Forums: Skydiving: Skydiving History & Trivia: Jumped a 55 year old 26' Navy Conical: Edit Log


pchapman  (D 1014)

Nov 18, 2012, 5:00 PM

Views: 2338
Jumped a 55 year old 26' Navy Conical

Yesterday I jumped a 55 year old canopy, a 1957 26’ reserve, a Navy Conical I think. Bill Cole and I think it probably was once one of his, that he dyed yellow as an attempt way back when to see if the dye would reduce porosity and descent rate. (I can't rule out that it could have been used as an airshow cutaway canopy later on too.) It has seen some service, with a replaced line and a bunch of patches.

Descent rate was about 20 fps down low, based on video timing vs. alti checks. Yes I was a little apprehensive! (When I did an alti vs. watch time check up high, I had blown through 1200' in well under a minute. Even without doing the exact math, I knew that didn't sound like much fun.)

The canopy was worn as a 3rd canopy on my belly, on a second harness. That way I could both watch the deployment and have no worries about chopping it if I didn’t like how it flew. But it did mean extra weight and a lump on one’s back when trying to land a round.

When a pilot chute has as weak a spring as an ancient MA-1, then it isn’t bad to have the canopy in sight while it deploys! The opening, after a 3 second delay from a C-182, was quick enough on video but at the time it seemed rather slow: I pulled the ripcord, nothing happened, I assisted in pulling open the flaps, the MA-1 bounced in the burble and bounced off my face, and “finally” – about two seconds later – started to pull the canopy away.

No wonder jumpers had to protect their Capewells when cutting away with a belly reserve in the old days.

The canopy sure flopped around in my burble as the MA-1 extracted it. One thing that was worse than even the old days was that elastics were on bights of line but not attached to the belly container's tray, reducing the little bit of staging that provides.

Canopy inflation was good, pretty symmetrical, with just a little extra dishing on one side (when looking at video frames). It's an undiapered round of course but with the low speed the opening wasn't hard.

“Rebound:” There was some good wake recontact after initial full inflation. It happened so fast I didn’t notice at the time but it’s clear on video. About a third of the canopy deflates and one line group goes all slack before second full inflation.

Canopy performance was poor, with seemingly very poor forward speed, despite having been "modded". There were 3 traditional vents at the back, which later had been meshed in too. I thought the mods would give good stability, but occasionally the canopy would randomly rock forward and back in an oscillation -- which suggests it wasn't consistently spilling air out the back and flying forward. Or perhaps even the slightest touch on the risers, to start a turn, might disrupt its normal flying and cause it to rock some seconds later. Not sure exactly what was causing the issue. Turns with rear risers were slow but worked.

The oscillation was not nearly as bad as what one sees in old videos of flat circulars, and only occasional. But it unexpectedly rocked back a few seconds before impact, so I ended up getting dumped on my back on landing instead of getting in the proper PLF I wanted in the low wind conditions. The impact wasn’t that bad but there was a little whiplash.

For those on facebook, a bunch of pics are at http://www.facebook.com/...855495656&type=3

For just a quick look, I’ve uploaded a few pics here.

I don't feel any burning desire to jump the canopy again; I think it'll be donated for a kid's room decoration next.


(This post was edited by pchapman on Nov 18, 2012, 6:16 PM)
Attachments: 1957 26ft - messy extraction.jpg (147 KB)
  1957 26ft - decent inflation.jpg (176 KB)
  1957 26ft - wake recontact on opening.jpg (58.0 KB)
  1957 26ft - Peter Chapman (Nov 2012) - oscillation on landing.JPG (222 KB)


Edit Log:
Post edited by pchapman () on Nov 18, 2012, 6:16 PM


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