Forums: Skydiving Disciplines: Swooping and Canopy Control:
Riser Length Vs. Harness Size

 


mmm_peanuts  (D 29215)

Jan 7, 2011, 9:01 PM
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Riser Length Vs. Harness Size Can't Post

I recently had the opportunity to try the same canopy/riser combination on 2 different containers; One had a slightly short harness for myself, while the other had a slightly long harness. I found that the canopy performed differently on each system, comparable to changing riser length on the same container. I have yet to fly a container designed for my frame.

I feel that this effect has yet to be addressed here and I would like more input on the subject, since many purchase used equipment that, "fits close enough".

Further more, do people with longer frames on a properly sized harness experience flight characteristics similar to shorter individuals with longer risers on the same canopy and wing loading? (ie. the distance from the canopy to the hip rings is the same)


rem

Jan 8, 2011, 12:24 PM
Post #2 of 24 (2769 views)
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Re: [mmm_peanuts] Riser Length Vs. Harness Size [In reply to] Can't Post

chest strap?


petejones45  (C License)

Jan 8, 2011, 11:28 PM
Post #3 of 24 (2691 views)
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Re: [mmm_peanuts] Riser Length Vs. Harness Size [In reply to] Can't Post

The harness could shift your body weight around and affect different parts of the canopy, also chest strap length can do that to


trigger  (D 101390)

Jan 9, 2011, 1:53 AM
Post #4 of 24 (2682 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Lengthening/letting out the chest strap after deployment allows the canopy to take its full design shape having a positive effect on the way the canopy flies. imo
An oversized harness [i guess] may have a similar effect but may also effect your ability to harness turn the canopy achieved by shifting your weight left/right in the harness.


mmm_peanuts  (D 29215)

Jan 9, 2011, 1:41 PM
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Re: [trigger] Riser Length Vs. Harness Size [In reply to] Can't Post

Chest strap would most certainly make a difference if not let fully out after deployment. However, both of the systems that I was using had fully extended, over sized chest straps. This placed the risers and harness in line with each other, placing the pivot point at the hip rings.

My thought is that, in circumstances such as this, placing the load further from the canopy (either by riser length or harness length), will create effects such as increased recovery arc.


mmm_peanuts  (D 29215)

Jan 9, 2011, 1:44 PM
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Re: [trigger] Riser Length Vs. Harness Size [In reply to] Can't Post

Also, this effect will be far more dramatic on smaller, highly loaded canopies.


floormonkey  (D License)

Jan 10, 2011, 7:41 AM
Post #7 of 24 (2542 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

The harness is an inanimate object. It does not shift your weight around, the individual sitting or hanging in the harness shifts the weight.

Your chest strap does not affect different parts of the canopy. However, loosening (or tightening or not altering the tightness of) your chest strap will change the performance of your ENTIRE canopy.

Please make sure you know what you are talking about before you give advice. Poor advice has been known to kill people.


(This post was edited by floormonkey on Jan 10, 2011, 7:44 AM)


trigger  (D 101390)

Jan 10, 2011, 9:31 AM
Post #8 of 24 (2514 views)
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Re: [mmm_peanuts] Riser Length Vs. Harness Size [In reply to] Can't Post

Might be worth noting the length of the MLW if to short for the jumper will shift the position of the hip rings[if fitted] higher up towards the jumpers waist.
Had a G4 way to small for me [made for a balding dwarf, long story] hip ring were at naval level on my waist, 20" risers, short chest strap,the thing was a nightmare to jump and my swooping suffered as the canopy recovered way to quickly from the dive.
Now jumping a made to measure rig, 23"risers, long chest strap, happy daysSmile


petejones45  (C License)

Jan 10, 2011, 3:33 PM
Post #9 of 24 (2454 views)
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Re: [floormonkey] Riser Length Vs. Harness Size [In reply to] Can't Post

if you hang differently in each harness that will for sure move your weight around


JamMasterJay

Jan 10, 2011, 4:24 PM
Post #10 of 24 (2442 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

In reply to:
if you hang differently in each harness that will for sure move your weight around

nope, but thanks for playing...yet again! like previously stated, YOU move your weight around; those weight shifts direct the harness/canopy...not the other way around.


davelepka  (D 21448)

Jan 10, 2011, 7:32 PM
Post #11 of 24 (2412 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
if you hang differently in each harness that will for sure move your weight around

Stop it. Just stop sitting there and guessing what the right answers are, and posting them as if they were facts. It doesn't make you appear smart, experienced, or even helpful, it's just annoying.

You're attached to your canopy via a single point of attachment, that being the three ring (were talking strictly about the pitch axis, the roll axis is not relevant). Whatever you try to do with your weight, or where ever you move the attachment point, your weight will center itself under that single point of attachment. There is no fore/aft weight shift possible with a single point of attachment.

