Big guys and BASE canopies.

[grue 1]

Since I'm nowhere near the experience level to take a BASE FJC or anything of that sort, I find that doing as much research as possible helps me pass the time, and hopefully I'll be well-educated when I get to actually start in the sport.

It seems that a .6 to a .75 wingload is considered the de facto norm in BASE, and I'm somewhat curious about what happens when you're a big guy. I'm 6'3" and about 225lbs, so assuming 15lbs or so for the rig (not even including body armour, etc), I'm looking at a 400 square foot canopy to get a .6 wingload.

Insofar as I've been able to find, the biggest BASE canopies are in the neighbourhood of 330sqft, and that's towards the high end of the recommended wingload, which is probably inadvisable for a newbie jumper.

Surely I'm not the first person to run into this issue, so what's typically done in this sort of situation?

cavete terrae.

[piisfish 135]

-jump naked
-loose weight
-cut a limb


question to experienced people ... Would a 330 loaded at .75 perform more docile than a 210 at the same wingloading ?? My logic would be yes, as with skyding canopies, the smaller, the twitchier (at same wingloading)...

Question for Grue : what size canopy did you have for your 1st jump ??

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[grue 1]

Haha, I don't have that much weight to lose, actually. I -might- be able to get down to 220 :P

In any case, my canopy progression:

Jumps 1-5: Skymaster 290 (Static line)
Jumps 6-10: Skymaster 230 (Ripcord)
Jumps 11-44: Raven IV (Throwout from this point on)
Jumps 45-current: Fusion 210

cavete terrae.

[JaapSuter 0]

Uhm....

245 / 330 = 0.74 < 0.75

So you'd be okay with a 330. There is actually another canopy-sizing rule besides the 0.6 to 0.75 rule that says; take your naked body weight in pounds and add 100.

Some say this rule more accurately describes the ideal wingloading since heavier people can actually benefit from slightly higher wingloading; e.g. the 0.6 to 0.75 rule is actually non-linear.

Jumping with a canopy this big does bring some considerations that not everybody is aware of though. When the time is right, I would recommend getting in touch with other people jumping canopies in that range and asking their advice.

Also, note that higher wingloaded BASE canopies can be great for some areas (terminal jumps with easier landings) and poor for other areas (low jumps with sketchy small landing areas that require deep approaches). Adjust your jumping to your abilities.

[grue 1]

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Uhm....

245 / 330 = 0.74 < 0.75

So you'd be okay with a 330. There is actually another canopy-sizing rule besides the 0.6 to 0.75 rule that says; take your naked body weight in pounds and add 100.

Ok, I guess what I read confused me a little. I thought the .6-.75 rule was for BASE in general, not just newbies. So in other words, I thought ".6 is for newbies, .75 is for very experienced jumpers"

Thanks for your help!

cavete terrae.

[TomAiello 25]

Typically, folks just buy the largest size canopy they can find. Be aware that the size numbers given by manufacturers aren't really that comparable between brands (for example, I once laid a Troll 290 on top of a Blackjack 310 and found them to be almost identical in size). So, don't be fooled into thinking you need to buy the canopy with the largest "size number." Decide which canopy you want (and demo several different canopies when making this decision), then order it in the largest available size.

Jumping skydiving canopies (which are available in larger sizes) isn't really recommended. Some people have tried to use military canopies, tandem canopies, etc, because they were available in such large sizes. Virtually every one of those I've ever seen has had some very strange (and undesirable) slider down openings.

You might also seek some input from other people in the same boat (i.e. folks whose body weight is high enough that they are "overloading" even the largest size canopies by traditional measures). There are a couple on this forum (if you need help finding them, drop me a PM).

Also, be aware that there are going to be jumps that you just aren't going to want to do, as a result of the wingloading and canopy size issues. Tiny people can land in bad areas, especially broken ground, much better than large people. This is just one of those things that you are going to have to accept, and shape your jumping style around.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[TomAiello 25]

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So in other words, I thought ".6 is for newbies, .75 is for very experienced jumpers"

Ouch. Nope, that's not the way it works.

In fact, in BASE, very experienced jumpers tend to jump lower wingloadings, usually because they've seen enough bad stuff go down that they want the extra safety margin (sometimes also because they are trying to land in more questionable areas, or for other reasons having to do with attempting more advanced jumps).

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[grue 1]

Quote

Quote

So in other words, I thought ".6 is for newbies, .75 is for very experienced jumpers"

Ouch. Nope, that's not the way it works.

In fact, in BASE, very experienced jumpers tend to jump higher wingloadings, usually because they've seen enough bad stuff go down that they want the extra safety margin (sometimes also because they are trying to land in more questionable areas, or for other reasons having to do with attempting more advanced jumps).

Ok, that makes good sense. I was avoiding studying when I was reading all this stuff the other night, so it was late at night and I was tired

Are BASE rigs in the same boat as skydiving rigs, in that the container's sized for a small range of sizes? Or does the nature of the way a BASE canopy is packed allow for more container size variation?

cavete terrae.

