bunda@cs.utexas.edu (John Bunda) (04/24/91)
Leonard Moorehead, local skydiver/inventor, has come up with a process
for coating parachute fabric to reduce its permeability (or porosity
as everyone calls it). He had experimented with this on a couple of
canopies, and the owners of these were pretty ecstatic with the
results. One of his first experiments was on an old Firefly of mine
but it had been so long since I'd jumped that old rag, it was hard for
me to tell.
My Excalibur 135 has about 600-700 jumps on it, and was really starting
to lose its flare. I decided to experiment on it.
I knew it was badly out of trim, the inside A lines were about 2
inches longer than the ones at the end cells. So first, I ordered a
new set of microlines. I was surprised to see that all of my lines
had stretched from 1 to 3 inches. I jumped it several times after
installing the new line set; the openings were much smoother, but the
landings were not much improved, if at all.
Now I know that PD has tried building Excaliburs from ZeroP3, but they
found that they open too hard. Also, the coating increases pack
volume a little bit, and I was worried that the coated canopy might
not fit in my V1-2 Vector. Leonard offered to try a lighter coating
that would not reduce it to zero porosity, except for the slider. So
I went for it. The results:
The pack volume didn't increase noticeably - it is bigger, but I
didn't have to lengthen my closing loop. The fabric is slipperier,
and it's harder to pack, but since it's not quite zeroP, it's easier
than a Blue Track or Sabre. The openings - definitely on the brisk
side, but not nearly as violent or painful as when the canopy was new.
I can live with it. The big news is the thing now lands *much*
better, almost (but not quite) as good as new. It's really impressive.
He won't give details of the process, except to say that it is a
cross-link polymer similar to that applied to the ZeroP3 fabric
currently used on PD Sabres and Glide Path Ariels. The difference is,
he can apply it to an already-constructed canopy; he's got a huge
adjustable rack that he uses for this. Leonard is working on some
more improvements to the process, and may offer it as a service (price
undetermined right now, but he says definitely less than $200/canopy).
By the way, he also installed a Velcro-free slider collapsing system
he designed that works much better than *any* of the velcro-type
systems I've seen.
-John
--
John Bunda * bunda@cs.utexas.edu * {uunet,harvard}!cs.utexas.edu!bundaklox@otago.ac.nz (05/01/91)
In article <257@darkstar.cs.utexas.edu>, bunda@cs.utexas.edu (John Bunda) writes: > Leonard Moorehead, local skydiver/inventor, has come up with a process > for coating parachute fabric to reduce its permeability (or porosity > as everyone calls it). He had experimented with this on a couple of > canopies, and the owners of these were pretty ecstatic with the > results. One of his first experiments was on an old Firefly of mine > but it had been so long since I'd jumped that old rag, it was hard for > me to tell. Yowsa! Sounds like my saggy old paraglider could do with some of this magic! Any idea if he's going to market it widely? Cheers KLox