A childs swing is an ideal example. Sit on a swing, and without holding the chains attempt to get a swing going. You could kick you legs back and forth to a degree, but you will enact very little change on the swing. You are attached to the swing via a single point, that being your ass.

Now reach up and grasp the chains about shoulder height, and leverge your weight forward against a rearward pull on the chains. Suddenly you swing forward. Reverse the action at the peak of the forwar swing, and you'll swing an equal or greater distance to the rear. What you have done by grabbing the chains is created the second point of attachment needed to make a weight shift meaningful. the very second point of attachment that a parachute lacks.

Look at hang gliders, which are more technically know at 'weight shift' aircraft. They operate on the principal of shifting your weight to effect change on the wing, and as such provide TWO points of attachment to the wing, one being the point the pilot hangs from, and the other being the control bar that sits in front of the pilot.

How long are going to persist in posting inaccurate information, and then getting bitch slapped becasue of it?


petejones45  (C License)

Jan 10, 2011, 7:45 PM
Post #12 of 24 (2406 views)
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Re: [davelepka] Riser Length Vs. Harness Size [In reply to] Can't Post

no... think about it, if one harness naturally causes you to lean forward more then your parachute will drive a little more(why do you think swoopers lean far forward?)

the swing method is another example if you lean forward the swing will move back.

so

regular harness= normall flight

different harness(changes body position)
= affects canopy flight


davelepka  (D 21448)

Jan 10, 2011, 7:56 PM
Post #13 of 24 (2402 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
no... think about it

I have thought it about. Far more than you have, and most likely far more than you ever will.

Ever try to push a rope? I'll bet you can tell me how that one works as well.


davelepka  (D 21448)

Jan 10, 2011, 8:02 PM
Post #14 of 24 (2400 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
if one harness naturally causes you to lean forward more then your parachute will drive a little more(why do you think swoopers lean far forward?)

Do you even give one second of thought to the shit you post? I'm surprised you can even get through typing it before you realize how stupid it is.

Why do swoopers lean forward? Ask yourself this, poindexter, when exactly do swoopers lean far forward? The answer is when competing for distance, toward the end of their swoop.

So by your genius reasoning, what every swooper is looking for at the end of distance run is a nice dive out of their canopy. You wouldn't want to find a way to make the canopy go up, or even just fly level for a little longer, no, you're going to follow P Jones's expert advice, and do something to make your canopy dive.

The most realistic answer for why a swooper would lean so far forward in the harness is drag. If you can orient your body lengthiwse to the relative wind, you'll induce less drag and fly further. Of course, that answer, being from the realm of reality, would elude you.


Martini  (D 23756)

Jan 10, 2011, 8:04 PM
Post #15 of 24 (2400 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Once again we revel in the glory of your genius! Unsure


danielcroft  (D 31103)

Jan 10, 2011, 8:11 PM
Post #16 of 24 (2394 views)
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Re: [davelepka] Riser Length Vs. Harness Size [In reply to] Can't Post

You really try Dave, amazing self control here which is a lesson unto itself.

Can't one of the mods *please* get the trolling to stop.


Martini  (D 23756)

Jan 10, 2011, 8:16 PM
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Re: [danielcroft] Riser Length Vs. Harness Size [In reply to] Can't Post

You're calling the Genius a troll? Shocked


petejones45  (C License)

Jan 10, 2011, 9:27 PM
Post #18 of 24 (2367 views)
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Re: [davelepka] Riser Length Vs. Harness Size [In reply to] Can't Post

so what you are are saying weight shift is not a factor even though i proved it with your logic... and you are giving me a bad time!!!? haha


mmm_peanuts  (D 29215)

Jan 10, 2011, 9:37 PM
Post #19 of 24 (2363 views)
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Re: [Martini] Riser Length Vs. Harness Size [In reply to] Can't Post

Please keep on topic. This harness phenominom has to do with a pendulum effect created by an increased distance between the pilots harness pivot point or load point, and the canopy. This has been brought to attention due to riser length, but not harness length. Any input on the TOTAL distance from the canopy to the load, since I feel the effect of the harness variable has yet to be addressed in canopy flight.


davelepka  (D 21448)

Jan 10, 2011, 9:56 PM
Post #20 of 24 (2360 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
so what you are are saying weight shift is not a factor even though i proved it with your logic

You proved nothing. I was being sarcastic when I said a swooper would be looking for a way to dive their canopy at the end of a distance run.

Fore/aft weight shift is not a factor in canopy contol. Your weight, in relation to the canopy, will always hang centered under the single point of attachment. It's callled gravity, and unless you have a second point of attachement to lever against, you're going nowhere.

