Renner "Turbo Wippens" ?

[Bill Ballard]

At 9:28 AM +0000 10/12/98, David ilvedson wrote:
>BW=(DW + UW)/2...What does that show us?  I am not particularly
>up on Stanwood's "balance weight" work.  Was there a recent
>article in the Journal I missed?  With a 50 gram DW and a 25
>gram UW we have 37.5 BW which I would assume is a good balance
>weight?  With a 60 gram DW and a 30 gram UW we would have a 45
>gram BW.  A 60 DW and 20 UW would be 40 BW.
>
>Thanks in advance...

You've got the math right. The Balance Weight concept was the first element
in David's extremely useful system of action analysis (or as he puts it,
"metrology). Actually the concept had popped up once or twice before in the
PTJ before he proposed his ideas in the 11/90 PTJ.

The essential assumption is that if the resistence which we read at the
keyfront with gram weights were 100% mass related and 0% friction, the DW
would equal UW. As friction grows (and by varying accounts it should run
16g @ #1 to 10g @ #88) the DW and UW should spread apart from each other
symetrically. The reason  for this assumption is that we need some way of
separating mass and friction in our diagnosis and treatment of action
problems. This may be a crude assumption, but the alternatives are either
nothing or rocket science.

BW is the first step in a very carefully structured analysis, which has
been well documented by David, both in the PTJ and at Convention Classes.
As for me, don't give me a DW or an UW. Give me both: I'll convert them to
mass and friction figures and be on my way.

Bill Ballard, RPT
New Hampshire Chapter, PTG

"No one builds the *perfect* piano, you can only remove the obstacles to
that perfection during the building."    ...........LaRoy Edwards