[JaapSuter 0]

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very experienced jumpers

Should probably say: "very few experienced jumpers"?

Please self-destruct this post after reading.

[dploi 0]

The very simple method I've seen for the proper BASE canopy size goes like so:

Weight of your naked body + 100. At 225, you'll want a 330.

[Calvin19 0]

aye... my first base gear was .79/1, and my new rig is .55/1.
That little dagger was crazy fast. is crazy fast. still jump it in moab...

[TomAiello 25]

Quote

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very experienced jumpers

Should probably say: "very few experienced jumpers"?

Please self-destruct this post after reading.

Good catch. Thanks. I fixed it.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[TomAiello 25]

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Are BASE rigs in the same boat as skydiving rigs, in that the container's sized for a small range of sizes?

Yes. It varies depending on the specific container, but many BASE rigs can accept a size up or down.

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Or does the nature of the way a BASE canopy is packed allow for more container size variation?

It usually allows for less variation than a skydiving rig.


Be aware that it's much safer to vary sizes with a velcro rig than a pin rig. In general, it's a good idea to jump a pin rig sized specifically for your canopy. Velcro rigs allow you a bit more wiggle room while still maintaining some safety margin.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[JohnnyUtah 0]

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So in other words, I thought ".6 is for newbies, .75 is for very experienced jumpers"

Ouch. Nope, that's not the way it works.

In fact, in BASE, very experienced jumpers tend to jump higher wing-loadings, usually because they've seen enough bad stuff go down that they want the extra safety margin (sometimes also because they are trying to land in more questionable areas, or for other reasons having to do with attempting more advanced jumps).

I disagree.
I have noticed the opposite to be true. Through the years I have seen many experienced BASE jumpers (including myself) start jumping a lower wing loading (usually a one size bigger canopy). The lower wing loading does give you less penetration but having a larger canopy over your head is a lot more forgiving while doing steep accuracy approaches and dealing with turbulent air.

Higher wing loadings are definitely the trend in the Skydiving environment for swooping and jumping in higher winds.

Have Fun, Don't Die!
Johnny Utah
My Website
email:[email protected]

[JaapSuter 0]

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I have noticed the opposite to be true. Through the years I have seen many experienced BASE jumpers (including myself) start jumping a lower wing loading (usually a one size bigger canopy).

That's what he meant, he has since edited the post.

Thanks for the clarification Johnny. I'll actually admit that I've always found the term wingloading confusing. I prefer to speak in terms of bigger canopy and smaller canopy since it appeals instantly to intuition; big is slow, small is fast.

Quick, anybody, answer this question in a millisecond without thinking; how do you calculate wingloading, weight over area or area over weight?

Did you cheat?

Obviously at some point the weight to area ratio is a useful metric, but in general discussions I like big and small.

And in life in general I like big; really big. But that's another story...

[JohnnyUtah 0]

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So in other words, I thought ".6 is for newbies, .75 is for very experienced jumpers"

Ouch. Nope, that's not the way it works.

In fact, in BASE, very experienced jumpers tend to jump higher wingloadings, usually because they've seen enough bad stuff go down that they want the extra safety margin (sometimes also because they are trying to land in more questionable areas, or for other reasons having to do with attempting more advanced jumps).

Ok, that makes good sense. I was avoiding studying when I was reading all this stuff the other night, so it was late at night and I was tired

Are BASE rigs in the same boat as skydiving rigs, in that the container's sized for a small range of sizes? Or does the nature of the way a BASE canopy is packed allow for more container size variation?

In skydiving people tend to downsize their canopy to a higher wing-loading as they gain experience, so I understand your thought process completely and you are sort of correct, whereby a more experienced BASE pilot should be able to handle the higher wing loading VS a new BASE jumper. BASE is not like skydiving in this way though, because experienced jumper still want the lower wing loading knowing the reality of the demands a BASE environment puts on the jumper.

Have Fun, Don't Die!
Johnny Utah
My Website
email:[email protected]

[Faber 0]

I think its more like a ballance thing..
Yes i want a big forgiven canopy over my head,but i like the fact that smaller canopyes crack open faster..

Stay safe
Stefan Faber

[wwarped 0]

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Quick, anybody, answer this question in a millisecond without thinking; how do you calculate wingloading, weight over area or area over weight?

wingloading = load placed on the wing

it becomes challenging as we just throw out numbers and ignore dimensions.

wingloading is simply a pressure, i.e. how much weight must each square foot support.

correctly stated, it's 0.75 lbs/sq ft.
(giving dimensions also permits people to convert to kg/sq meter.)

hope that helps!

DON'T PANIC
The lies in learning how to throw yourself at the ground and miss.
sloppy habits -> sloppy jumps -> injury or worse

[JohnnyUtah 0]

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I think its more like a ballance thing..

