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I was discussing something in an email last week and after thinking about this, I'm a little confused. The more I think about it, the more it confuses me. Maybe you can help me see through my brain fart.

I own a canopy and I have the deep brake settings dialed in perfectly for my exit weight. If I let a lighter jumper use the canopy, and he uses my deep brake setting, what will happen?

Will the lighter jumper experience a stall because he is loading the canopy less?

With the same brake setting, will a higher wingloading result in a faster forward speed?

The heavier the jumper, the deeper the brake setting?

I would be curious in hearing the answer to this question, as well. Or not in an attempt to hijack the thread, just info on DBS's in general. I imagine the setting is on a curve, cause if you get someone on both extremes (a light and a heavy guy) it's hard to follow calculate things like wingloading, deepness of brake setting, etc etc, because more often the canopy's dimensions and characteristics are attributed to how its flying. That might not be clear, but that's my gut feeling, there's not a linear chart you can plot brake settings on. I think it also depends on what you're jumping, correct?

I just want to spur on some talk from more experienced folks

I would have to say that the lighter jumper (how much lighter?) on your DBS will be more prone to stalls and unpredictable openings simply because of the fact that canopies need that suspended weight (correct suspended weight!) below them to function properly. To little or too much and they start to act eradically. The lighter jumper making jumps on a canopy that is larger will have to set the brakes at a shallower setting (steeper glide angle) to "ram-air" faster into the canopy in order for it to pressurize and be more controllable quicker. This results in more of an undesirable forward surge. If that jumper uses the DBS, then as it tries to pressurize (gulps air) the wing loading doesn't remain constant and the flatter angle of attack (slower forward speed) will hinder the "ram-air" characteristics that cause these funny deceleration devices to fly. That being said I also believe that the new vented, valved, etc. canopies don't require a DBS and are less likely to stall on opening because the initial air is coming from the bottom and not the front. That means it doesn't need forward speed to pressurize like normal "ram-airs"
Bottom line is... jump the proper wing loading with the right brake setting and don't let people borrow your rig. It might end up being more hassle and danger than it is worth. Plus what happens if your buddy gets busted with your gear?? Is he paying for it?

Just my thoughts, which could always be wrong
570

I'm not actually letting someone use my gear, I just couldn't come up with a hypothetical reason why I would suddenly lose 15 or so pounds.

well i can while i have got 15pound on my belly just this year.. so im going to lose them again

Here's how it works:

I weigh 225 pounds at exit (plus rig).

Someone else, oooh, we'll call him "DW" for argument's sake, weighs alot less. Hypothetically, 160 at exit (plus rig).

DW is jumping a 245 Troll, and trying to snake an extra jump (hypothetically), he leaves it in line at exit point.

As soon as he jumps his other rig, I put the 245 Troll on and jump it. What happens, assuming DW had the brakes tuned properly for his bodyweight?

On opening, I have MORE speed than DW - the lighter jumper. This is both MORE forward speed and MORE downward speed - both vectors increase with the increase in suspended weight. This is true both before I pull the toggle, and after I pull the toggles. Logically, it must be true - with more mass to control and the same wing, the only variable that can change is vector speed.

Again, this is true both before I pop the brakes and afterwards, as well.

Thus, if I am going to snake, err, "jump" DW's Troll safely I need deeper brake settings. This will cut out the forward speed, converting it into DOWNWARD speed on opening.

So, with my properly-set deeper brakes I will be stalling faster down than DW would with his properly-set (shallower) brakes. Once I start flying, I'll fly faster under this canopy than DW (or any lighter jumper) will.

I owe this explanation to Ray L. as he first explained it to me in a way I could visualize.

This is why, ceteris paribus, a heavier jumper faces more dangers in BASE than a lighter one. We can't upsize anywhere near where DW can jumping a 265, and on even the biggest canopies we'll be flying faster - and stalling down quicker, than smaller jumpers.

Additionally, during super low freefalls we have more accelerating mass to decelerate on canopy pressurization. We also need bigger canopies, which are heavier to extract from the packtray. We decelerate slower as a result of both factors. Thus, a freefall from even 180 feet can be comparable to a smaller jumper doing 160 or so.

I owe this explanation to Dwain himself, and I probably owe him several avoided broken legs (or worse) for reminding me that huckin' my big butt off really low (150-160 feet) stuff freefall is way more unsafe than the same jumps for someone who weights 30-40% less, fully-loaded.

Then again. . . I get hassled alot less walking down the steet than smaller folks do ;-)

Peace,

D-d0g

So if DW threw on your rig which was tuned to open slose to a stall with little forward speed, since he is loading it less, he's going to open in a stall right?

The canopy isn't loaded heavily enough. In order to jump your canopy, he would need to move the deep brake setting down on the control line. Is this right?

Yes, that's correct - his weight isn't enough to cause the wing to fly forward - it's just going to stall down, not fly forward. The suspended weight needs to be enough to both pressurize the canopy, and to cause it to fly forward, as a wing.

I do suspect that beyond certain weights this relationship breaks down. Such as, take 500 pounds and put it under a canopy with the brakes set. What happens? Dunno, but it might not be the same thing that happens in more reasonable weight ranges.

Ditto, put 20 pounds under a canopy and it won't even pressurize correctly.

Peace,

D-d0g

I believe the parachute in question is more tuned to your body weight than it's original owner.

C-ya

Ha ha ha ha... You nailed that one dude.

I'm just trying to comprehend the logic here. After sitting and thinking about how the canopy would act deployed with different brake settings near the stall point, I managed to confuse myself. I'm pretty sure I understand it a lot better now.

Sorry there i lost it then..Why would we then set personal braks if its the same?Meaning then the manufactor could find the canopis stallpoint and set it there and we would all be the same..
But thats not what happen.We all find our own breaksettings(or should).This would be to find the stall point at excatly of the canopi and the jumper who jumps it.
Please tell if i misunderstanded somthing then..

I'm by no means an expert at this, but I think he was talking about personally finding your own DBS. Don't BASE canopy manufacturers suggest DBS, but the settings are usually not followed exactly? From what I gathered, manufacturers are not going to set down in stone how you set the brakes on your canopy, they leave that up to the jumper, due to every jumper being a different weight, size, etc, therefore one setting would be worthless *and potentially dangerous* to the buyer.

oh i see my bad english playing here sorry