Curiosity. . . . . . . .

[DYEVOUT 0]

I read a thread in this forum about guys getting pommeled on hard openings. I am still looking for rig #1, and jumping rental Mantas (AFF L12) - I've only been hammered once, and not to the degree you guys describe (just some bruising around the groin area, glad me berries weren't in the way).

My question is in regards to the mention of a pocket in the slider - I've never seen one. I've seen "windows" with mesh "screens" in sliders, but never a pocket. How does this slow the opening? Does it hold the slider up top for longer? Just curious. . . Any pictures?

----------------=8^)----------------------
"I think that was the wrong tennis court."

[Sonic 0]

A slider works but catching air - the pocket just simply allows it to catch more. It's almost like to sliders sewn together, but only sewn on 3 sides (the front is open). The size of the pockets can vary depending on the canopy and how the pilot wants it to open.

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It's like something out of that twilighty show about that zone

[councilman24 37]

Also realize that the definition of a "hard" opening varies from jumper to jumper. Many new canopy models are designed to take several hundred feet to open. I "grew up" jumping when if you had time to look at your canopy before it opened it was too slow. I demoed a Spectre shortly after they were available. Two terminal and two subterminal openings all took app. 700 ft to open. I call these malfunctions that finally cleared, but this is how the canopy was designed and is what many (most) new jumpers want. (New defined as 10 years or less in the sport) Getting out at 2000' this was a little long. (Flatline on my timeout.)

Actually I remember having to learn to slow down before opening. With my ParaCommander I used to open in a track.

What most jumpers consider a hard opening I consider a normal opening. Of course I'm an inch shorter than when I started 24 years ago. When original Ravens took as long to open as current canopies, we put bikini sliders on them to speed them up.

My current canopies are a Sabre and a Triathlon. Both open briskly, just the way I want. Especially getting out at two grand, or throwing out at 2500'.

Ram air canopies open two fast and must be slowed down to survive. Watch base slider down openings sometime. Some early system used the PC drag in various ways. Then the sail slider was invented. The air it catches holds it up and resists the spreading of the line and the opening of the canopy. This is a fine balance that also includes the particular design of the airfoil, construction, trim etc.

BTW the current article on base rigs talks about bottom skin vents being for advanced base jumper. My first ram air, a 1.5 oz per sq yard Strato Cloud, has bottom vents and no crossports (till I cut them).

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[cobaltdan 0]

if i didn't know better i would think you are joking about being shorter.

at the recent SAFE symposium (military parachute and safety equipment) where we exhibited i was able to meet several of our us military test jumpers from china lake. 2 told me that they are a documented 1 1/2 " shorter as a result of spinal compression from test jumping.

i though i was a test jumper unit i heard the incredible (crazy) stuff they test !

sincerely,

dan<><>
www.extremefly.com

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[riggerrob 643]

Two bits of advice:
First tighten your leg straps so they ride high in your crotch, firm up against your pelvis. That way there will be no slack for them to slap your family jewels.
Secondly, I have sewn slider pockets onto dozens of canopies, mostly Sabre Mark Is. Most slider pockets are sewn onto the leading edge, though Weird Wayne recommends sewing pockets onto both the front and back edges. If hard openings persist, Wayne sews pockets on all four edges of the slider.
Pockets soften openings two ways. First, pockets hide the nose for an extra split second, delaying cell inflation. Secondly, pockets increase the area of the slider, catching a bit more air and delaying its descent.

Slider pockets are mainly seen on early ZP canopies like Sabre Mark Is. Most of the canopies in current production are designed to open softly without pockets.
Sloppy packing is the most likely cause of a hard opening these days. People either forget to push their sliders hard up against the stabilizers or they get lazy when stowing rubber bands.