This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Jeez Ric. You go out on a limb=20 and end up riding a freight train. I have to agree with Sarah's physics. =20 Same force, less mass, more acceleration. That assumes a constant force, though. Basically if you speed it up, you push on it. If you slow it down, it pushes on you. So if things are decelerating, then you can get force out of the key lead. If somehow you could get it all moving and then stop pushing on the key with your=20 finger, then there could be enough energy in the key to continue to drive the hammer home. Not really how we typically play the piano though, unless you consider "striking" the key vs. other types of motions. But here's the real rub. She's got you=20 riding a train when you should be=20 riding a bicycle. =20 Let's do a little energy napkin sketch. =20 Energy of mass m moving at velocity v=20 is (m*v^2)/2. So if the key front is moving at speed=20 1, then a key lead halfway out is=20 moving at .5, while the hammer=20 moves at approximately 6. If the hammer mass is 10g and the=20 lead mass is 10g, then the lead=20 energy is=20 (10*.5*.5)/2 =3D 1.25 while the hammer energy is=20 (10*6*6)/2 =3D 180! That's a ratio of 1:144. So yes, any energy=20 remaining in the key when it=20 bottoms out is wasted, but by far most of the energy is in the hammer. And it would appear that adding=20 a key lead makes less than a 1% change in the TOTAL inertia (hammer inertia=20 is effectively much larger because=20 of the leverage involved). Oversimplified - should all be rotational - and neglects the inertia of the unleaded key, but I think it makes the point that the SW and SWR are far and away the most important components of the overall inertia. For better repetition though, you=20 still want low key inertia. That would appear - at least based on this example -=20 to be the chief benefit of assist springs. -Mark Davidson ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/23/6e/92/b5/attachment.htm ---------------------- multipart/alternative attachment--
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