very deep brake settings on a vented canopy

[mostwanted 0]

i just read the article about deep brake settings on the basewiki. there is a passage i do not understand. i marked it as bold.

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Deep brake settings and forward speed

It is important to understand that a canopy which has just opened in deep brakes has very little forward speed — that was the point, right? You need to be aware of two side-effects of this.

First, a canopy with little forward speed is particularly susceptible to winds at opening altitude. Even a small headwind can push the canopy back into the object. See that bluff to your left? A small crosswind from the right could put you there quickly. Know your canopy’s forward speed on opening, and be prepared to pop the toggles quickly if you need to get away from something.

Second, particularly if you have set your brakes very deep on a vented canopy, you may find the canopy unresponsive to riser input on opening. A parachute needs horizontal speed in order for the controls to be functional.

http://www.basewiki.com/wiki/pmwiki.php/Packing/BrakeSettings

[base736 0]

An unvented canopy will stall before it sinks straight down. You don't want to be playing in that territory on opening. A vented canopy, on the other hand, will behave in a more-or-less friendly manner even when it's sinking straight down.

If your assumption is that, since the canopy isn't behaving oddly, it'll turn on a dime, you're mistaken in the second case. The difference in your response to a 180 (for example) is an important one. Speaking from experience.

... Doesn't mean such a brake setting is bad, but you need to be aware of the difference.

[TomAiello 25]

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Second, particularly if you have set your brakes very deep on a vented canopy, you may find the canopy unresponsive to riser input on opening. A parachute needs horizontal speed in order for the controls to be functional.

I'm not certain what's meant there, either. It seems to me that the warning would be just as applicable to an unvented as a vented canopy. Does anyone know who wrote that section, and maybe the author can explain what they meant?

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[MyTwoCents 0]

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Does anyone know who wrote that section, and maybe the author can explain what they meant?

The history of that page (all the wiki pages have it at the top-right) shows this to be written by Jason Cooper (BASE 736). He'll probably chime in here.

I wonder if that line of reasoning came from the generally accepted wisdom that a deep brake setting that works for an unvented canopy may be too deep when transfered to a vented canopy.

[base736 0]

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He'll probably chime in here.

He already has!
My intent was to point out that, whereas my understanding is that an unvented canopy will open unpredictably if its brakes are set sufficiently deep that it has no forward speed on opening, this has not been my experience with a vented canopy. Under a vented canopy, then, the jumper has a choice:

(1) Set the brakes so that the canopy has forward speed on opening. The good news on a 180: You'll be able to turn by pulling down on one riser. The bad news: You'll have to do so quickly, because you're flying toward the object.

(2) Set the brakes so that the canopy has no forward speed. The good news: You're moving with the wind. No wind, no speed toward the object. The bad news: Even a slight headwind will push you toward the object, 180 or not, and that turn on one rear riser will do nothing.

The jumper who has chosen (2) -- that would be me -- needs to understand that BOTH rear risers must be pulled down to get some horizontal speed (backward) before the canopy will turn (by letting one up), or the toggles need to be popped (particularly important for such a setting when being blown *backward*).

[d_goldsmith 1]

I didn't know that yamstrike video was you. I've had that video on my computer since before I started jumping. I just watched it again and the canopy looks familiar I helped Tom A hang it up to dry.

My blackjack is set with very low forward speed, and the riser turns work good (I don't have much to compare it to)

I've got this really hardcore group of gaurdian angels that need a free paid vacation.
~Dan Osman