Vents outdated? (cross post from BJ)

[Tree]

There is someone over a BJ.com questioning whether vents/valves are useful. He "heard" from someone who claims to have tested the opening heights at the Perrine and determined that the opening height between vents/no vents was 6'. I'll call complete bullshit on this on.

First, who did the testing, and how were they able to measure opening heights within a few feet?

Second, opening height and height of a controllable canopy are 2 different things.

Third, if you have either experienced first hand, or seen a vented vs an unvented canopy hit an object, you know that there is no question that vents keep the canopy inflated much better. During a strike the vents continue to allow air into the canopy to maintain pressurization, thus saving your ass.

Another silly post brought to you by Bj.com. Remember, there are people out there who really believe this stuff. Hope they aren't on your next load.

[lifewithoutanet]

Additionally, if you could even get the right controllable environment to perform the tests, everything would need to be identical. That is you're not just testing vented vs non-vented. The canopies would need to be the same make/model, with the only difference being the vents. Same jumper, rig, etc.
I'm wondering which two (or more) canopies were used during these "tests".
-C.

[base935]

Yea. For what its worth, I don't understand how vents/valves can't make an incredible amount of difference. I'm one of the few who have a lot of jumps on an ZP Ace, ZP BJ, and a standard BJ.

The vents/valves, and more importantly, the ZP, makes a huge difference.

If only everyone with a canopy could make ultra-scientific reports on the internet, BASE would be safe! Oh, I guess there is the other site. Let's watch and read what the experts have to say...

[Blitzkrieg]

whatever... rounds are the best. they don't even need vents.

[stitch]

For what it's worth, I think vents vs. non-vents has a lot to do with canopy size, exit weight, and wingloading. A 140lb. jumper jumping a 240 canopy is less like to notice the difference in opening times, than say a 200lb. jumper jumping a 322.

I've jumped both a 310 Mojo and a Troll MDV 305 (322) in the same day and the vented troll was definetly flying faster.

I think, and have even been told at different intervals that most of these tests are done by jumpers using 240-260sqft. canopies. IMO the results are a bit skewed.

whatever... rounds are the best. they don't even need vents.

What about the one at the apex ?

[lcspx]

Originally Posted by Tree

There is someone over a BJ.com questioning whether vents/valves are useful. He "heard" from someone who claims to have tested the opening heights at the Perrine and determined that the opening height between vents/no vents was 6'. I'll call complete bullshit on this on.

First, who did the testing, and how were they able to measure opening heights within a few feet?

Second, opening height and height of a controllable canopy are 2 different things.

Third, if you have either experienced first hand, or seen a vented vs an unvented canopy hit an object, you know that there is no question that vents keep the canopy inflated much better. During a strike the vents continue to allow air into the canopy to maintain pressurization, thus saving your ass.

Another silly post brought to you by Bj.com. Remember, there are people out there who really believe this stuff. Hope they aren't on your next load.

I made the original post on bj.com I jump an ace and a blackjack. the person who told me this information is from a gear manufacturer most people use. i like my vents and i believe they will save my life when i wind up on a wall. so for those certain jumps, i will continue using my blackjack.

The tests were done with the same size, shape canopy, with exact same wing loading. one with vents, one without. same make/size pilotchutes, of course there are many unknown variables, say if one pilotchute hesitated a bit more than the other.

i didnt say that they were outdated technology, i just wanted to see what a bunch of internet base jumpers thought about it.

thank you, maybe someday we can be on a load together

[Zoter]

I've only jumped an unvented canopy a few times....most of mine are on vented canopies, so can't comment on those claims your manufacturer friend has made from that point of view.
But Ive seen plenty of openings on vented vs unvented canopies at all heights and I agree with Tree.....

opening height and height of a controllable canopy are 2 different things.

And this is where I see the main difference between vented/non vented.

Lets approach this from a different angle...
All things considered.....why wouldn't you want to jump vented canopy ?
Taking out the 'opening height' argument....whatever your view is ,I don't think there is any doubt a vented canopy increases your odds of a more favourable outcome in case of a strike.

Some may cite a 'con' of vented canopies being harder openings on longer delays....but personally...its not been a major problem, and definately something I'd be happy to accept for the better odds those vents are going to give me in case of a strike.

So why would'nt you want a vented canopy ....and in relation to your question.....if they are out dated...what technology is replacing the benefits they provide..?

[nicknitro71]

why wouldn't you want to jump vented canopy ?

Because there are some people who jump relatively small canopies so the added benefits of the vents are not worth the degradation in flight characteristics and flare/swoop power.

I don't think there is any doubt a vented canopy increases your odds of a more favourable outcome in case of a strike.

Plenty of doubts.

