >> is important. Putting the magnets behind the capstan would make the action heavier at the key front.. The force pushes up as much as it pushes down. (again your Newtons Third). Thats why I call it the an invisible or <<virtual capstan >>. Thats what it functions like (a bit springy.. but thats not important because we havent removed the real capstan.) It very well splits the leverage components (distance and weight) into two independantly adjustable quantities. This works by changing weight leverage without changing distance leverage, to put it that way. 5 grams of balance weight  equates to 10 grams of front weight, or 10 grams of DW, or 20 grams of lead centered between the balance rail and the key front.  This is actually quite a decent range and and allows for a good deal of varying configurations. You can decide to take out 10 grams of FW from the key, or you can decide to move the standard capstan back for other touch considerations, or you can use it as a purely adjustble BW regulator... or some combination of the three for that matter. Its funny to watch really.. Take an action model and set it up as in the photo I sent. Configure it for 50 grams DW with the magnets as far apart as you can adjust them (13-14 mm or so). Then put a 45 gram weight on the front of the key and begin to screw down the whippen magnet so that it gets closer and closer to the key. At some point the key will just start to move on its own.   <blockquote TYPE=CITE>But if you don't intend to counterbalance more than 5g of BW, this could be negligible.</blockquote> <blockquote TYPE=CITE>Bill Ballard RPT NH Chapter, P.T.G. "I gotta go ta woik...."      ...........Ian Shoales, Duck's Breath Mystery Theater +++++++++++++++++++++ _______________________________________________ pianotech list info: <a href="https://www.moypiano.com/resources/#archives">https://www.moypiano.com/resources/#archives</a></blockquote> -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway <a href="mailto:rbrekne@broadpark.no">mailto:rbrekne@broadpark.no</a> <a href="http://home.broadpark.no/~rbrekne/ricmain.html">http://home.broadpark.no/~rbrekne/ricmain.html</a> <a href="http://www.hf.uib.no/grieg/personer/cv_RB.html">http://www.hf.uib.no/grieg/personer/cv_RB.html</a>  </html>