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NexGenSkydiver

Bottom End of Swoop

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I don't like some of the comments that have been made please don't judge me until you have seen me fly




Relax friend. If you read my post, you'll see that it's not directly addressing you or anything you personally do. It's simply a breakdown of the rear riser/slingshot situation, and what needs to be considered or accounted for.

In terms of your rear riser stall comments, the speed at which you enter, and the pitch of your canopy when you enter will effect the stall characteristics.

Angle of attack and pitch are two different things, but closely related. They both move along the same axis, but pitch angle is related to the ground, and angle of attack is related to the relatve wind. When in a dive, your pitch anlge is a high negative number becuase the canopy (in ptich axis) is waaay off of horizontal. Your angle of attack however is not far off your canopy's trimmed angle of attack with regards to the relative wind.

The way you recover from the dive is to pitch the canopy up, which you do by adding some sort of input. This gets you moving forward under the wing, and bringing the nose up.

This is actaully the basis for the slingshot theory, that being that if you use a little input to scoot yourself forward under the wing, you can come forward faster and thus loose less speed in the transition from diving to level flight.

Back to the stall situation, if you were to dig on risers, you're essentially over-doing the slingshot idea. Once you accelerate your movement under the canopy, you create momentum which can cause you to come too far forawrd, and cause the canopy to pitch up too far, increasing the angle of attack, which as we know leads to a stall.

To compound this is the G-loading you induce by pulling out of the dive. When you combine that with the increased airspeed (and airspeed of course increases the sensitivity of your controls), and the possibility for you to 'slingshot' yourself too far forward under the canopy, you do a have a situation where the stall characteristics will be different than you may be used to.

Additionally, the faster the canopy is flying, the faster everything happens, including the speed at which a stall will break. This is why I mentioned that this type of stall will be different than a rear riser stall at the end of a swoop. In that case the canopy is level, the pilot's position under the wing is fairly stagnent, and the airspeed is slow.

Many, many times I flown my rears to a stall at the end of a swoop and quickly switched to toggles before getting dropped on my ass. It's not a big deal because the stall is very tame, with a slow and even break, and it's a snap to manage. This is the scenario that most swoopers are used to when it comes to rear riser stalls, and I want to make sure you understand that is you find yourself in the corner on rears, the stall will be much different, and the consequences will be much higher.

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EVERY canopy that is out there these days recovers on its own. From a Navigator at .8, a Jedei at 1.7, Katana at 2.2 or a Velocity at 2.9 they all have a natural tendacy to recover from a dive.



The Parachute and its Pilot, p. 80:

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The higher the wing loading, the longer the dive will be, even within a singular model of canopies. For instance, a Samurai loaded at one pound per square foot will recover quickly, achieving level flight without any input from the pilot. On the other hand, a Samurai loaded at more than two pounds per square foot may not recover completely from the dive at all. It will continue to lose altitude until the pilot provides some positive angle of attack or gradually returns to its natural full flight glide ratio.



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The canopy doesn't dive forever, you probably just started, or better yet, ended your turn too low.



Perhaps you misread my post. I said "needs input in order to plane out". It would seem that some canopies do need this.

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Underloading- Is a word that should be stricken from peoples vocabulary. A Katana at 1.4 is not underloaded. A Velocity at 1.9 is not underloaded. The canopy will open fly and land just as it was designed. It just may not be as fast as YOU would like.



So a canopy wasn't designed to fly in a particular wingloading range? I'm not saying the canopy stops flying or anything, but does a Velocity 120 really fly the way it was designed to with a 95-pound girl under it?

Why does Icarus recommend the Crossfire be loaded at 1.4-2.1?

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Treating an "optimal" wingloading provided to you by one of your friends as gospel isn't going to help you out.



Why the condescension?

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There's a big difference by saying that a canopy recovers or that it levels out.
I've never jumped a canopy or gained so much speed with it (100mph isn't enough with my velo) that it levels out to level flight with no input at all.



It's a function of canopy design and wingloading.

My Stiletto 120 did at a wing loading of 1.6 - 1.7. Turn, release front riser, swoop, apply brakes, swoop more.

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It just isn't enough to let the canopy recover...you have to do a little bit more, to make it fly level.



Modern designs built for swooping don't. It's a lot more user friendly because you can finish a little high and descend to swoop altitude while you still have plenty of speed.

