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| Spec ID | Title |
|---|---|
| MIl-C-7020 | Cloth, Parachute, Nylon |
Procedures
Gores
Block vs. Bias Construction relates to at what angle you cut the gores out the fabric. Advantages of block are: simpler fabrication. Advantages of bias are: better canopy strength, less line loading and less required slack. (Poynter 8.1.5 and 8.1.9)
Shroud Lines
From Knacke (6-84): "all lines and tapes are [traditionally] measured under a preload. A preload of about 1% of the ultimate material strength is required to align all fibers in the woven or braided material before the individual fibers are stretched." Furthermore, "[it] is practical to let all fabrics relax for a short period after rewinding from the storage spool before measuring the material."
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Full details on sewing standards can be found here.
Terminology
take-up: the shortening of two pieces of fabric around the seam. Ideal parachute design takes this into account.
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