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BrianSGermain

New USPA Downsizing Chart proposal

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Brian,

Care to offer how some of the odd numbers for the minimum sizes were arrived at? As best I can figure out, but didn't try hard, they don't represent real world canopies that might be chosen.

Also, is this based on a particular measurement system? PIA vs PD vs various for ellipticals?

Is the intent to be part of the BSR's or part of the recommendations?

Just trying to understand.
I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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It's a chart, so it might be hard to get it paginated correctly using the forum software.
May I ask, in the vein of councilman24, but with a slightly different angle:
What's the derivation of the numbers? What makes a chart entry not one size bigger or smaller? What makes this table more correct than one with all values shifted to the right one notch? (and allowing the leftmost column to stay the same)
My advice is to do what your parents did; get a job, sir. The bums will always lose. Do you hear me, Lebowski?

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Brian, can you adjust the 110 exit weight to be more real world realistic and move towards a max min size of 97/105 by 500 jumps and 120 as the midline? I tend to agree that a 120 as max smallest for a little person at 500 jump is a little on the too cautious side.
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Brian, can you adjust the 110 exit weight to be more real world realistic and move towards a max min size of 97/105 by 500 jumps and 120 as the midline? I tend to agree that a 120 as max smallest for a little person at 500 jump is a little on the too cautious side.



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Helps on that side, but I'm failing to see why small jumpers are only able to get to 1.1 or so and large jumpers are up to 1.76 at 500 jumps if they go for the smallest possible. I'd think that 1.5 would be about the max on the upper end... am I missing something?
Yesterday is history
And tomorrow is a mystery

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How common is the 113 in the general public though? I know in the CRW dog world there are'nt that many of them just floating around and for the most part you have to have one custom made to fly one.



We've got a few at our DZ. But you have to be real lightweight to use them, a 143 is the most common size (here at least). Maybe more lightweights need to do CRW? :P

ciel bleu,
Saskia

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How common is the 113 in the general public though? I know in the CRW dog world there are'nt that many of them just floating around and for the most part you have to have one custom made to fly one.



It used to be that way. I had to practically promise my first-born child to PD to get one back around '96 or so, but there were at least 3 on the last record. There was at least 2 more people who could have been on 113's weight-wise but for various reasons jumped a 126 with weights instead. Of the last 4 people to dock on the 70 way, not only were all 4 small women, 2 of the 4 were jumping 113s, and 1 more could have been.

I've been really pleased at the growth of the number of women doing CRW. It was only 5 years ago that I was the only female at practically every CRW camp. Now there are usually 5 or more. As the sport grows, we'll get more and more women which will make this more of an issue. I think about 10% of the 85 way was women.

I remember when I first started doing CRW - (at 115 lbs) they had me jumping a Prodigy 175 with 30+ lbs of lead + gear. I didn't do very much of that because it sucked so bad and I went back to doing CRW on my Jonathan 105 (not a good plan, but I didn't know about Lightnings back then, and Spectres and Triathalons didn't exist yet.)

W

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Helps on that side, but I'm failing to see why small jumpers are only able to get to 1.1 or so and large jumpers are up to 1.76 at 500 jumps if they go for the smallest possible. I'd think that 1.5 would be about the max on the upper end... am I missing something?



Parachutes of the same design and the same wingloading will not perform the same in different sizes. In other words, a 120 is much quicker than a 170 even at the same wingloading.

Smaller canopies turn faster due the the shorter lines, and have a diminished glide ratio due to the shift in the balance of drag between the jumper and the canopy. Further, size is scaled based on canopy AREA, which is a square function, while the VOLUME inside the canopy (airfoil drag) needs to scale as a cube function. In other words, when we scale a wing down based on the scale factor generated for the area, the internal volume reduces at a greater rate.

Bottom line is, small parachutes can handle less wingloading if they are to perform in a similar manner.
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Parachutes of the same design and the same wingloading will not perform the same in different sizes. In other words, a 120 is much quicker than a 170 even at the same wingloading.



They will definitely _turn_ much faster but their forward speed is much slower. So its a trade-off - both can kill you.

