Stitched risers?

[NoShitThereIWas 0]

This is also posted in the Gear and Rigging Forum:

OK so I am looking for some feedback from swoopers and riggers on what their opinions are of stitched risers and how they affect the performance of the canopy. Any physics savvy 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."

[marks 0]

they reduce drag.

it wont do anything really unless you reduce drag in many places, like

line thickness
clothes
bag and pilot chute removed
slider removed
stabilizers removed.

you get the picture?

it all adds up but just the risers alone don't make any difference that you will notice, plus it makes it harder to land with rears.

[davelepka 4]

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they reduce drag.

In that other thread they're saying that stiching them down will alter the length enough to effect the trim of the canopy.

One poster claimed he new of a jumper who used this effect to 'tune' his canopy.

I'm quite skeptical of this.

[bob.dino 1]

If the shrinking caused by stitching the risers noticably affects the trim, wouldn't it be easier to simply make & attach a pair of longer soft links to the rears to get the same effect?

[AndyMan 7]

I've never heard of stitching risers.... what are they stitching?

_Am

__

You put the fun in "funnel" - craichead.

[Kimblair13 0]

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I've never heard of stitching risers.... what are they stitching?

Yeah, wtf? Does someone maybe have a pic?

[frost 1]

I believe it involves folding the risers in half length wise and stiching them all the way along the fold. Theoretically, cutting on drag by making the area of the risers facing the relative wind half as wide.

Nothing real in terms of gaining anything in skill level and probably more of a gimmick then anything else, i think. Top pilots might benefit from it, but most average pilots who do it are just blindly following the leaders. Not much unlike when they strap an extra 40 lbs of weight or get RDS. They mod their gear as a shortcut to results they might show if they only made an extra 500-1000 jumps.

SoFPiDaRF - School of Fast Progress in Downsizing and Radical Flying. Because nobody knows your skills better than you.

[swoopster33 0]

The only reason is to reduce drag.

It is true that stiching the risers can cause shrinking and change the trim. The reason is that you can stich more of the front riser than the rear riser because the toggles take up room on the rears. So, you are stiching 3/4 of the fronts, and only 1/2 at most of the rears. I have a pair of 20" risers and 24" risers that this has been done to. On both sets, the fronts are 3/8 of an inch shorter than ther rears. That has changed the pitch of the canopy by 3/8 of an inch steeper on a velo.

I would advise to not try this. It can change the trim on your canopy. If you try this, take a look at the risers when you are done. Are the fronts shorter or longer? A friend of mine stiched his so that the rears are a little shorter than the fronts. So in his case, the canopy has a little flater glide. I noticed that my front riser presure whas ligher, rear riser presure was a little more, and i lost lift at the bottom end. I could also dive the canopy harder and faster with less presure on the fronts. These changes may have something to do with changing from 20's to 24's.

In the end, unless you are useing an rds, have hma lines, swooping in a tight suit, it wont help much. Most would be better off working on technique!

[marks 0]

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In the end, unless you are useing an rds, have hma lines, swooping in a tight suit, it wont help much. Most would be better off working on technique!

so look who popped in.!!!

• Quote

[swoopster33 0]

every now and then....

[NoShitThereIWas 0]

Hey Frost:

Take it easy there. I posted this to get information from experienced people after a conversation I had with some of my swoop buddies. I am trying to understand how stitching risers affects canopy flight and performance if it does. I appreciate your opinion and I understand the point you are trying to make. However, I am not talking about swooper wannabes here. I am trying to understand a concept. Thank you.

Blue skies and carry on.

Thanks Swoopster for the info that makes a lot of sense and also correlates to another poster on my other thread in Gear and Rigging. It also helps me to understand how the stitching and length of stitching affects the glide under canopy. I am already being asked to stitch risers for some of my friends and I want to understand what I am doing first. Additionally, I am getting ready to hook up a pair to a smaller canopy of mine and was curious how if any they affect performance.

They are a friend's who has an extra set of risers and I just happen to need a set. Yes he is a top notch swooper and no I am not. I am just a "swooper in training", so it's not like I need em or anything. I am also a rigger and wanting to hear people's opinions who have experience with this.