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Ficus,

First, while I have the utmost respect for Brian G, Scott M, etc, I want to point out that you cannot use the book as gospel. In fact, the book makes mention of a 2.1 loading being optimal and that's already proven false. Now, that doesn't mean that the book doesn't contain good info, it most definitely does, but what I'm trying to say is that ideas about canopy flight are still being formulated. No-one has it 100% just yet.

So, with that in mind:

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Perhaps you misread my post. I said "needs input in order to plane out". It would seem that some canopies do need this.



Put enough speed into the canopy and it will. That doesn't mean it's the most efficient way to land it though (letting it totally recover), as that's another discussion altogether.

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So a canopy wasn't designed to fly in a particular wingloading range? I'm not saying the canopy stops flying or anything, but does a Velocity 120 really fly the way it was designed to with a 95-pound girl under it?



Yes, although the 'benefits' won't be noticable since they really kick in at high loadings. It doesn't mean the wing isn't working as designed. You can go and buy a Ferrari and drive it at 10 mph - it probably won't be any fun, but you can't say the car isn't working as designed.

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Why does Icarus recommend the Crossfire be loaded at 1.4-2.1?



Ask them? It's possible the recommendation is simply there to steer people away from a choice they would be unhappy with. In your above example with the small person under a velo 120 - it would 'feel' massive compared to a ST120. It wouldn't be any fun to fly.

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Why the condescension?



I didn't read it as such. He's trying to help.

Blues,
Ian
Performance Designs Factory Team

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a Samurai loaded at one pound per square foot will recover quickly, achieving level flight without any input from the pilot. On the other hand, a Samurai loaded at more than two pounds per square foot may not recover completely from the dive at all.


yeah, i also disagree with that. Infinite dive? i doubt it. Any canopy will recover on its own to its own "normal" flight. Level flight? Not for long. You can only achieve level flight for a short period of time with a skydiving canopy, by default.

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Any canopy will recover on its own to its own "normal" flight.



That's just a function of how and why a canopy dives, recovers and flares. A function of drag and weight transfer (aka the pendulum effect) I agree that every modern canopy made recovers on its own, it just might not give you the best swoop to let the canopy fully recover on its own.
--"When I die, may I be surrounded by scattered chrome and burning gasoline."

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First, while I have the utmost respect for Brian G, Scott M, etc, I want to point out that you cannot use the book as gospel.



My only real intention in quoting from the book was to invoke someone with a little more credibility, since I (perhaps understandably) don't seem to have much.

I'm sure Brian G. would be the first to point out he doesn't have all the answers, and I don't see his book as infallible.

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Perhaps you misread my post. I said "needs input in order to plane out". It would seem that some canopies do need this.



Put enough speed into the canopy and it will. That doesn't mean it's the most efficient way to land it though (letting it totally recover), as that's another discussion altogether.



In theory, sure, enough airspeed will create enough lift to plane the wing out or even cause it to climb without input. But does that mean that any design at any loading will necessarily be able to create that much speed? If you haul around a 450 degree harness turn (or whatever it takes to maximize airspeed) on a Velocity, will it climb? I'm not being rhetorical here -- I am very much under the impression that it will not.

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So a canopy wasn't designed to fly in a particular wingloading range? I'm not saying the canopy stops flying or anything, but does a Velocity 120 really fly the way it was designed to with a 95-pound girl under it?



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Yes, although the 'benefits' won't be noticable since they really kick in at high loadings. It doesn't mean the wing isn't working as designed. You can go and buy a Ferrari and drive it at 10 mph - it probably won't be any fun, but you can't say the car isn't working as designed.



Al seemed to take exception with my statement that I was "underloading" a Katana at 1.4. To continue your Ferrari analogy, I was driving it around at 10mph. The Ferrari's engine is obviously going to be tuned to output power most efficiently at a certain gearing and RPM. If the car is boring when I drive it around at 10mph, of course there's nothing wrong with the car. It is not designed to be driven around at 10mph.

I tried a Crossfire at 1.35 and didn't care for it. It didn't dive enough for my tastes and it was less responsive in the harness than I liked. 400 jumps or so later, I tried one again at ~1.75 and bought 2 of them.

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In your above example with the small person under a velo 120 - it would 'feel' massive compared to a ST120. It wouldn't be any fun to fly.



This is all I really meant by "underloading". I read Al's reaction as him thinking that I was saying "I need to downsize so I can get a better flare!" or some other such nonsense.

