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Are manufacturer canopy sizing recommendations quite conservative?

 


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Aug 17, 2012, 2:34 AM
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Are manufacturer canopy sizing recommendations quite conservative? Can't Post

Do canopy manufacturers tend to publish quite conservative size/wingloading guidelines, would you say? Im around 90kg (200lbs), without any gear. I have about 30 jumps, all recently. My instructor and others at the DZ have talked about me looking for canopies around 190 or even 170. I was originally thinking of something over 200, like a 220 or so. The smallest Ive flown so far is a 230 (the next size down in their rental rigs is a 190, I believe).

Given how rare it is to find second-hand canopies over 200sqft (even 190s are uncommon), I could be waiting a long time to find anything a bit bigger. I have a decent offer on a Sabre 2 190 which Im tempted by, but my first thoughts were that I ought to take something a bit bigger. A chart Im looking at here suggests I stay on 210s and 230s until Ive got over 200 jumps or so, and PDs Sabre 2 sizing chart recommends a 190 for only "advanced" and "expert" jumpers of my weight range.

Are my instructors and others being reckless in saying that a 190 is ok? Or are the manufacturers being understandably conservative and cautious? I have no particular wish to get a small canopy at this stage I do want a *good* canopy, though, that will be fun and safe to fly. If I had this same Sabre 2 offered to me but in a 210 size, I would definitely get that instead of the 190. But I struggle to find kit of that size, as mentioned before, and realistically the choice is between a newer, smaller canopy and a much older, larger canopy, which perhaps would not perform as well or as safely on balance.

Thanks for any advice,


Jalien  (A License)

Aug 17, 2012, 4:14 AM
Post #2 of 21 (1531 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

I'm sure others with loads of experience will be along shortly to tell you why you should be conservative in your canopy sizing. But for my own interest, how many instructors at what level (e.g. CCI, DZO, whatever) suggested moving straight on to a 170? (I make that about 1.3 wing loading). What DZ is that (I think you jump in the UK, no)?

I would suggest trying their 190 before buying one, if they are happy with that, and never jumping something you aren't comfortable with for reasons of finances or peer pressure (or even due to "good advice")

good luck finding kit! Smile


Quagmirian  (A 110392)

Aug 17, 2012, 4:36 AM
Post #3 of 21 (1519 views)
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I would say this is the one time where you can say no to your instructors. If you feel uncomfortable on a smaller canopy, there's nothing wrong with going for something larger. Remember that people may be giving you maximum or average wing loadings for your experience level, and there will always be people who want something bigger over their heads. I'm not saying your instructors are wrong, not at all.


rss_v

Aug 17, 2012, 4:41 AM
Post #4 of 21 (1517 views)
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Re: [Jalien] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
I'm sure others with loads of experience will be along shortly to tell you why you should be conservative in your canopy sizing. But for my own interest, how many instructors at what level (e.g. CCI, DZO, whatever) suggested moving straight on to a 170? (I make that about 1.3 wing loading). What DZ is that (I think you jump in the UK, no)?

I would suggest trying their 190 before buying one, if they are happy with that, and never jumping something you aren't comfortable with for reasons of finances or peer pressure (or even due to "good advice")

good luck finding kit! Smile

To be fair, the "170 or even a 150" came from an instructor (AFF) who didn't have anything to do with me personally, and he may have been talking about further down the line, a bit later in my "career". Another who I am much more involved with has approved a 190 as suitable, but we didn't discuss it at length. I'll definitely jump the rental 190 before purchasing one, yea.


Premier skybytch  (D License)

Aug 17, 2012, 5:18 AM
Post #5 of 21 (1496 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
Are my instructors and others being reckless in saying that a 190 is ok?

What they are doing is showing you that the only person who cares whether you get hurt or not is you.

You now know what the manufacturer thinks, in addition to what your instructors think. The folks who wrote those charts just may have a bit more information about parachutes than your instructors do. It's likely they have more actual skydiving experience than your instructors do.

