Simplified Wing Stress Analysis (10Mb PDF)
I Beam Analysis Good article on built up spars vs. solid wood spars. (2.5Mb PDF)
Strength of Metal Aircraft Elements (8.2mb PDF)
ANC-18 Design of Wood Aircraft Structures. It is split into 3 parts for easy download. I think this might be the first edition, for what it's worth my second edition is dated June 1951.
I don't have the complete ANC-19 in PDF but here are some information from ANC-19 concerning "Requirements for Wood in Specific Parts".
ANC-19 pg 118-126 (9.5mb)
Three PDF documents that can be used to determine the size and location of the large registration numbers on wings.
NACA report #344 regarding spar web design (PDF 1.2mb)
Build you own sand blaster By Chris Bobka
Summerill tubing data
ANC-5 Strength of Aircraft Elements 1940, this is a copy of ANC-5. It is the later revised October 1940 edition. As it is so scarce and is a companion of sorts to the Summerill tubing data pdf above. Thanks to Chris Bobka
More to come later..
Email me if you have any construction tips you want to share.