Netters;
The topic of what wood to use to build a wooden airplane has always been a
hot topic. Studies reveal that douglas fir is stronger than spruce, but
slightly heavier. The strongest, most stable fir is old growth CVG: Old
growth means more than 10 growth rings per inch - it really has nothing to do
with age of the tree, and CVG means Clear, verticle grain.
If you examine any unit of lumber, you'll find some of the the boards have
more than ten rings per inch. That board could then be resawn, ensuring that
the rings are verticle, deleting the knots, and be used for aircraft building.
Since most mill-run construction lumber isn't dried, a builder would want to
season it until the moisture content is reducted to a minimum in order to
ensure that the fibers sabilize. And, of course, once the wood is built into a
airplane, it should be sealed so it won't reabsorb moisture.
I recall reading about builders who used douglas fir for construction of a
KR, and the added weight was less than 10 lbs. Therefore, I think using
douglas fir is a viable option for builing KRs...or any wooden airplane.
However, if you insist on using spruce, I have a KR-2s fuselage, built of
spruce, for sale right now...for only $150. Come and get it boys!
RV
