7725 BID Warp & Fill

Saro Marcarian

If you go to Spruce's "RUTAN FIBERGLASS CLOTHS" at https://www.aircraftspruce.com/catalog/cmpages/rutan.php?clickkey=33652 and click on the "Bi-Directional 7725 Data Sheet" doc link towards the bottom, you'll be directed to https://www.aircraftspruce.com/catalog/pdf/01-00642.pdf - which seems to duplicate https://www.hexcel.com/user_area/content_media/raw/DSF_7725.pdf directly from the manufacturer.

To cut right to it, the Warp Breaking Strength is listed as 440 lbf/in while the Fill Breaking Strength is 360 lbf/in.  I tried to lookup references to this in our various communities and couldn't find any.  On any layup schedules specifying BID, I've never seen absolute orientation discussed.  Seems that there could / would / should be a difference.

What am I missing?  Is this gonna be one of a long line of emails / threads I'll regret?  (preparing for the long list of "shut up & build" responses)


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