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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A title=oleg-i@noos.fr href="mailto:oleg-i@noos.fr">Isaac sur =
Noos</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
title=eromlignod@kc.rr.com
href="mailto:eromlignod@kc.rr.com">Don A. Gilmore</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, December 22, 2003 =
4:34
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: Touch Weight</DIV>
<DIV><BR></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px">
<DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>Don, hello, I guess I get =
it.
</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>May I understand correctly =
that the
angular position does not change the static balancing or is it only =
m.o.i
that is unaffected ? (say that because wehn we change the attack =
angle of a
key we change leverage, I also wandered if there is some effect in =
regard of
the mass itself)</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>Well, I think I'm following you. We =
have the
term "static balancing" in engineering, but I'm not sure if it has =
the same
meaning as in your profession. We consider static balancing =
that which
balances a pivoted object when at rest. Let's consider a fan
blade. If a fan blade is out of balance, one blade will tend =
to sag to
the bottom due to gravity. When it is properly statically =
balanced,
you can rotate it to any position and it will stay; the center of =
gravity is
exactly at the pivot point. Static balancing is all about
<EM>gravity</EM>. [In contrast there is also "dynamic" =
balancing which
takes into effect rotation. An object can actually be in =
perfect
static balance and not be dynamically =
balanced].</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>The angle of placement of a weight =
<EM>does</EM>
affect its balancing properties since gravity is always in a plumb
direction. For example, if you place a weight three inches to =
the
right of a pivot it can counterbalance an equal moment on the =
other
side, like a scale. But if you place it three inches
<EM>above</EM> the pivot it doesn't balance anything since gravity =
acts
directly toward the pivot and there is no leverage. However, =
either of
these placements of the weight would result in the same moment of =
inertia,
since you have the same raduis and the same mass. Confused
yet?</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>Let's consider moment of inertia in terms =
of a
"black box" with a shaft sticking out of it. If you turn the =
shaft and
it is hard to start turning and then hard to stop (as if =
there
were a flywheel in the box), it has a high m.o.i. If it is =
easy to
turn (as if there were just a plain shaft in the box) then it has a =
lower
m.o.i. What the rotary object in the box looks like is
immaterial. It might be a round wheel, or it might be a hammer =
pivoted
at the base of its handle. But any two objects with the same =
moment of
inertia will feel exactly the same (neglecting gravity) when =
you twist
the shaft, no matter what they look like. Think of m.o.i. like =
"rotational mass". </SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>Balancing is affected by gravity; inertia =
is
not. If you took your black box to the moon, or out into
space with zero gravity, <EM>the shaft would be <U>exactly</U> =
as
difficult to accelerate and stop when you turn it as is was on
earth</EM>. The same is true of mass. A 275 lb. football =
linebacker may only weigh 90 lbs. on the moon, but he will hit you =
just as
hard if he tackles you there as he would in Green Bay, since he has =
the same
mass.</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003></SPAN></FONT></SPAN><SPAN =
class=488560419-21122003><FONT face=Arial color=#0000ff =
size=2><SPAN
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>Thanks for your analysis =
and words it
helps ! We piano technicians have generally a small undertanding of =
what
goes on in the action really ! On the contrary, some friends that =
studyed
accoustics and physics at a somehow interesting level said =
me that
their understanding was not really helpful when it comes to tune, =
regulate
and voice a piano !</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>Best regards and good late =
Christmas
shopping !</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>BTW, Are you the inventor =
of the "self
tuning piano system", or may is miss something ? if it is the case, =
I have a
few questions I like to understand some points on the process, if =
you don't
care.</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>Yes, that's me. I wrote an =
article in
the Journal about it in July 2002. The PTG asked me to join =
after
that. I would be glad to answer any of your questions (or =
anyone else)
about the system.</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
size=2><SPAN
class=062251422-22122003>Don A. Gilmore<BR>Mechanical =
Engineer<BR>Kansas
City</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003>Greetings.</SPAN></FONT></SPAN></DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN =
class=062251422-22122003></SPAN></FONT></SPAN> </DIV>
<DIV><SPAN class=488560419-21122003><FONT face=Arial =
color=#0000ff
size=2><SPAN class=062251422-22122003>Isaac
=
OLEG</SPAN></FONT></SPAN></DIV></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></H=
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