I totally agree with you Faber, it is about finding a good balance.
A canopy that is too big can have negatives traits about it. Bigger canopies pressurize slower on opening like you said (even to the extent of end cell closure problems), and they turn slower, and have less penetration.
So you want to try and get the best of both worlds.

Have Fun, Don't Die!
Johnny Utah
My Website
email:[email protected]

[sabre210 0]

I think i fall into the category of the larger jumper. I currently weigh 225lbs without gear. I jump the following configurations

ace280 for slider up jumps with larger landing areas which allow faster (skydiving type) toggles up, let it fly then flare approaches.

ace310 which i use for the whole range of jumps but not for jumps where i expect less than 5 seconds of canopy time, as i do experience more end cell closure and wierd pressurisation and jelly fishing.

troll305 which so far has been going great and i'd be happier to jump the lower stuff where i think canopy time is going to be under 5 seconds. The vents and valves mean it bangs open and pressurises solidly a lot more quickly than the ace.

As a bigger guy under a bigger canopy i currently avoid freefalls under 210ft. I just seem to get a lot less canopy time than my jump buddies, although there are too many variables involved to say with any certainty that it is down to the canopy size alone.

It is important to know your own limits. Not just ability but psychological limits and maybe even physiological limits. Just because you're a bigger guy doesn't mean you have stronger bones. Extra body mass puts more stress on your bones in an impact situation which lighter jumpers may just walk away from. Just because all these weedy little freaks can land in an area and be okay doesn't mean it will be okay for you.

Buy a good pair of boots (hanwags or the like). Your ankles will be pushed to their limits when 220+ pounds of man and rig comes banging down on them at 15mph. Your tib and fibs are seriously at risk. I've broken both mine left and right.

Seriously think about perfecting a good plf. It's better to be laughed at for plf'ing than to be laughed at for being on crutches.

Be prepared to have the piss taken out of you constantly, and don't be surprised if you land yourself a less than flattering nickname.

My one personal recommendation to a larger BASE jumper would be to try and build up a lot more upper body strength (which i lack in spades). It could prove very useful for climbing over fences, builders hoardings, suicide nets and barriers,hoists, trees, ladders, ropes and cliffs. You'll be wearing big sturdy boots which make it really difficult to climb in so you need to rely on your upper body strength (or the shoulders of a friend) and it means you'll be able to punch them harder when they start taking the piss out of you.

Your weight isn't necessarily helping you, but it certainly shouldn't stop you when the time comes for you to decide whether you want to get into BASE or not.


ian

[JaapSuter 0]

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"Quick, anybody, answer this question in a millisecond without thinking; how do you calculate wingloading, weight over area or area over weight?"

wingloading = load placed on the wing

it becomes challenging as we just throw out numbers and ignore dimensions.

wingloading is simply a pressure, i.e. how much weight must each square foot support.

correctly stated, it's 0.75 lbs/sq ft.
(giving dimensions also permits people to convert to kg/sq meter.)

hope that helps!

Sort of, but I bet it took you longer than a millisecond to type that answer. I'm well familiar with wingloading and what they mean. I was trying to convey that wingloading always takes a fraction of a second longer to understand than big and small does.

[wwarped 0]

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I bet it took you longer than a millisecond to type that answer. I'm well familiar with wingloading and what they mean. I was trying to convey that wingloading always takes a fraction of a second longer to understand than big and small does.

dude, I'm a blonde. my brain doesn't work at millisecond speed at ANYTHING.

"big" and "small" might be useful shorthand, but make comparisons difficult. how can you use these adjectives and provide guidance?

if you want to be totally geeky, realize your wingloading is the same as the average pressure differential between the upper and lower skins.

a canopy loaded at 2.25 must generate 3 times as much aerodynamic forces as one loaded at 0.75.

and actually, I was surprised by your original question. I didn't think my reply would contain anything new to you.

DON'T PANIC
The lies in learning how to throw yourself at the ground and miss.
sloppy habits -> sloppy jumps -> injury or worse

[diveout 0]

I'll chime in as I'm 220 without gear.

I also jump a Troll (MDV DW)305 now -I love it. I have a Mojo 280 that I've used on mostly slider-up jumps with clear, open landing areas -also frequently landing into a moderate headwind. I wouldn't want to land it on pavement or rocks.

I can easily see getting a 320+ in the future for more technical jumps and tight or knarly landing areas. Bigger is definitely better canopy-wise, but not in terms of pounds. I really like and emphasize the previous advice: 1) think hard about the types of jumps you plan (or DON'T plan) to do. 2) Use good boots 3) PLF's are OK

[Faber 0]

good post mate

Stay safe
Stefan Faber

[JaapSuter 0]

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"big" and "small" might be useful shorthand, but make comparisons difficult. how can you use these adjectives and provide guidance?

I totally agree. I was mostly referring to Tom's original post where there was initial syntactial confusion about whether experienced BASE jumpers fly canopies with a lower or higher wingloading. I find it much more intuitive if I read: "experienced BASE jumpers will tend to choose larger canopies."

Two cents...