You decide who to listen to. You could get a 170 and be just fine; some people's skill bags fill up before their luck bags empty. You could get a 210 and somehow still manage to hurt yourself.

btw, a 15 or 20 year old original Sabre or Triathlon is just as good a first main as a brand new Sabre2... especially if you want to save some money.


guitar_nut  (A License)

Aug 17, 2012, 6:44 AM
Post #6 of 21 (1448 views)
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I'm the same weight and had about 60 jumps when I bought my rig. I've got about 12 jumps on my gear so far. I bought a 230 loaded at 1:1 and swapped out my rig's reserve for a larger one. Personally, I'm glad I went with a bigger main, even though I had to wait longer to find one. I have more time to think while in the pattern, my approach speed is slower, downwind landings are do-able, and it recovers very quickly from any sort of abrupt turn. I'm not planning on doing anything stupid, but if I do, I've got a little more room for error.


DocPop  (C License)

Aug 17, 2012, 8:00 AM
Post #7 of 21 (1414 views)
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In reply to:
Are manufacturer canopy sizing recommendations quite conservative?

Yes. As they should be.

Manufacturer's charts have to be applicable to all potential users of their product and therefore need to be conservative in order to keep all their customers safe.

By the time you find out that your canopy is too small for you - it's too late.


Premier billvon  (D 16479)
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Aug 17, 2012, 8:32 AM
Post #8 of 21 (1391 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

People thought they were sorta aggressive when they first came out because people on average were jumping larger canopies back then. Now everyone thinks they are very conservative because people are jumping smaller canopies on average.

However the laws of aerodynamics haven't changed. The same sized canopy will hurt you just as badly if you mess up to the same degree. More canopy coaching is available, which is a good thing, and can help you downsize faster. But it is a mistake to assume that since everyone seems to be downsizing faster nowadays, that there is some sort of safety surrounding the process that gets spread by osmosis.

If you are worried about the older canopies, then perhaps buying an old zero-P canopy and getting it relined is the answer. ZP fabric lasts several thousand jumps, and changing out the lines will restore it to almost-new performance. It will also be a lot easier to pack. And with the money you saved you can get some canopy coaching, and if you then want to downsize after 50 jumps or so you won't be out so much money.

Overall for you a 210 or 220 sounds like a good choice.


Skydivesg  (D 10938)

Aug 17, 2012, 8:39 AM
Post #9 of 21 (1387 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

Do your instructors have a vested interest in selling a smaller canopy? I've known instructors who are morons.

When I witness someone who makes a mistake while landing I often ask them if they wish they had a smaller canopy. You can imagine the responses but none have ever said yes.

Larger lower-wing-loaded canopies (in general) will always be more forgiving than smaller heavier loaded ones.

We all make mistakes while under canopy even those of us with thousands of jumps.

Until you have the experience to deal with those mistakes it's wise to have a parachute that is more forgiving of the mistakes. I can name at least 6 people in the last couple of years who no longer jump because they made mistakes while landing.

In all of these cases a larger - slower - more docile canopy would have given them the added margin of error so that they would likely have gotten up bruised, scraped and embarassed instead of the hospital trip that ended their skydiving.

It's your body. Do what you think is right.


mjosparky  (D 5476)

Aug 17, 2012, 11:39 AM
Post #10 of 21 (1339 views)
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Re: [Skydivesg] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
Do your instructors have a vested interest in selling a smaller canopy? I've known instructors who are morons.


If your instructors own the canopy or if it belongs to someone they know..walk away. They do not have your best interests in mind.

Sparky


rss_v

Aug 17, 2012, 12:38 PM
Post #11 of 21 (1316 views)
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Re: [mjosparky] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
Do your instructors have a vested interest in selling a smaller canopy? I've known instructors who are morons.