So why would'nt you want a vented canopy

Because I like to swoop and my Ace 240 with z-po swoops better than a BJ with z-po, yes I've flown both. With the BJ when you transition from rear risers to toggles the thing just wants to settle down while the Ace keeps you in leveled flight a little longer.

Also vents work better on shallow trimmed canopies. Vents on a Raven/Mojo will not do any good.

There has been a shift in the trend from steeply trimmed canopies to more shallow with vents. Also the wingloading nowadays is ridiculously low so the vents do help pressurizing un-tensioned nylon. I see people my size jumping 280s all the time...what the fuck? If you cannot land on a dime at .7, stick to skydiving for a few more years, or for life. BASE is idiotic, canopy skills are not.

More importantly, know your tarp, vents or not. Go out and jump more.

[lcspx]

Originally Posted by nicknitro71

Because I like to swoop and my Ace 240 with z-po swoops better than a BJ with z-po, yes I've flown both. With the BJ when you transition from rear risers to toggles the thing just wants to settle down while the Ace keeps you in leveled flight a little longer.

same here. my ace swoops definitley farther than my blackjack...
my blackjack was my first canopy. i learned alot with it, and will surley be the next canopy i buy. i got the ace cause its the same wing without vents, figured i already knew how to fly it. only a couple differences.

last night i jumped both canopies back to back from 1800' of A. i took 13 seconds with my ace, large mesh slider,36"ZPV. on opening, i was immedieatley on toggles, turning 180. it definitley wasnt ready to fly yet, with an end cell or two still closed on each side.
load 2 i took 12 seconds with my blackjack, small mesh slider, 34"ZPV. opening was about twice as hard as the ace, producing the familiar grunt while saddling out. i was immediatley on toggles and i noticed it made the turn right away, unlike the ace. in those first few seconds of being open, i believe my blackjack flies better.
both are 240's, my wingloading is .75

1800' As are loads of fun!

Originally Posted by Tree

Another silly post brought to you by ME. Remember, there are people out there who really believe this stuff. Hope they aren't on your next load.

Another silly post brought to blinc by Tree



i dont think it's silly, if a manufacturer is planning to not push vents anymore. thats a big change




Thank you,
-Lane

[Zoter]

I don't think there is any doubt a vented canopy increases your odds of a more favourable outcome in case of a strike.
Plenty of doubts.

Elaborate and qualify please.

Are we really suggesting vented canopies are a bad idea as they stop us 'swooping' our BASE canopies as well ??
I'm sure they do.....but I'd suggest its a minority of of jumpers, that this really is a credible issue with.

[lcspx]

Originally Posted by Zoter

Are we really suggesting vented canopies are a bad idea as they stop us 'swooping' our BASE canopies as well ??
I'm sure they do.....but I'd suggest its a minority of of jumpers, that this really is a credible issue with.

As stated in my above post, I think my vented canopy has better flight characteristics sooner than my nonvented. yeah, the nonvented swoops better, but thats for big open field antennas and bridges. when it comes down to a building or cliff, with a tight landing area, I like my vented canopy better, cause i can almost immediately control it.

[Zoter]

yeah, the nonvented swoops better, but thats for big open field antennas and bridges.

Sorry...It seems we are clearly on different wavelengths when it comes to priorities in BASE jumping/BASE canopy control.
Soooo
I'll step out of this thread right about.....just after saying ...
'I' cant think of a crucial reason why I would electively choose a non vented over a vented canopy.
Its been working pretty good for me so far, so until I do see a good reason ( and BASE swoopin' aint one of em)....I'm sticking to vented.

[lifewithoutanet]

Originally Posted by Zoter

'I' cant think of a crucial reason why I would electively choose a non vented over a vented canopy.
Its been working pretty good for me so far, so until I do see a good reason ( and BASE swoopin' aint one of em)....I'm sticking to vented.

Ditto that. But if anyone can absolutely convince me that I'm wrong in this thinking, go for it. I'm all for being proven wrong and convinced that I should be doing something else because it's better, safer, etc.
-C.

[nicknitro71]

In short, if I can't hook it, I ain't jumpin' it, for real, and that goes for tandems too.

Out of here, gotta go sinking rounds...

[hamsandwich]

There's a lot to be said for a canopy that doesnt need vents to pressurize. For my style of jumping I've never felt I 'needed' to have vents. In fact all my sketchier jumps I've used a Mojo. Who wants to go terminal with a vented canopy too, not me. Vent's have there role though, some canopies require them for them the canopy to inflate properly, on others its augments and if I were the kind of guy to do low freefalls then I would want a higher loaded canopy with vents.

The ZP composite is this shizzzzzznozzzzz though. Adds so much life to the canopy. All my new canopies will have zpo leading edge.

ps- at the hospital with moose and steph, i'll post on teh other thread.


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