Stitched risers?

[NoShitThereIWas 0]

OK so I am looking for some feedback from canopy swoopers and riggers on what their opinions are of stitched risers and how they affect the performance of the canopy. Any physics savy people who can explain the physics of why canopy pilots are stitching their risers laterally besides reduction in drag?

Thanks and blue skies.

Roy Bacon: "Elvises, light your fires."

Sting: "Be yourself no matter what they say."

[thepollster 0]

There is no reason except percieved reduction of drag.

[skydiverek 63]

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OK so I am looking for some feedback from canopy swoopers and riggers on what their opinions are of stitched risers

What do you mean by this?

[JohnRich 4]

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why canopy pilots are stitching their risers laterally

Do you mean the risers are oriented edge-on to the wind?

How does that interface with the 3-ring attachment point?

Wouldn't the line spread at the top, going up to the canopy, twist the riser back into normal orientation?

I'd love to see a picture of how that set-up works, to satisfy my curiousity.

[davelepka 4]

It's a standard riser, thats been folded over, and sewn down. The fold ends just above the riser insert. and just below the link.

[FrogNog 1]

How many square inches of frontal drag area does this reduce?

And, are the swoopers jumping these risers already wearing downhill ski suits? Or are they wearing shorts and t-shirts, and they don't even bother to shave their arms and legs?

-=-=-=-=-
Pull.

[dragon2 2]

Do you mean it's folded over to create riser blocks? Instead of diving loops?

I've got a pair of risers that's folded over to make them shorter so I can reach the slider, but swoopers usually want LONGER risers, right?

ciel bleu,
Saskia

[davelepka 4]

No, it's folded lengthwise, to make it skinnier for less drag.

It ends up looking like a soft cable housing, if you've ever seen one of those.

[dragon2 2]

Oh right, now I get it. Haven't seen that one yet...

ciel bleu,
Saskia

[justinb138 0]

It seems like stitching the risers like that is the skydiving equivalent of those big-ass exhaust pipes I always see on Hondas.

[Brains 2]

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It seems like stitching the risers like that is the skydiving equivalent of those big-ass exhaust pipes I always see on Hondas.

Probably, if you see a swooper with an "R" sticker on their helmet too, watch out.

In all seriousness, i have to think that this can only help the very top swoopers in the world where they have already perfected their form, and reduced drag everywhere else.

Never look down on someone, unless they are going down on you.

[davelepka 4]

I'm sure it's a small gain, but if you already have the RDS, and your choice of ultra thin lines, you might as well keep the trend going.

I've only seen pro swoopers use this so far, so it hasn't quite reached the same level as the coffee can exhaust on a Honda.

[darkwing 5]

As far as I am aware it is merely to reduce drag by cutting down the frontal area of the riser and making it more streamlined. It was suggested by Bill Booth quite a while ago, although I don't know if he originated the notion. As said above, it would seem to me that people often do a thing which will make a difference, while ignoring other things that will make as much or more difference.

-- Jeff
My Skydiving History

[riggerrob 643]

Compared with the drag/turbulence created by the human body, riser-created drag is insignificant.

[NoShitThereIWas 0]

Sorry it has taken me so long to reply. Basically, we are stitching the risers so that the leading edge is the thinnest part. What I meant by lateral was to give you some picture in your mind. When something is dorsally compressed think of the dorsal fin of a fish and where it is located. On the back of the fish. If you smooshed the fish dorsally you would compress it from its dorsal side like a sand dollar. Laterally compressed means compressing from side to side like a sunfish.

I am contemplating buying some risers from one of my ProSwoop buddies. We were discussing the stitched riser effect and there was no arguing that it reduces drag ...

but I have also heard that it makes the canopy more ground hungry and aggressive and I was wondering from those who have flown or know about stitched risers what their opinion is or how stitching the risers changes riser pressure thereby making it more aggressive?

Thanks and I hope that clears up some confusion

Roy Bacon: "Elvises, light your fires."

Sting: "Be yourself no matter what they say."

[davelepka 4]

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but I have also heard that it makes the canopy more ground hungry and aggressive

I cannot see how stiching a riser down will do anything but make it thinner. It should have no effect on the canopy flight at all (aside from the reduction in drag, which is minor).

I'd be more concerned about chnages to the functionality of the riser. Does it's usefulness decrease in any way? How about its longevity.

In reality, if you could beneift from the reductioni n drag, you're the sort of jumper who would want an increase to the dive-e-ness of your canopy.

If there does prove to be an increase in dive, let me know. Also let me know what kind of thread to use, becasue I'll stich mine down right away.