In reply to:
If your instructors own the canopy or if it belongs to someone they know..walk away. They do not have your best interests in mind.

Sparky

No, I must emphasise that this isn't the case. The gear I'm looking at is from sellers completely external to my DZ with no known connection to my instructors.

It's a good point to raise, though.


JackC1

Aug 17, 2012, 12:50 PM
Post #12 of 21 (1306 views)
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Unless you actually told them your weight when asking for canopy advice, maybe your instructors thought you look lighter than you actually are. People underestimate my weight all the time.


rss_v

Aug 17, 2012, 12:56 PM
Post #13 of 21 (1299 views)
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Re: [JackC1] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
Unless you actually told them your weight when asking for canopy advice, maybe your instructors thought you look lighter than you actually are. People underestimate my weight all the time.

Yea, I was thinking that. I'm 200-210lbs naked (there's a thought for you all...) at 6ft, but it's allllllll muscle, baby, so I probably don't look that heavy. I have definitely mentioned my weight to them before but it could easily have been forgotten. I will try to jump this weekend and grab someone to sit down with and talk to about it clearly.


crotalus01  (B 28932)

Aug 17, 2012, 10:48 PM
Post #14 of 21 (1226 views)
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My only advice is to not get a Sabre 190 or a Sabre 210 - they are notorious for opening HARD. My last jump on my Sabre 190 it opened so hard it broke 9 lines (including tearing off the bottom skin attachment point on a couple) and damaged a couple of cells.
I have my opinions on your wingloading as well, but I will leave that to the folks who know a lot more than I do Smile

ETA I believe both the 190 and the 210 have the double brake lines, and I think I recall a rigger telling me that contributed to the hard openings, but I could be way off - it was a few years ago.


(This post was edited by crotalus01 on Aug 17, 2012, 10:50 PM)


rss_v

Aug 18, 2012, 1:14 AM
Post #15 of 21 (1210 views)
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In reply to:
My only advice is to not get a Sabre 190 or a Sabre 210 - they are notorious for opening HARD. My last jump on my Sabre 190 it opened so hard it broke 9 lines (including tearing off the bottom skin attachment point on a couple) and damaged a couple of cells.
I have my opinions on your wingloading as well, but I will leave that to the folks who know a lot more than I do Smile

ETA I believe both the 190 and the 210 have the double brake lines, and I think I recall a rigger telling me that contributed to the hard openings, but I could be way off - it was a few years ago.

Really? All the reviews on this site talk about 1000ft snivels and super soft openings :/


adamUK  (C 104423)

Aug 18, 2012, 1:30 AM
Post #16 of 21 (1209 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

They do bite you occasionally. This seems to have been fixed with the sabre 2 apparently.

If you can jump some rental/demo gear then that would help. Which is your home DZ?


DrewEckhardt  (D 28461)

Aug 18, 2012, 12:46 PM
Post #17 of 21 (1169 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
Given how rare it is to find second-hand canopies over 200sqft (even 190s are uncommon), I could be waiting a long time to find anything a bit bigger. I have a decent offer on a Sabre 2 190 which Im tempted by, but my first thoughts were that I ought to take something a bit bigger. A chart Im looking at here suggests I stay on 210s and 230s until Ive got over 200 jumps or so, and PDs Sabre 2 sizing chart recommends a 190 for only "advanced" and "expert" jumpers of my weight range.

Are my instructors and others being reckless in saying that a 190 is ok?

Yes. A 230 is the best idea.

Most skydivers think we're special snowflakes all unique with our own strengths.

This leads to the canonical new skydiver advice to "listen to your instructors" "who've seen you fly" when it comes to down-sizing, the implication being that those instructors can some how recognize skydivers' specialness and approve of more aggressive downsizing protocols which is complete crap.

