Key Leads and Inertia

[Richard Brekne]

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Richard Moody wrote:

>
>     Balance is balance.  It is easy to see you can balance a key
> with three leads close to the balance point or one closer to the
> capstan.  If the balance is the same but one has more mass than
> the other, does it require more force to move more mass?      Is
> this line of thinking the reason why I almost flunked high school
> physics?   ---rm
>
>

Hi Richard.

This is the basic reason I asked about the compatiblity with the FW
specification. I cant see that it isnt, but since Stephen was on line
and mentioned it all I thought maybe he would mention something a bit
more specific.

The discussion so far seems to be divided two times into basic views.
First, those who view the inertia characteristics of more mass towards
the center of the key as a positive, and those who believe the less mass
the better. Second, those who seem to think that the lateral balance of
the action as a whole is meaningless (except at very low levels of play)
and those who think this lateral balance is important at all levels of
play. (I'm not even going to get into the hammer weight question as that
one is never going to get agreed on)

Like I said a few posts back, I am unsure about the inertia questions as
I havent looked so much into it yet, but a few things seem evident. But
as to the lateral balance, I think pulling up the "dynamic tire balance"
analogy again might help, this time in a sense that might be more
applicable to our piano action.

Take our tire and divide it into 88 evenly spaced segments. Make each
segment equate to the variance in static balance and bring the tire up
to speed. Most every action is so uneven thus that such a tire would
wreck the balancing machine. Heck, even the best actions would cause
some serious wobble.

This is what the pianist is playing up and down at high speeds and it
does not equate to any kind of action transparency.

Now do the same thing and static balance (with whatever action ratio and
hammer weight levels your heart desires) useing the FW quantity as the
basis for key leading. That tire is going to wobble for sure... but not
enough to even come close to wrecking the machine. Going further and
finding optimums for configuring the inertial effects of whatever FW
levels we use will improve the tires spin even more. Indeed, this is no
doubt what David was thinking when he started with his so called "tower
leading pattern", tho no doubt other configurations yeild eveness as
well.

Cheers

RicB


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


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