What's all this I hear about Inertia ? Nick G

[Richard Brekne]

Hi Nick:

    Nick G writes:
    Hello all,
    RE: RicB's statements:

    Clearly a change in FW changes the value of the entire left side of
    the formula, and hence the equivalent R on the right side.
    Review Stanwood's formula.   R = (BW + FW - WW) / SW  


The thing is that I've used this stuff for several years now, but simply 
dont think along the same usage lines that remind me that a change in FW 
automatically change BW by an equal and opposite amount. Its rather self 
enlightening really from a usage point of view... but easy to forget in 
a discussion like I let myself get into... a bit too tired and a bit to 
late at nite. The various objections raised to the above last nite were 
all correct. True enough... as you point out... looking at the formula 
above it does not reflect this fact and would seem to bear out my stance 
of yesteday... but we are supposed to know this by now and I simply 
blundered, hung up on the leader thread which had to do about replacing 
key lead with assist spring strength.

This said...

I stand by my statement that no direct relationship between the SW ratio 
and the distance ratio exists outside of the most general one that 
increasing one increases the other. But as David S illustrated in his 
post... you cant simply translate from one to the other without further 
ado.  It is interesting that he finds ground to assert there is some 
optimal ratio between the two ratios. I look forward to his published 
work on the matter when it comes.

I also stand by my statement that the SW ratio is a very different puppy 
then the distance ratio. The distance ratio can be directly measured by 
measuring the lengths of the relevant arms taking into consideration 
their respective relevant angles. Or you could simply measure hammer 
movement for key movement. Not so with the SWR since it removes the top 
action ratio entirely from the equation.  Again a review of my own 
Journal article on the subject

    Draft copy at :
    http://home.broadpark.no/~rbrekne/referhtml/touchweight.html

explains that quite well, and is accompanied by a bit of math showing 
how one can derive the SWR from the more simple combination of the three 
arms ratios... i.e. HR * WR * KR.   I would like to point out tho that 
if you have all factors for the SWR, you can not find the individual 
ratios for the HR and the WR... only what Stanwood used to call the top 
action ratio which is nothing more then the combined ratio of the 
whippen and the hammer shank.  I still am unsure what he used that for 
some years back and have not had the time to look much closer at it 
since I wrote that article.

I'd still like to hear more about the Geometric Balance concept that was 
tossed out by Greg I think....

Cheers, and thanks for the very agreeable posting.

RicB