R,C&S question JD

[Richard Brekne]

Hi JD... this is actually a very interesting point you make here... 
someone needs to clear this up for me... querie below


    Now if we imagine one of your structures with a hypothetical board
    that is truly neutral and passive (not developing any compression or
    tension) then when you apply the down-bearing of the strings to the
    bridge, your ribs will be pressed downwards until the compression at
    the top of the ribs and the tension at the bottom balances the
    downward force of the strings and the system is in equilibrium.

    ......

    JD


What I see here is that in an RC & S board under downbearing load at 
anything near glue up MC, the ribs will be in the opposite condition 
with respect to which half of the rib is under compression and which 
half is under tension then traditional boards.  The panels probably 
reasonably significant compression will be due string load forcing it 
(and the ribs) down.  So the panel will be in somewhat similar condition 
to compression reliant assemblies... while the ribs will be in opposite 
orientation.

Taking on humidity then... the panel will come under more 
compression.... and the rib will readily comply since downbearing has 
loaded it in the aforementioned reverse order of usual... It will as one 
of the arguements against compression reliant assemblies goes... <<want 
to straighten out....>>  but this time it has the growing compression of 
the panel working in concert as it were.  Strikes me that there are 
several issues here that haven't been discussed in open forum. 
Interesting ones at that. 

Curious also about one thing... how much crown does an RC & S board 
usually have compared to a typical CC or RC board.  Does unloaded crown 
vary depending on how much compression is designed into the unloaded panel ?

Cheers
RicB