Friday, June 10, 2011

Proof of Concept -- Pressure Restraint Garment SUCCESS!

Now that the neck seal issue--a two-year long odyssey finally solved by turning my thinking completely black-to-white, and making the pressure in the garment work _for_ me rather than against me--is 'cooked', I'm on to the next issue; the pressure restraint garment. The PRG is a coverall that is slightly smaller than the pressure bladder, so that when gas is pumped into the suit, and it blows up, the mechanical load is not taken by the bladder itself, but the PRG, the tight coverall. I've wrangled this problem for a while, and tonight's proof-of-concept test showed that with some intelligent seaming decisions, I can in fact build the PRG on my own, by hand. Therefore I'll only have the Portland Garment Factory work on the final coverall, a fireproof, insulating garment with the various pockets and attachments needed for safe flight.

In the photos, I've started to cannibalize my paragliding flight suit--a simple coverall (I'll just get another one for flying...they're only about $40 at a surplus store)--into the PRG; at first, slipping the legs over the pressure bladder, then tightening the coveralls over the pressure bladder with hand seaming, and then inflating the pressure bladder and seeing that my simple seams hold the pressure handily.

When I learned to seam heavy fabric by hand, using artificial sinew and heavy needles, to build the sails for our 20-ton sailing raft expedition in 1998, I had no idea that that skill--a familiarity with needles, seaming palms, artificial sinew, how to manage textiles under pressure, and so on--would ever be used again. But here I am, using exactly the same materials and techniques for a very different project!

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