Vented Pilot Chutes

[guest]

No response? Confirms the fact that I think your full of #####.

Let's see:

Let's assume your friend took a 2 second delay and then towed the PC for 4 seconds as you say. For him to survive, it must have been a building that had a minimum height of 850 to 900ft. Hmmm....

If he was slider down, that would have hurt like hell and surely done damage to his equipment or his skeletal and muscle structure.

If he was slider-up, why was he taking a 2 second delay slider up from a really high building.

Just a guess here, but your full of crap.

Go somewhere else troll!

[guest]

>No response? Confirms the fact that I think
>your full of #####.

When I read the original post I was as curious as you were, and your analysis seems accurate enough to me. HOWEVER, you should understand that not everybody lives on the left coast of the United States. Your posts came at 4:00 and 8:00 Atlantic time -- even assuming everybody checks the BASE board at work (which they don't), not everybody will have seen one before they see both.

[guest]

My bad... Posted too early in the morning and got the times all fu(ked up. Nevertheless, no response in 16 hours hardly shows the guy was trolling. I would like to hear more about the jump in question, though...

[guest]

Your right Jason -- I was jumping to conclusions pretty fast there. I just get aggravated by all the people on here that try to slam manufacturers and their products without any real evidence or relevant feedback to back it up.

On a seperate note, but somewhat along the same lines:

I can't believe the wave of new jumpers that are just convinced they know things that aren't even statistically possible. For example, I met someone the other day that is abosolutely convinced that you can take a solid 5 second delay at the Perrine with a round and still open at a safe height. The guy had 18 BASE jumps, zero round parachute jumps, and no idea how to configure a round parachute for a BASE jump. He had simply put the rig together at Eloy and the guy who taught him how to BASE jump (who has 34 jumps himself) told him he could safely take a 5 second delay at the Perrine with a round.

I told the guy that a 5 second delay was likely to split his ##### 15 inches wide. Luckily this spooked him enough to back off from the jump. Good thing, because it turned out that he had a full diaper on the round, no rubber-band on the apex, etc.

I just don't understand the wave of jumpers who have no clue about what they are doing and the increasing number of 30 jump wonders out there teaching people to BASE jump.

Ok, enough ranting and getting off subject. I'll go take my medication and await a response about this 4 second PC hesitation from a building.

C-ya!

[guest]

>HOWEVER I had a friend go off a B in front of me
>and towed a 42" vented pc for almost 4
>seconds(on video), He said he noticed it a
>little, [...]

This strikes me as more than a bit odd, too... After two seconds of PC hesitation I imagine I'd be shitting bricks. After four seconds I would hope to have been reaching back to figure out what the hell's going on for at least two seconds. "He noticed it a little" makes me wonder if WGH might be on the right track with his "trolling" comment.

More information would be excellent.

[crwper]

Where can I get a copy of this?

Michael

[guest]

What is meant by "non-PDA" and "annular"?

[imported_Tom Aiello]

Amazon.com: Parachute Recovery Systems Design Manual (9780915516858): T. W. Knacke: Books

--Tom Aiello
tbaiello@mac.com

[imported_Tom Aiello]

>What is meant by "non-PDA"

PDA is "Pulled Down Apex". Pilot chutes have the apex pulled down by the centerline. This configuration promotes faster inflation. Non-PDA means that the apex is fully extended, so inflation is slower. Unfortunately, most of the technical material available is on non-PDA rounds, as those are generally used as full sized parachutes due to the tendency of PDA rounds to oscillate when fully inflated and loaded.

I know that several paragliding/hangliding emergency parachutes are PDA rounds (as are several of those building escape rigs). I bet someone has done some wind tunnel tests to get technical data on them, but I haven't been able to find it. Can anyone help me?

This posting:

http://www.dropzone.com/cgi-bin/foru...gi?post=132976

has some comments on pulled down apex, and the rough requirements for PC construction. I believe Space posted this article somewhere on this board as well, but I can't seem to find it here.

>and "annular"

Annular parachutes are essentially ring shaped round parachutes (no center). Most of the photos I've seen of them have smaller rounds
("engagement parachutes") centered in the hole, although that isn't strictly necessary. A rough approximation in PC land would be a PC with a ring of mesh material halfway between the apex and the edge.

--Tom Aiello
tbaiello@mac.com