Velocity 170 sqf

[DKflyer 0]

Hi forum
I have a simple question :
Is there anything wrong in using a crossbraced canopy on lower wingloadings (under 1.3)?
The reason i am asking is, that I have never seen or heard about these type of canopies bigger than 130sqf. Why is that? (I dont consider the old excalibur)
For example if you normally jump a conventional 9cell, why not get a crossbraced canopy in the same size to get better performance without loosing the "forgivingness"
Am I missing something fundamental here?
Thanks in advance
DKflyer

[eames 0]

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...why not get a crossbraced canopy in the same size to get better performance...

I don't think you'd get better performance. I think the x-braced, tri-celled canopies need a higher wing-loading for their performance increases to be realized. This may be because they need the extra weight underneath them to help shape their airfoil. I think the higher wingloading also helps to maintain a higher airspeed to keep the internal air pressure higher. They're higher performance because they're more rigid, more efficient airfoils, but they need the additional weight to keep them that way-- to stress the internal structure and to keep the airspeed high. I could be way off though... maybe one of the canopy manufacturers lurking here could help?
Jason

[PhreeZone 20]

Well... at a 7-15% larger pack volume, you are looking at needing at least one size larger container to fit a larger canopy. Then with the advancement of canopies and effeciency you can get increased proformance with a smaller pack volume and more square footage.
Plus the benifits of Crossbracing don't really appear till a certian wing loading and unless you are loading a big canopy up a lot, you won't see any proformance gain and have to deal with the ground hungryness of the canopy, the generaly poor openings and the increased pack volume.
If once you start down the dark path, forever will it dominate your destiny, consume you it will....

[eames 0]

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...the generaly poor openings...

Poor openings? On that point I'll have to disagree. Xaos' open quite nicely. I can't speak for the other types though.
Jason

[PhreeZone 20]

Look around at an FX or Velocity opening. They seem to be ugly on all the video I've ever seen compaired to other canopies. Its all a matter of personal opinion too... some people LIKE the 300 foot Sabre openings and hate the 700 foot Spectre openings.
If once you start down the dark path, forever will it dominate your destiny, consume you it will....

[SkydiveMonkey 0]

I've seen video of a friend's FX 99 opening stangely and then the end cells touch each other. Looks weird.
Danger could be my middle name. But it's Paul.

[hookit 0]

I've heard the theory before that cross-braced canopies need to be loaded highly in order to fly well but I don't buy into that. Just because the extra efficiency of a cross-braced canopy allows it to be flown at a higher wing-loading than a non cross-braced doesn't necessarily mean that you only benefit from that efficiency if you fly the canopy at a high wing-loading.
Take a look at the benefits of a cross-braced canopy: The cross-bracing allows for a more rigid wing with a smoother topskin. My understanding is that this allows the canopy to generate more lift at a given airspeed than the same canopy without the cross-bracing would have. That effect should be consistent regardless of the wing-loading.
I believe the main drawback to having a 170 sq. ft. cross-braced canopy would be the increase in pack volume. Also I would guess that it would seem like a real boat as compared to a non cross-braced canopy of the same size because of it's extra efficiency allowing for more lift. It would probably fly more like a 190 or maybe even a 210?
As far as cross-braced canopies being more ground hungry than non-cross braced I think they have that stigma mainly because they tend to be flown at higher wingloadings and I think any canopy flown at a high enough wing-loading is going to be ground hungry.
I've had the opportunity on two occasions to fly a Samurai 105 for several jumps followed immediately by a Xaos 104 (wing loading about 1.8). Interestingly the Sam felt a little twitchier and more ground hungry to me whereas the Xaos felt a bit more solid and seemed to fly a little bigger (I'm guessing that was due to it being a more efficient wing?). I was also amazed at the low-end flare of the Xaos. As a side note, I bought the Xaos because I was getting better surfs on it and the openings were slower and more consistent than the Sam.
That's my $.02. It's just my opinion and I definitely could be wrong. I'm curious to hear feedback from some of the industry folks as well.
-Trey

[polarbear 1]

I think the cross-braced canopies out there now were all specifically designed to be flown at high wing loading and correspondingly fast speeds. They probably have a thinner airfoil section to reduce drag, but this means they need a higher speed to produce the necessary lift.
*Note...there seems to be an argument as to whether or not the VX uses a Stiletto airfoil; knowledgeable sources have come in on both sides.
Without having been able to fly a 170 sq. ft. Velocity, I would guess that such a canopy at low wing loading would feel very sluggish. I think it is true that the smoother airfoil that results from cross-bracing is more beneficial the faster the canopy flies; a slower canopy may not benefit as much. This is all just an informed guess.
Somebody else mentioned pack volume; a Velocity 170 would pack up like a tank.

