RC&S question JD

[Ron Nossaman]

> * I keep trying to make this point: we should all be including the span 
> with our crown data, without which the data is absolutely meaningless! *

Which is why I talk about crown radius rather than crown 
height, and stick with generalities until everyone understands 
the basics, which apparently isn't yet the case, before 
charging off unarmed into the waiting swamp of details.


> *Further, if we can't predict this sag, we can't predict the dynamic 
> bearing and angle of string deflection, which means we don't know the 
> pressure and are going to have a rough time of making any rib scale that 
> isn't a shot in the breeze.*

Who says we can't predict rib deflection? One of the first 
things I did after Del ruined my life by getting me interested 
in this stuff was to build a spreadsheet for designing ribs 
from the string scale. Calculating deflection against bearing 
load is exactly how I design rib scales. Works out pretty 
close in the piano after it's built too.


> *BTW, while I don't make CC boards anymore,  I did apprentice in a shop 
> for several years that made about 20 CC boards a year and I have to say 
> it was like being in the Wild West. We were total cowboys. The only 
> thing we paid attention to was emc (3.5%). Rib dimensions came right off 
> the old board, the compression crowning was all over the place depending 
> on the time of year and size of the panels/ribs, and we set distance 
> bearing with the spare change in our pocket. Yee haw! Boy were those 
> days fun and also one of the reasons that I'm so compulsive now. :)*

And the reason those of us building RC&S boards have spent so 
much time accumulating and trying to pass on this information. 
We as builders think it's time to make an attempt to get 
control of the processes and produce a less random product.

Ron N