[Miami 0]

When I've jumped stitched risers the only big difference I noticed was that it was significantly more difficult to get a good grip on the rears for landing. Otherwise nothing really different.
Hope this helps...

Miami

[mjosparky 4]

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(aside from the reduction in drag, which is minor).

Dave,

I am sure there is some reduction in drag due the reduction in the frontal area of the riser. But I doubt that there are many swoopers that have access to the equipment needed to measure the difference. Some mods function like a rabbits foot.

Sparky

My idea of a fair fight is clubbing baby seals

[NoShitThereIWas 0]

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but I have also heard that it makes the canopy more ground hungry and aggressive

In reality, if you could beneift from the reductioni n drag, you're the sort of jumper who would want an increase to the dive-e-ness of your canopy.

If there does prove to be an increase in dive, let me know. Also let me know what kind of thread to use, becasue I'll stich mine down right away.

Well, steepness at this point would not bother me. I am under a lightly wingloaded Stiletto. A more aggressive dive at the ground will probably give me a better flare.

I will let you know about the dive increase if I get one. I have heard stitched risers speed up the canopy a great deal. The people I get my information from fly JVX 89s and Velo 96s and are placing 1st in swoop competitions. They have the RDSs and Vectran lines.

Me, I am just starting to learn how to fly my Stiletto 120 before I downsize to a 107 and then I have a Jedi 105 to fly when I am done with the 107. I listen to my canopy mentors who have this gradual do this first then try this. One day I hope to fly a crossbrace but I have to start somewhere.

I am doing what I can to practice higher performance landings loaded up on weight and getting used to the mods early on something bigger so I don't do all of my learning on a handkerchief if you know what I mean ... The ground is hard.

So basically, my Stiletto 120 can be as fast and ground hungry as it likes, I am not sure what kind of change if any stitched risers will have and I won't know until I use em in Florida after Christmas cause it's too damn cold here to jump!!!

Edited to reply to Sparky: Radar guns

Roy Bacon: "Elvises, light your fires."

Sting: "Be yourself no matter what they say."

[crazydiver 0]

The reason that the canopy is more ground hungry usually is because of this...

Think about how much length of the front riser is folded and then think about how much length of the rears are folded. The fronts have more length to be folded. As with any sewing, the more stitches, the more shrinkage. If the fronts shrink more than the rears, you've got a more ground hungry canopy.

On the rears, you've got the hard housings that cant be folded as well as the spaces where the toggles are stowed, where as on the fronts you only have to avoid the dive loops.

I've seen folks play with this in varying how much is stitched. An acquantence of mine has them stitched so that the canopy is actually flatter gliding.

Cheers,
Travis

[RMURRAY 1]

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The reason that the canopy is more ground hungry usually is because of this...

Think about how much length of the front riser is folded and then think about how much length of the rears are folded. The fronts have more length to be folded. As with any sewing, the more stitches, the more shrinkage. If the fronts shrink more than the rears, you've got a more ground hungry canopy.

On the rears, you've got the hard housings that cant be folded as well as the spaces where the toggles are stowed, where as on the fronts you only have to avoid the dive loops.

I've seen folks play with this in varying how much is stitched. An acquantence of mine has them stitched so that the canopy is actually flatter gliding.

when you fold the risers lengthwise and sew they do not get shorter do they??? it is only to reduce the frontal area by a few square inches. when you are going 90mph (you are a top competitor) can be significant. Or am I missing something?

rm

[ZigZagMarquis 9]

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Edited to reply to Sparky: Radar guns

Oh great! Cops hanging around the DZ!!!

I can see it now... the next generation of ADDs will include a "Fuzz-Buster" mode.

[mjosparky 4]

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Edited to reply to Sparky: Radar guns

And how many jumpers carry a radar gun in their kit bag?

Sparky

My idea of a fair fight is clubbing baby seals

[ZigZagMarquis 9]

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Edited to reply to Sparky: Radar guns

And how many jumpers carry a radar gun in their kit bag?

Sparky

I'll bet Ivan Henry had one...

[crazydiver 0]

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when you fold the risers lengthwise and sew they do not get shorter do they??? it is only to reduce the frontal area by a few square inches. when you are going 90mph (you are a top competitor) can be significant. Or am I missing something?

They get slightly shorter because the location where the fold turns back into flat riser takes up some length. It does reduce the frontal surface area and this is the benefit. The shrinkage only occurs in a tiny amount...however...on a highly loaded canopy, having the fronts shrink 1/4 inch is going to drastically change the angle of attack of the canopy.

Think about if you had the riser folded but not stitched and you pulled on opposite ends of the riser, it would lengthen slightly.

Cheers,
Travis