People should be sizing their canopies based on the worst possible situation:

It's the sunset load, cute chicks flash the pilot for extra altitude, some one in your group gets hypoxic and catches their foot on the seatbelt so you take forever to climb out, you have a long spot so you're landing off, and the low light means you don't see power lines until you've almost on top of them so you make a low turn to avoid them for a down-wind landing on an asphalt road.

not the sunny-day scenario of into the wind in a sunny wide-open field that's neither hard nor taxing and gives skydivers an incomplete picture of their abilities.

Instructors and a skydiver could only observe that they're ready for a premature down-size if they're getting into such situations on a regular basis and handling them successfully. Either that hasn't happened and there's no basis for the special snow flake recommendation, or the skydiver in question is short bus special in the judgement department and shouldn't be downsizing faster.

Other sides to this are operating at a sufficiently low mental arousal level, developing muscle memory, and learning situational awareness.

People perform best in situations that are stimulating enough that they're not falling asleep, but not unfolding so fast that they're overwhelmed where things like freezing become common. Premature down-sizing makes it easy to over-stimulate yourself and do incorrect things like hanging onto a front riser or two until impact. You need enough jumps in slower situations with bigger canopies to get used to it so that's less likely to happen.

Although you can almost yank controls as far as you'd care to with impunity under larger parachutes, canopies get more sensitive to control inputs as they get smaller, whether intended or not. People with too few jumps on intermediate sizes instinctively make the big movements which worked on large canopies but turn little ones into the ground at unsurvivable speeds.

Situational awareness means you've been doing things long enough to notice that things aren't right hundreds or thousands of feet before you're in a dangerous situation. People need to ease into things, with a hundred or few jumps on the next larger size and easing into larger turns making it easier to notice what's wrong so they're less likely to hang on controls until it's too late.

Following Brian Germain's 1.0 + .1/100 jump wing loading formula (with more complications) seems to work well on those counts and combined with practicing the skills enumerated by Brian and Bill von Novak radically reduces your chances of ending up in the incident reports.

Instead of telling skydivers to follow their instructors' advice which probably won't be based on enough information and allows people to ask around until they get an answer they like we should be telling them to follow Brian's writings unless complicating factors (bad depth perception, poor accuracy, not flaring far enough to avoid running, etc) noted by them or some one else suggest they be even more conservative.


(This post was edited by DrewEckhardt on Aug 18, 2012, 1:18 PM)


DrewEckhardt  (D 28461)

Aug 18, 2012, 1:18 PM
Post #18 of 21 (1155 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

In reply to:
In reply to:
My only advice is to not get a Sabre 190 or a Sabre 210 - they are notorious for opening HARD. My last jump on my Sabre 190 it opened so hard it broke 9 lines (including tearing off the bottom skin attachment point on a couple) and damaged a couple of cells.
I have my opinions on your wingloading as well, but I will leave that to the folks who know a lot more than I do Smile

ETA I believe both the 190 and the 210 have the double brake lines, and I think I recall a rigger telling me that contributed to the hard openings, but I could be way off - it was a few years ago.

Really? All the reviews on this site talk about 1000ft snivels and super soft openings :/

The Sabre and Sabre2 are both nine cell canopies made by Performance Designs.

Beyond the name and that they have nothing in common.

The Sabre is PD's first zero-P rectangular canopy. It does not snivel unless you've modified it using something like a pocket slider. Many of the complaints you hear come from newer jumpers used to the softer opening designs made later. Some are due to out-of-trim examples that no longer open as they should.

The Sabre 2 is tapered and follows a handful of other non-square ZP designs. It was designed to open slowly like skydivers expect modern canopies to.


(This post was edited by DrewEckhardt on Aug 18, 2012, 1:34 PM)


rss_v

Aug 21, 2012, 7:59 AM
Post #19 of 21 (1050 views)
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Re: [DrewEckhardt] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

Thanks for the replies, all. I've looked into it a bit further, and talked in person with some people at my DZ. An important point has come up which is that focussing on size can be misleading because different canopies - according to their shape, material, age, etc. - behave very differently and a larger canopy is never necessarily a slower/safer/easier one. One option I have is a Fury 220 that's 23 years old, with 500 jumps. It's been suggested that the 9-year-old Sabre 2 190 with 600 jumps would have a lot more flare in it and would generally be easier to control than the old, porous Fury.