Maybe I should be more specific, and call it a single plane of attachment, with respect to fore/aft movement. Of course there are two points attaching you to the harness, but they pivot about the same plane, so they act as a single point.

Let's literally turn this argument sideways to prove my point. Lateral weight shift does have an effect on the canopy, and that's because the two attachment points (the risers) are being moved about two different, parallel planes. Because you can isolate one of them, and move the other, you can effect real change to the canopy. This cannot be said of fore/aft movement.

Maybe you're missing the point, here at DZ.com, the point that being a knowledgable contributor to this board is not a 'thing' of in itself. It's a by-product of being an experienced and knowledgable skydiver, and having the ability to put your ideas into words in a clear, consice, and correct manner.

You seem to want to skip the part about becoming a knowledgable and experienced skydiver, and go right to being a knowledgeble and respected contributor to the board, and that's just not possible. Even if it was, who the hell would aspire to be a 'big shot' on DZ.com?

This is something that I, and I would guess the majority of other jumpers, do in between actually jumping. I would much rather be jumping, but it's dark and 12 degress outside, so instead I can talk about jumping, learn about jumping, and teach about jumping.

The thing is, your station on DZ.com is the same as your station in real life skydiving. You can certainly have a high station in skydiving without any on DZ.com, but it does not work the other way. You cannot speak with knowledge and authority, without first gaining knowledge and authority, and none of that happens on DZ.com, or anywhere besides a DZ or wind tunnel.

What you have done is bypassed reality, and gone straight to drawing your ideas from DZ.com, and then utilizing them right back on DZ.com, and it doesn't work that way becasue the internet is a terrible place to learn about skydiving. Your information is limited by the author of what you read, there ability to convey the message to you, and your ability to understand what was presented, all of which (even in the best case scenario) are a pale comparison to the stark reality of the physical truths to be found while ACTUALLY JUMPING.

Again, read more. Ask questions. Develop theories and present them as theories. Participate in non-jumping discussions to your heart's content. But for the love of god, shut your mouth when it comes to offering difinitive answers to anything related to skydiving. You simply do not have the time in sport, number of jumps, or depth of knowledge to be able to do that accurately, and it's a real pain the ass to correct your mistakes, over and over again.


petejones45  (C License)

Jan 10, 2011, 10:07 PM
Post #21 of 24 (2354 views)
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Re: [davelepka] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
What you have done is bypassed reality, and gone straight to drawing your ideas from DZ.com, and then utilizing them right back on DZ.com, and it doesn't work that way becasue the internet is a terrible place to learn about skydiving. Your information is limited by the author of what you read, there ability to convey the message to you, and your ability to understand what was presented, all of which (even in the best case scenario) are a pale comparison to the stark reality of the physical truths to be found while ACTUALLY JUMPING.

you just burned yourself with your own logicSmile

i still stand by my posts that weight shift is a factor


davelepka  (D 21448)

Jan 10, 2011, 10:10 PM
Post #22 of 24 (2353 views)
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Re: [petejones45] Riser Length Vs. Harness Size [In reply to] Can't Post

Quote:
i still stand by my posts that weight shift is a factor

The cheese stands alone


Martini  (D 23756)

Jan 10, 2011, 10:22 PM
Post #23 of 24 (2351 views)
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Re: [mmm_peanuts] Riser Length Vs. Harness Size [In reply to] Can't Post

OK. I see three ways to change the distance from canopy to jumper center of mass:

Line length
Riser length
Harness length

Since line length is typically fixed you can control the other two. Assuming the harness fits reasonably well the only user-variable component is riser length. I believe that the total canopy to center of mass length having an effect on pendulum swing is fairly well established, changing this length through a grossly ill-fitting harness may be apparent but doesn't seem useful. Do you think that the average jumper would notice a performance change by increasing overall length of only a few inches? My guess that a 3-4 inch change is only really noticeable on a canopy with really short lines (read really small canopy) and only when flown aggressively. My set of too-long-for-me risers don't seem to have any effect on a Sabre at 1.6+ even with the hammer down, never tried them on the Xaos though.


mmm_peanuts  (D 29215)

Jan 10, 2011, 10:47 PM
Post #24 of 24 (2345 views)
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Re: [Martini] Riser Length Vs. Harness Size [In reply to] Can't Post

I definitely agree that this is NOT a recommended way to control canopy flight characteristics, but it is something that can effect people in equipment changes. This, I am assuming, is most noticable at high wing loadings. I experienced a noticeable difference in flight switching between C-16 and C-18 harnesses, with ideal C-17 @ 2.0. This is a reasonable fitting on both systems, which is something that may be experienced by people using used equipment.



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