[apologies if this is a re-post; Google acted like it lost the first
one]

Earlier, Richard Lamb wrote:

I don't claim to have studied every design in the homebuilt arena,
but I can't think of a single amateur built design that calls for
ribs to be formed in O contition then heat treated.

I can name two: Pazmany PL-1 and PL-2.

Techniques for forming and straightening, and advice on obtaining the
tempering services, are described in the Pazmany book "Light aircraft
construction for amateur builders" available through the Pazmany web
site:

http://www.pazmany.com/books/books.html

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com