RE: RE: Units of measurement?

From: Tim Goldstein <timg_at_ktmarketing.com>
Date: Fri, 10 Mar 2006 18:29:36 -0700

> Stiffness Coefficient is just that a coefficient, it is
> dimensionless.

Don,

Very good points and it does bring out that many people seem to
mis-understand the meaning and value of the scale.

What I have found is that for the range of balsa I deal in primarily, 100 is
about an average value. The adjustment I made was specific to thick sheets.
My experience over many thousands of sheets of wood is that unlike density,
stiffness is pretty consistent for a particular block of wood. I base this
on taking a block and cutting it entirely to the same thickness sheets and
then testing them. While the density will vary (sometimes considerably) the
stiffness coefficient for the wood from that block is quite stable. But what
I noted was that if I cut some .030" sheets from a block and then some .100"
sheets there was a great disparity in the stiffness even if the density was
consistent. More interesting was that the by handling and feel was a very
stiff and "snappy" piece regardless of thickness. My desire was to get the
scale more linear in regard to varying thickness of wood so that what by all
real world tests was a great sheet of stock would also have numbers that
reflected this in regard to using 100 as "normal".

Most important as you point out is if you use the same calculator it does
not matter as you are making relative comparisons.


Tim
[Denver, CO]
Indoor balsa wood & supplies
Now carrying Carbon Plate, rod, tube, and strip.
www.F1D.biz

Indoor flying info
www.IndoorDuration.com
 
Received on Fri Mar 10 2006 - 17:30:10 CET