[rhino 0]

I believe they do need to be loaded.. First off the air intakes are smaller than a normal canopy like a Triathlon.. They require airspeed for compression..
It's the whole closed off rounded nose thing.. I wouldn't feel very comfortable under a lightly loaded crossbraced canopy. Mines well get a hp elliptical 9 cell like a crossfire.. Or even a sabre2.. If you aren't loading the canopy that much anyways you probably won't notice the perks of crossbracing.. I am jumping a crossfire 109, it's bottom end is FANTASTIC.
Rhino
Blue Skies .....

[flyinryan 0]

The Icarus web site says you won't really get a preformance improvment from the cross barcing until you get to higher wingloadings. go to www.icaruscanopies.com and look at the article on the FX, lots of info on its development.
I don't know though, as I have never flown a cross braced canopy.

[Jimbo 0]

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I think the cross-braced canopies out there now were all specifically designed to be flown at high wing loading and correspondingly fast speeds.

What about the new Cobalt cross braced tandem canopy? Think about this: 2 jumpers @ 200lbs each + 50 lbs of gear under a 350 sqft canopy produces a wing loading of 1.28. I'm guessing there's nothing wrong with, and maybe something right, about flying a lightly loaded cross braced canopy.
-
Jim

[rhino 0]

That tandem canopy PROBABLY has a much more open nose than say a VX does.. That's comparing apples to oranges..
Blue Skies .....

[SkyMissy 0]

Because the cost close to $2000, and why shell out that kind of cash when you know the performance doesn't improve SIGNIFICANTLY. I guess some of them have cool names.
13,500' to the ground. We're dressed like clowns. The door's open. Hit it!

[eames 0]

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I've heard the theory before that cross-braced canopies need to be loaded highly in order to fly well

I don't think they necessarily need to be loaded heavily to fly "well", as in, to fly like a Stiletto, but they do need to be loaded heavily to exhibit the flying characteristics they were designed to improve upon.

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The cross-bracing allows for a more rigid wing with a smoother topskin

Does it? All by itself? Or does the structure need to be stressed more than conventional designs to produce this rigidity and smooth, efficient airfoil? Why would the manufacturers themselves say that these designs need to be more heavily loaded if it wasn't true? They would surely be making more money if they were selling more of their more expensive products....

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I believe the main drawback to having a 170 sq. ft. cross-braced canopy would be the increase in pack volume

One of the drawbacks of a 98 sq. ft. cross-braced canopy is the pack volume, but people still buy them.

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As far as cross-braced canopies being more ground hungry than non-cross braced I think they have that stigma

I'm sure that this is partly true, because the increase in wing-loading will increase the horizontal and vertical speed of the wing, but a lot of it also has to do with the trim of the canopy, and I think they're trimmed more steeply make steep dives more easily achievable.
cobaltdan, groundzero, anybody??
Jason

[polarbear 1]

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What about the new Cobalt cross braced tandem canopy? Think about this: 2 jumpers @ 200lbs each + 50 lbs of gear under a 350 sqft canopy produces a wing loading of 1.28. I'm guessing there's nothing wrong with, and maybe something right, about flying a lightly loaded cross braced canopy.

Good point, I forgot about that one (hey, it's new). One thing I should say is that there isn't necessarily anything WRONG with flying a lightly loaded cross-braced, it' just that the performance gains won't be there/the same. As stated earlier a canopy designed specifically for higher wingloadings might feel sluggish at lower wing loadings. This might be desired in a Tandem.
Whatever the case, I feel comfortable saying that a Tandem isn't intended for the same performance envelope as a swooping canopy...it's supposed to be at lighter loading and more docile. The original question applied to swooping X-braced canopies, meant to be flown at higher loadings.
Also, everyone I have heard from says that Cobalts also "fly big", meaning that they will feel sluggish at low wing loadings...I think the whole premise of the ultra-performance canopies is that you get the diving characteristics of small highly-loaded canopies coupled with better low-speed performance of larger canopies; you also don't get the twitchyness associated with some small highly-loaded canopies. Thus, you can fly a smaller canopy.

[rmsmith 1]

One issue with the highly elliptical canopies is the trim, specifically the angle of incidence. The trim on the highly elliptical canopies is flatter, which helps them glide easier whereas the trim on a rectangular seven-cell canopy is more aggressive, which help it stay inflated in turbulent conditions. Even the highly elliptical nine-cell canopies require higher wing loadings than the rectangular canopies. In order for the highly elliptical canopies to remain solidly inflated requires an increased wing loading.
The decision boils down to the type of landings you desire, i.e., tip-toe on a selected spot, or a swoop requiring a runway. The easiest choice is to have two canopies complete with separate risers, deployment bag, and pilot chute so that swapping them requires a minimum of effort. Even better yet is two complete rigs.