Ficus

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There's certain minimum L/D required for canopy to naturally planeout after a dive. In the simplest model when L/D is assumed to be constant during the dive and maximum possible speed is achieved and the canopy is planing out at the same L/D, planeouts will become level at L/D = 2.63 and higher (attached pic is a simulation of a wingsuit dive, but applicable to any nonpowered gliding flight alike). Lighter loaded canopies have higher L/D compared to highly loaded (of the same design and trim) ones, due to lesser effect from body drag at slower speeds, and are more "prone" to level planeout.

If your canopy tends to fly up by itself on a natural planeout, perhaps, a little bit more aggressive trim will stop this and also extend the swoop? Just an idea - I don't know how common custom re-trimming or relining are.
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There's certain minimum L/D required for canopy to naturally planeout after a dive.



You again ;)

I guess we should discuss this at the DZ because I don't immediately see how L/D affects recovery arc length and are you talking about L/D of the canopy alone or including the jumper? I would think the main factor would be drag on canopy vs. drag on jumper, how far forward the center of lift is on the wing at high speeds and line length.

In any case, I returned the canopy in question and I'm demoing canopies with longer recovery arcs in hope of buying one before the end of the season. This weekend, it will be a Samurai 150.

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There's certain minimum L/D required for canopy to naturally planeout after a dive...


I believe, that pendulum effect has more impact on whether canopy will plane out without input (actually the system canopy-pilot will apply this input by itself due to pendulum effect) or not...

And pendulum effect is a matter of canopy planform/trim/lines lngth/WL and type of turn etc...

OnTopic:
I Use rears to "slightshot" on every jump... seems to work for me:)
Why drink and drive, if you can smoke and fly?

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In theory, sure, enough airspeed will create enough lift to plane the wing out or even cause it to climb without input. But does that mean that any design at any loading will necessarily be able to create that much speed? If you haul around a 450 degree harness turn (or whatever it takes to maximize airspeed) on a Velocity, will it climb? I'm not being rhetorical here -- I am very much under the impression that it will not.


4 years ago that probably would have been the overwelming majority. You actually can get a velocity to perform like this. Take a look at some footage from of Fastrax or PDFT.
Bring a canopy to its theoretical max speed and then push it "beyond" that speed at a timed moment, and it will react differently in its recovery. It's pretty difficult to write a book that catches all of this, as Ian said, it is constantly growing and we are learning new things. We're all still learning whats possible.


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I tried a Crossfire at 1.35 and didn't care for it. It didn't dive enough for my tastes and it was less responsive in the harness than I liked. 400 jumps or so later, I tried one again at ~1.75 and bought 2 of them.


This is a great example, and I agree with you 100%. The next comments aren't pointed at "you". I want to use your example to make a point to the group so we can all maybe adjust our thinking on how we discuss wingloading, "underloading" and "recomended" wingloadings.
I'lll bring back the example of the Katana. at a loading of 1.4. you may be bored, but another jumper may be completely content. At 1.4 it meets his needs, given his experience, skill level, home dz altitude, and desire and assumption of risk. Feeding information to that other jumper that that the KA is boring at 1.4 and will perform better doesn't do him any service.

Ficus,
I think we're on the same page, but many others out there are not. Many believe that so called"underloading" makes a canopy unstable, or portray negative flight, landing or opening characteristics. And many jumper out there are scared of underloading their canopy, so they feel they NEED a smaller one or they are in danger! This is the mentality that needs to be dispelled. maybe it's not yours, but it's a pretty popular one out there that we as a group need to take responsibility to end.
Well I'm off to the dz to learn, see you guys!
************
Watch out for planters.

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I personally think you can "underload" a canopy. I don't mean that from a negative flight or opening characteristic (unless you're at an extreme end), rather that you get the downsides of a more extreme canopy (eg, less predictable openings, behaviour in line twists etc) without getting the full upside benefits that the canopy can offer, and they can be more difficult / dangerous to learn high performance landings on, should you choose to do so.

Why have a crossfire2 @1.4 when you can have a Safire2 @ 1.4? Why use a rear-engined sports car for commuting around town at 30mph?
--
BASE #1182
Muff #3573
PFI #52; UK WSI #13

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Hey, new guy, NO, you do not ever touch your rears unless you are fully "out of the corner" and could otherwise land sarfely on your toggles. It is not untill you have fully mastered the science of the turn, no matter, what degree, that you should consider using your rears. If you have done your research, read back at least six years on these forums, and have done all you can on your toggles, should you touch your rears. Rear riser landings (or "assisted" landings should not be attempted or even contemplated until you have your "traditional" front riser dive totally dialed in.