On the large CRW formations, the small canopies are always on the outside. That's because they are so much slower than the large ones. The big boys are up top and down the center because they're hauling ass... And having watched a lot of crash landings on Lightnings of identical wing-loadings but different sizes, the big boys look like they hurt more - most likely because of the extra speed and mass...

Its a trade off though - a big boy can go to an elliptical when he wants to go "twitchier" but a small person already has twitchy but usually wants to go smaller for speed...

It really is interesting watching how the relative canopy sizes in an environment when you know everyone is practically identical on the wing-loading. Everyone can smoke past me in speed, but I have much more minute control because it takes so much less effort to get my canopy to move or turn.

This chart seems to not taking into account the greater forward speed of the big canopies (which can definitely kill ya) and placing all the blame for canopy problems on the twitchiness. A few months back I watched a guy loading a 190 square (Sabre 2 maybe?) just a hair over 1 smoke past me under my 1.5 loaded 99. I think the forward speed is more likely gonna cause injuries than the fact that the smaller canopies turn faster.

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We're not talking at 50 jumps here. The charts wouldn't let them jump a 1.3 wing loading at 500 jumps! There's a HUGE difference between 50 and 500. And heck - the big boys can load at something like 1.7 on this chart.



Plus full time CRW folk tend to have a ton more canopy time than freefallers - accounting for more experience at a quicker pace.
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you can burn the land and boil the sea, but you can't take the sky from me....
I WILL fly again.....

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okay so according to that it states I can be at a 170 to a 150 according to my jump numbers, but since that would be a drastic downsize (im anywhere between a 190 and a 200 still because I like a forgiving fall) does that mean I need to be weaned into the 170 and such... since I am used to the bigger one? I have no plans to downsize for awhile but I am curious...
Sudsy Fist: i don't think i'd ever say this
Sudsy Fist: but you're looking damn sudsydoable in this

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Brian - will there be more than just the chart released? I'm of the opinion that some changes need to happen - but it has to be a total culture change on the issue. In other words, I don't feel much will change if the same lack of training/education is being passed around. That just gets us ignorant pilots under larger canopies and not much else. Larger canopies will only make those with more jumps feel comfortable about what the 'kids' are doing, but it doesn't make them any less likely to screw themselves in.

I've seen some very small women (90-100 lbs) start AFP on a 135 and fly it smart and safe due to the extensive education they received. Meanwhile, I watched someone pound in under a 260 that had much less instruction.
_________________________________________
you can burn the land and boil the sea, but you can't take the sky from me....
I WILL fly again.....

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A few months back I watched a guy loading a 190 square (Sabre 2 maybe?) just a hair over 1 smoke past me under my 1.5 loaded 99. I think the forward speed is more likely gonna cause injuries than the fact that the smaller canopies turn faster.



You're saying the speed on a 1:1 190 is greater than a 1.5 99?

That just doesn't sound right.

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You're saying the speed on a 1:1 190 is greater than a 1.5 99?

That just doesn't sound right.



I read it the same way - seemed odd to me. I've jumped a ST190 at 1.5wl and it isn't fast, nor is it twitchy (it doesn't fly anything like a ST150 IMHO).
_________________________________________
you can burn the land and boil the sea, but you can't take the sky from me....
I WILL fly again.....

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You're saying the speed on a 1:1 190 is greater than a 1.5 99?

That just doesn't sound right.



I think it was about 1.1 but absolutely. He definitely was smoking me. I had a much greater descent rate - but forward speed absolutely. His was a 9-cell Sabre2 I believe, and mine was a 7-cell Triathalon, but you'd be surprised at how much faster the big canopies fly than the little ones..

I think most people think of little canopies as so fast because they're used to seeing average-sized males under the highest performing canopies (Velocities, Extremes etc). Throw a small 120 lb person under a Spectre and its night and day difference.

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Oh I understand that part of it, what Im curious about is if I could tomorrow just go out and downsize to a 170 since according to the chart it is still a safe size for my weight? I doubt it is, but Ive wondered this often
Sudsy Fist: i don't think i'd ever say this
Sudsy Fist: but you're looking damn sudsydoable in this

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