What do you reckon to that general idea? It sure makes things trickier for an idiot like myself who knows nothing of different canopy characteristics.


5.samadhi

Aug 21, 2012, 9:05 AM
Post #20 of 21 (1027 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

f111 with that many jumps will suck a fat nut


DrewEckhardt  (D 28461)

Aug 21, 2012, 12:55 PM
Post #21 of 21 (985 views)
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Re: [rss_v] Are manufacturer canopy sizing recommendations quite conservative? [In reply to] Can't Post

 
In reply to:
Thanks for the replies, all. I've looked into it a bit further, and talked in person with some people at my DZ. An important point has come up which is that focussing on size can be misleading because different canopies - according to their shape, material, age, etc. - behave very differently and a larger canopy is never necessarily a slower/safer/easier one. One option I have is a Fury 220 that's 23 years old, with 500 jumps.

No. You'd be jumping that canopy with a wing loading beyond its design goals and the age means it may not be flaring well.

In reply to:
It's been suggested that the 9-year-old Sabre 2 190 with 600 jumps would have a lot more flare in it and would generally be easier to control than the old, porous Fury.

That still doesn't make it the best first canopy because the size and wing-loading make unintentional over-control close to the ground more likely.

Follow Brian Germain's advice. Follow Bill's advice. Learn to land down-wind and cross-wind, up-hill and down-hill, making flat and flare turns down to ground level, and with some added speed from front risers. Learn to land flaring from at least half brakes. That'll be easier and safer with more square footage.

If you still want to go faster and turn quicker after getting things like that dialed in and accumulating an appropriate number of jumps according to Brian's chart get another used canopy, sell the one you had for about what you paid - $1/jump (assuming you got a decent price), and repeat the process. Your first container (unless it has the closing loop mounted on a main flap and assuming it was built for the canopy size you start with) will probably be good for two canopy sizes smaller which gets you to 250-400 jumps. With a good purchase price it too can be sold for what you paid - $1/jump. The observant reader would note that they may spend $2/jump on depreciation regardless of how many rigs they own on the journey.

In reply to:
What do you reckon to that general idea? It sure makes things trickier for an idiot like myself who knows nothing of different canopy characteristics.

Get a ZP main loaded at 1.0 pounds/square foot. Learn some survival skills which are also fun and exciting. Do not down-size to a smaller canopy which you are afraid to turn low - plenty of fatalities involve "not hook turn type people" who did not learn that and found themselves in situations (unseen power lines, did not quite make it back because winds picked up, etc.) where they had to and did. Do not down-size to a smaller canopy that you're unwilling to land down-wind because that leads to imprudent low turns (which can lead to mid-air collisions when executed correctly when you break the pattern and impacts with the ground when not). Do not down-size to a smaller canopy when you have not mastered the flat and flare turns which keep you from being an unguided meat-missile in the landing area which poses a danger to yourself and others. If you want to go faster it's safer to add some riser input to a large canopy when you're current and landing in a sunny wide open field than to get that speed from a smaller canopy where you're stuck with it when landing off the airport under less than ideal conditions.

At 200-210 pounds naked you're probably 230-240 geared up. 230/230 = 1.0. 240/230 = 1.04 which is close enough. 240/210 = 1.14 which is more like a 100-150 jump canopy and 240/190 = 1.26 which is more like 250 jump canopy. That's close to Brian's minimums; his recommended sizes are larger.

http://www.bigairsportz.com/pdf/bas-sizingchart.pdf


(This post was edited by DrewEckhardt on Aug 21, 2012, 5:26 PM)



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