Feel free to either use the search function in this forum or either PM me directly for better descriptions of what I am talking about.

PS: Neither of the two major "canopy control" gurus who now run courses have EVER beat me in competition.

Chuck

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PS: Neither of the two major "canopy control" gurus who now run courses have EVER beat me in competition.



I have even out performed one of them on non crossbraced mains loaded at only 1.7...

D
http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

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Just a reminder that being a good competitive pilot, and a good teacher, don't go hand in hand at all.

There are plenty of great pilots, who're shitty teachers. Likewise there are plenty of pilots who don't place anywhere near the top 10 who are great at getting the theory across.

Blues,
Ian
Performance Designs Factory Team

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but of course...and let me just tell you that that same pilot taught me something a year after that competition.

So there ian...

:P:P:P

Dave

http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

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I only use my rears if I need to, I know where the stall point is with my rears. I have many canopy learning jumps, like pulling high and learning about my canopy and getting comfortable under it. I use the natural recover arch 95% of the time as that is what my canopy coaches have taught me, but I was wondering if there was any benefit from it, because one swooper who competed in the cpc told me that he puts himsel in the corner where he has to use his rears because it slingshots him out of the corner. I only have used my rears to correct my turn very little, but once I have gone threw the gates I have been playing with using them to carve or to trim the canopy to climb some.



If this is in reference to what I said the other day thats not exactly what I said. Could be something some one else said but sounds alot like my comment.
What I said was that I do put my self in the corner some(very little but my flame suit is on) but I never said where I have to use my rears. If your low dont ever use them.
I use my rears to plain out and my sameri 105 loaded 2.1 does kinda slingshot me out and I get alot more distance. But my sameri was tweaked by Brian to go faster. He also did some kind of tail mod because it did not do that prior.

And for the record I don't recommend anyone do anything I say or I do. And deffinately don't fly your canopy like me. It took me years to learn to fall down like I do. lol

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one swooper who competed in the cpc told me that he puts himself in the corner where he has to use his rears because it slingshots him out of the corner.



Shane... Wow, I haven’t been on the forums in about a month, and this is exactly what I don’t miss about them. :|I’m fairly certain you’re referring to things that I’ve said. However, you’ve taken 10 different thoughts or statements I've made in passing about my swoops at different times, took the bits you thought you retained, and pieced them into 1 very incorrect statement about my strategy and swooping in general. So let me try and clear some stuff up for you:

Consider the following scenario: PD Sponsored, Pro Swooping Tour Pilots that bail to toggles to dig out of the corner, pass through the gates with *massive* power, transition BACK to REAR RISERS, then back to toggles to finish off the flare. I could tell you that I’ve seen that *EXACT* scenario in competition at least 4 times… Each time I’ve seen it, the result are great competition runs (albeit often earning the pilot a yellow card).:o However, I can tell you that the pilot(s) would NEVER condone or endorse that course of action. (To make matters a bit grimmer, there’s at least 1 fatality (within the last year) that can be attributed to the pilot attempting to do just that.

I would never make a statement that condones using rear risers to get yourself out of the corner to get a better swoop, and I do not ever ”plan on using rear risers on every jump” to get the "slingshot effect." On the contrary, I’m slightly paranoid of high speed rear riser stalls. LOL. In fact, my UNDER application of rear risers during competition has been pointed out to me by various canopy pilots/coaches (Scott Roberts & Ian Drennan @ the Farm last year in reference to shortening up my recovery arc, & Jay Mo @ Lake Wales this year in reference to maximizing my distance runs by going deeper into rear risers before transitioning to toggles). I use rear risers to shorten my recovery arc *IF* I've set up properly, AND *IF* it will maximize my wing's efficiency throughout the entire swoop, and even then, I tend to transition to toggles sooner rather than later.

When looking at DISTANCE covered over a swoop course, that distance can be maximized by using a control input (ideally rear risers bec of lowest drag) to shorten that recovery arc (not ARCH) slightly. That is a VERY important point... rear risers are NOT being used to "pull out of the recovery Arc" as you’ve said this swooper Check out Brian Germain's book "The Canopy and its Pilot" if you're having a hard time visualizing what I mean. There are at least 2 copies at the DZ and the book has a ton of useful information. B|

