On Sat, 30 Jan 2010 17:58:32 -0500, Ernest Christley
wrote:

Stealth Pilot wrote:

the crush strength of the wood in the hub area is likely to be the
critical factor in selecting the wood species used for a propeller.


There's not a rule stating that you can't combine species. A lamination
of a harder wood on the front and back of the prop would improve the
props chances of survival.
But the expansion rates may be different enough to cause other
problems - and the CENTER would still compress.