Thanks again for everyone's input.

Roy Bacon: "Elvises, light your fires."

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

[frost 1]

PM sent

SoFPiDaRF - School of Fast Progress in Downsizing and Radical Flying. Because nobody knows your skills better than you.

[swoopster33 0]

No problem on the info, hope it helps. Just remember that this can change the pitch of the canopy. If you put on a pair of risers that are different lengths due to stiching (or anything that changes the pitch or tirm of a canopy) play with it up high a lot before doing anything close to the ground.

Stay safe and see you over the pond sometime!

[riddler 0]

Howdy Jason! Did you notice a difference when you went to the stitched risers? Would that be reducing the width of a one-inch riser to a half-inch? Seems too small to make a noticeable difference ... But maybe at the ultra-competition level it may give you an extra couple of feet?

Trapped on the surface of a sphere. XKCD

[swoopster33 0]

When you stich the risers they go from 1 inch of surface area to about 3/16 of surface area. There is a substantial difference in surface area. However, as stated previously by myself and marks, the difference will only be noticed if you already have an RDS, HMA lines, tight swooping attire, (not a freefly suit) ect. What i noticed the most was the changes caused by the trim change. I am still not completely used to it and not sure if i like it. The canopy is easier to keep in a dive, but i don't have the bottom end that i did. Again, if you stich risers, be sure to pay close attention to trim changes. Play up high.

[SkymonkeyONE 4]

Didn't you just say you went up to 24's? The reason your canopy is staying in a dive longer is because of those longer risers.

I am going to go ahead and state that I don't think any riser mod that changes the trim of them is a smart idea. Yes, you could then do the old-school fix by putting slinks on one end and longer rapides on the other (like was done in Daytona and Venezuela by at least two people I know), but more to the point: I would like to know the effect that this stitching has on riser integrity. Every manufacturer has pull-testing equipment these days, so I wonder if any have done such testing? If I were wearing a bunch of lead (I don't, ever), then I would be very hesitant to take risers modded like this to terminal (or near terminal) without first knowing if their integrity was compromised in any way. If you don't think you will ever reach terminal velocity in competition you are sadly, sadly mistaken. First out on a pass of four (especially after the first pass out of an Otter) will generally always have to take at least a ten second delay. Just stuff to think about, guys.

Are you jumping those risers on every jump, or just hop and pop swoops with all your comp RDS stuff hooked up? If it's more of a pain in the ass to get a good grip on your rears, then I think it's probably counterproductive at best, but you young guys feel free to work that out. Me? the only time my full RDS is on is for distance and speed rounds in "classic" competition. It's not on for Accuracy and it is certainly not on for short ponds. I pull my slider off everytime, but keep my RDS lines rolled up in my mudflap most of the time.

Chuck

[swoopster33 0]

I noticed the canopy was easier to keep in a dive on the 20's as well. The 24's just compounded it.

I agree with you, i would not advise doing this either as i have already stated. There are many reasons i would not advise doing this, you have added some good points as well. If a manufacutre wants to start testing this concept and then puts it out on the market, then cool. But in my opinion, i don't really think it is worth it.

I have taken this to terminal many times, and the other guys i know that have the same set up have done the same with no problems. Obviously, that donsn't mean much as my risers are new. Lets see how they hold up over a few hundred jumps. I will say that i don't think the extra stiching would cause a the risers to be any weaker, but i very well could be wrong.

I also only use my full RDS on competition jumps. The rest of the time my RDS lines are rolled up in my pocket and i do take the slider off every time as well. I have not felt that the risers are harder to get a good grip on, just a little different.

Chuck i agree with you, if someone did some testing and proved that it had no effect on the strength of the risers, and this didn't cause trim changes, then i think it would be a good idea for pilots that were trying to get just a little tiny bit more out of it. But as several of us have already stated, most of us just need to keep working on form! In the end, not worth it.

I hope you get to come to Denver this year. Missed you last year.

Jason T