Furthermore, that "slingshot effect", whether real or *perceived*, is not the result of mere rear riser application. It is largely dependent on your position relative to entry gates, your position in your recovery arc when the recovery input is applied, the amount of the input, and even wind conditions. The percentage of jumps where the “slingshot effect” is perceived is quite low (at least for me), as it requires a near-perfect initiation, propagation, and termination of the set up, speed building maneuver, recovery arc, and rear riser application. If you have to use excessive rear risers to shorten that recovery arc, you start introducing excessive drag, which is definitely counterproductive to a distance or speed run through a swoop course. As Ian said, the point is to shorten the recovery arc slightly by "forcing" the canopy to reach level flight. It's all a balancing act... because too much of this input, and at the very best you'll introduce unnecessary drag; at worst, the ground will break you. B|

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I was saying I use them if I have a bad setup, butte uses them every jump.....I did bot understand his belief behind it,



Again, thinking that rear risers should only be used in response to a bad set up will be hazardous to your long term health. I do use rear risers on 99 percent of my landings... but that's the tail end of a precise set up and only if I haven't put myself in a corner where I need to bail to toggles. As you know, I recently downsized to a Velo 84 after almost 1500 jumps on a Velo 90. Out of the 20 jumps I've put on it thus far, I've missed the gates twice, both times bec of traffic immediately in front of entry gates. However this has nothing to do with the “slingshot effect” you’ve heard about. Most of my swoops come at the end of working jumps, and they’re not done to maximize distance, hence you won’t see me pop-up using rear risers to maximize my distance. My goal at the end of these landings is simple: nice, smooth set up, pass through the 5’ gates, and maximize my distance over the ground (where I’m passing only a foot or less over the ground. That’s where I get my personal rush, being RIGHT over the ground. I apply an entirely different technique and (through and beyond the gates) when training for competition or on hop-n-pops.

There's a very important point that's often missed by those learning to swoop...And that is that ANYONE can swoop, but a great swoop [in competition or competition simulation] is only the end result of a good set-up. So it doesn't matter if you're doing 270's, 450's, or 630's... if you're 1 inch too high on the gates, the result is a 0. You could have massive power as a result of a great set-up, but if you cannot control or place that power through the gates, you may as well do a straight in approach; it’ll be safer and your scores (whether in competition or just personal satisfaction) will be higher at the end of the day.

There are sooooo MANY misconceptions in this sport, sometimes a result of taking ideas or concepts out of context. Many of them can be resolved by just asking for a clarification, or taking things and putting them into their correct context. I’m glad you posted this, because it definitely reinforces the need for SIT-DOWN, formal canopy coaching, training, and courses (the science behind canopy flight and the swoop) in addition to competent canopy coaching on actual jumps. To that end, we’re going to be doing some canopy workshops at the DZ within the next couple of weeks, with the goal of clearing some of the misconceptions and bad information out there about basic canopy flight and “swooping”. Hopefully you’ll be there to give your input and ask some of these questions. :)
Cheers!

--Jairo
Low Profile, snag free helmet mount for your Sony X3000 action cam!

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Cool, sounds good! B| I also sent Kaz the link to this thread so that she has the whole picture of what you're needing an explanation of.

See you this weekend... We'll definitely be drinking the liquor I owe Art for my Tandem cut-away/reserve ride.:|:o:)
Cheers!

--Jairo

Low Profile, snag free helmet mount for your Sony X3000 action cam!

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I have tryid different Crossfire, wingloaded from 1.3 till 1.6, and I think its perform much better on higher windload.
It was no problem to fly it on 1.3, but it respons better (not only quicker, but better), I find it easyer to flare perfect on straight forward fly (with no front risers). So imho, its for a reason why Icarus recommend to load it at 1.4-2.1.

And since you brought ferrari in hear. Take a testarosa, and drive in small roads with lot of turns, in around 150km/h. I promise you, you will love it!

And now go to nearest small town, with small roads as well, and drive there, try to "side park" between 2 cars, turn around maybe... You know what you find out? Its a lot better with a ford focus for that!

Velo dont made to be loaded at 1.3, it will fly, but a sabre loaded at 1.3 will do it lot better. Don you agree?
Blue skys and soft landings to all!

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Velocity is a more efficient wing than a Sabre. It still would fly better at that load too.



Disagree..

The main advantage of velo is the capability to maintain the wing efficient with high wingloads....with low wingloads, it might be a little bit more efficient but nothing more. And....openings are a lot worse (velo at 1,3.......how long is it going to take to get the slider down:ph34r:....and how many turns the canopy has time to do during that...) and harder to handle, it costs more, packs bigger etc...

I see no reason to jump a velocity at anything less than ~1,8

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