[polarbear 1]

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All by itself? Or does the structure need to be stressed more than conventional designs to produce this rigidity and smooth,
efficient airfoil? Why would the manufacturers themselves say that these designs need to be more heavily loaded if it wasn't true? They
would surely be making more money if they were selling more of their more expensive products....

Cross-bracing will make a canopy more rigid and smoother, even at lower wing-loadings (lower speeds). There is still a great amount of pressure in the canopy cells "pulling" against the bracing at lower speeds.
As far as designers saying they need to be heavily loaded, well, keep in mind that cross-bracing by itself doesn't necessarily do this. The combination of design parameters (planform, airfoil, trim, etc.) create a design that "likes" more loading. You could put cross-bracing in a Para-Foil and a have a canopy that does better with light loadings.

[eames 0]

It all boils down to money anyway. If large cross-braced canopies provided characteristics that more people wanted (demand), then the manufacturers would sell them (supply). We can speculate about why that isn't the case until we turn blue, but we're really arguing a moot point unless a manufacterer speaks up and explains it to us.... I've said my piece.
Jason

[cobaltdan 0]

will there be cross braced canopies in the future intended for low wing loadings: probably a few.
all of the points posted against are valid, but understand to build a braced canopy for low wing loadings you will not geometrically scale up existing models. design variables need to be reengineered for this specific purpose.
we are currently experimenting with a competition cobalt variant intended for low wing loadings. its leading edge airfoil is braced, but without lowering the drag on the nose significantly. it is intended for begineers - intermediates and will be available in sizes from 135-210
sincerely,
dan.

[polarbear 1]

You've got my attention!

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[rhino 0]

I am sure if you crossbraced a Diablo or a Triathlon you would have an emazing performance difference..
Any open nosed canopy COULD probably benefit from crossbracing.. Pack volume? Who cares how big it packs.. I don't weight pack volume in any decision I make concerning canopies..
I'd like to see a crossbraced Diablo? I wonder how much of a performance difference there would be? Even a Triathlon? Interesting concept..
Blue Skies .....

[GroundZero 0]

Jason,
Great comments!
Currently, market demand drives design. The Xaos-21 is a higher cost canopy due to the number of pieces that need to be connected. A Raven consists of 22 pieces of material. A Xaos-21 is 58 peices (don't hold me to that, I'm at home and not looking at the files.) Because of the complex construction, these canopies carry considerably higher manufacturing costs and retail/street pricing.
We have built larger crossbraced canopies. I like to use a Xaos-21 108 for demos. The canopy at lower wingloadings does nice "braked" accuracy approaches, (160 lbs. + 20 lbs gear = 1.66 lb/sq. ft.). We have experimented with wingloadings on x-braced canopies at ~1.0. There is a performance increase. The "scaled" version in the larger size on lighter wingloading has sufficient internal pressures. The problem is that there is virtually no demand for a canopy with a $2200.00 retail price for the jumper that has alternatives for $500-1000 less, that will deliver him(her) comfortably to the ground. Pack volume increase means that you can typically step down 2 sizes, get the same performance with similar pack volume. Simply, how many jumpers that are currently jumping a (insert yout favorite mid-performance larger canopy here) are willing to spend $500+ more to simply get a nice ride down.
Things may change in the near future. As I age, (43, sometimes feel like 63, but look like 33!), I DEMAND comfortalbe openings. While other x-braced openings may be "interesting", the newest generation of x-brace leads the industry in, (how do you spell it?), SCHWEEEEET! openings. I feel openings alone will drive x-brace into mainstream skydivers' containers.
(Jason, you gotta agree on these openings!)
I drive 150 miles every day to and from work. I drive a (very) high milage minivan to work and back. I love to drive (fast), that's why my weekend car is a Maserati. Different applications require different tools. That's why we and other manufacturers offer so many "buttons on our drink machine".
Don't be surprised if you see a cross-braced mid-performance canopy in the near future...
Chris

[GroundZero 0]

oh...
One more comment... Ground Hungry... NO
I do lots of AFF... last out, i.e. LONG... open quite often below 3000' and I always get back as far or further than my students who opened 1000'+ above me on a very lightly loaded student canopy... These x-braced canopies are not aimed at the ground.
Chris

[MrHixxx 0]

I'll have to concur on openings and glide with previous posts. My Xaos 98 opens better than anything I have jumped and I have always had good opening canopies (triathlons and a cobalt). Also with relatively easy rear riser pressure, the Xaos flatens out quite nicely and holds altitude well with the 2.19 wingloading I put under it...
-Jon
"Sous ma tub, Dr. Suess ma tub"

[hookit 0]

Wow...great feedback, everyone. Thanks especially to Dan and Chris. I really enjoy reading the feedback from the industry 'insiders'.
Blue Skies, Soft Landings and Long Safe Swoops!
-Trey