Joggles and Crimps

[Lescombes]

Hello learned Forum regulars,

Long time lurker, first time poster... (sorry, couldn't help myself)

I'm looking at two charts from a company structures manual that are entitled 'Reduction in Crippling Strength from Joggles and Crimps'. They contain data on 4 curves: 1. Joggle, 2. Double Joggle, 3. Crimp and 4. Crimp and Joggle.

I'm reasonably confident that these curves are drawn from another source, and would like to elicit any suggestions that the brains trust may be able to offer as to which source it may be? At the conclusion of the chapter containing these curves there is an uncited Reference 5: N.A.A. Is anyone able to confirm the data is drawn from that manual? Could anyone go so far as to offer a chapter or page number if it is the case?

Many thanks,
Greg

 

[GrandpaDave]

Is the "N.A.A." you refer to actually the NCAA... maybe from some old 1930s, 40s, 50s, etc.? In those days lots of empirical tested data was collected and documents.
Check out Elmer Bruhn's classic text book which points to NCAA references.

 

[Lescombes]

No, the N.A.A. to which the document refers is North American Aviation.