compound curves in plywood

"BA-100" wrote in message ...
"W P Dixon"
:

Luthiers commonly steam wood and form it over jigs, clamps hold it in
place until it drys out. May be the same kind of construction used to
build this sailplane. Just a thought and maybe something to check out.


Yes, I've done this in fact. Have a guitar and a violin under my belt, but
no compound curves. Most flattop guitars have a small radius which is
compound, but nothing like what I'm talking about (a complete teardrop)
This sort of technology realy died out when fibreglass hit the scene,
though i'm sure there are some masters still around.Most likely source of
info are boatbuilders, of course, but their curves wouldn't even appraoch
the radius I'm talking about.....

The key to bending wood with steam is how hot it is. Superheated steam is
best, which takes a re-heater after the water is boiled. Make sure the
plywood is made with water proof glue, which is anything of A grade or
better, or marked withEXT after the grade. It might be B grade, but I don't
remember, right off.

For testing, that type of plywood is fine, but for building a plane, use at
least marine grade, and best is aircraft grade.
--
Jim in NC