aerodyne 3 rings

[agent_lead 0]

i have an aerodyne icon container...

i was wondering if anyone knew...in detail...the reasoning behind there modification of bill booths system...

they say it takes less force to chop...but i mean..it only takes 6 pounds of pressure to chop a reg 3 ring...and aerodynes system takes 5.7 pounds..

dont you think when it comes time to chop you are exerting way beyond 6 lbs of pressure to begin with??

plus the round circles cant get locked up...but it seems plausible that aerodynes design may be able to ...

but who would ever know that from the guy laying dead on the floor...why he burned in...when all the pressure is gone..and everything looks normal??


please advise..

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[Pawel 0]

Same web site you provided has the answers you seek. Read on.

[http://www.flyaerodyne.com/download/miniforce.pdf]

[mjosparky 4]

A good rule of thumb: Any change should make a major improvement in function or safety of the equipment.

I fail to see where Aerodyne’s Miniforce 3 ring system does either. They are a solution to a problem that did not exist in the first place.

My idea of a fair fight is clubbing baby seals

[tbrown 26]

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A good rule of thumb: Any change should make a major improvement in function or safety of the equipment.

I fail to see where Aerodyne’s Miniforce 3 ring system does either. They are a solution to a problem that did not exist in the first place.

Yeah, but they had the temerity to rub it in Bill Booth's face with a special "lifetime award" they gave him for inventing the 3 Ring so they could "improve" it.

Their claim seems to be with spun up high performance mains, which are a real bitch to cutaway, witness the recent innovation of hard cable housings on risers. They claim their new design significantly lowers the pull forces required for chopping highly loaded postage stamp divebomber canopies. I don't have the expertise to say yea or nay, but in general there ain't nothing that can't be improved on, so I'm not ready to completely dismiss the idea.

Your humble servant.....Professor Gravity !

[mjosparky 4]

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Their claim seems to be with spun up high performance mains,

The high cutaway forces associated with line twists have nothing to do with the rings. It is the cable being trapped in the channel on the riser. The culprits in this scenario are highly loaded elliptical canopies attached to Type 17 mini riser. Changing the design or configuration of one or more of the rings will not prevent this from happening. The hard inserts in the riser channel address this problem.

They claim a 57% reduction is the force needed to cutaway with 675 pounds on each riser. Their tests show 7.82 pounds of force on regular 3 rings and 3.34 pounds on the Miniforce rings. That a reduction of 4.48 pounds. The TSO-C23d requirement for a cutaway system if used is 22 pounds. It seems to me that with such a small reduction their “new” rings are more fluff than function. I have also heard, no proof, that they do not allow mix and match of other rings on their containers.

My idea of a fair fight is clubbing baby seals

[feuergnom 28]

just to make shure i get you right: by "mix and match of other rings" you mean that the usage of risers from other anufacturers is prohibited?

that would - IMHO - be a wise decision. i am pretty shure you know what happened when people installed reverse risers on rigs other than in the original configuration. guess aerodyne wants to prevent similar experiences

The universal aptitude for ineptitude makes any human accomplishment an incredible miracle

dudeist skydiver # 666

[mjosparky 4]

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you mean that the usage of risers from other anufacturers is prohibited?

Yes, that is what I mean. Reverse risers were an attempt to fix a problem that was created when one component was substituted in the original 3 ring “system”.

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guess Aerodyne wants to prevent similar experiences

They have created the opportunity to have the same experiences. The 3 ring “system” has proven it worth over and over again. What Aerodyne has done is take one component out of that “system” and replaced with one of their own design. It appears to me to be an attempt to fix something that is not broken.

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be a wise decision.

It prevents demoing other canopies and makes that rig the odd man out in the container world. The 3 ring “system” has become the standard through out the industry because it works. What have they gained?

My idea of a fair fight is clubbing baby seals

[brabzzz 0]

If you're concerned with cutaway forces, get big rings. Miniforce seems like an attempt to make something looks shiny, different, cute, small and cool - and market it as safer too. The original rings work. To make them safer, you scale them up and make them bigger. Why complicate stuff by reshaping it? Seems like reinventing the wheel for the sake of it.

---------------------------------------
Ex-University of Bristol Skydiving Club
www.skydivebristoluni.com

[koppel 4]

I have read and agreeded with most of what people have written here regarding 'why change a system that is the standard and works'

my 0,02c here is that it appears to me that they are trying to bring back the benifit of the larger rings while trying to appease the general skydiving community with something that looks "good". As Bill is heard to have quoted Skydivers buy fashion not safety.

Bill has stated that the larger rings can be manufactured with more tolerance than the smaller rings.

My speculation is that Aerodyne has attempted to create that by making a ring that has the diameter of the larger rings in a smaller package.

Not being a technical type of person I am not sure if this can work. Any better brains than mine out there care to comment?

I like my canopy...


...it lets me down.

[airtwardo 7]

To make them safer, you scale them up and make them bigger. Why complicate stuff by reshaping it?


***

IMO it's basically a lever system, it was probably designed round in the first place to make it easy to manufacture without the need for aerospace type tolerances.

I 'looks' to me like what they did was make the riser part of the lever system longer in order to ultimately lessen the force on the last fabric loop, decreasing the tension against the cut away cable...

Am I looking at this right?

~ If you choke a Smurf, what color does it turn? ~

[IanHarrop 41]

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It 'looks' to me like what they did was make the riser part of the lever system longer in order to ultimately lessen the force on the last fabric loop, decreasing the tension against the cut away cable...

That appears to be what they are saying

http://www.flyaerodyne.com/download/miniforce.pdf

"Where troubles melt like lemon drops, away above the chimney tops, that's where you'll find me" Dorothy

[LouDiamond 1]

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It prevents demoing other canopies

How is that? If you remove the canopy and risers you are left with the large base ring which is found on all rigs. There is nothing different about the Base ring that would prevent someone from putting another set of risers/canopy on the container. I have watched scores of people demo Aerodyne canopies on Aerodyne risers in their own rigs and I have seen people put other canopies on normal risers into Aerodyne containers and jump them without problem.

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[SkymonkeyONE 4]

Moving this to G&R

Chuck

[ernokaikkonen 0]

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The high cutaway forces associated with line twists have nothing to do with the rings.

Sure they do. The smaller the rings, the larger the forces. Of course, compared to the difference hard housings make the size and type of the rings may not make much difference.

Here is a chart on 3-ring loads and pull forces that I compiled from information available on the RWS and Aerodyne websites.

[matt91078 0]

What about not having to pay for the use of the three rings patent since it's their own design? Just a thought?

[justinb138 0]

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What about not having to pay for the use of the three rings patent since it's their own design? Just a thought?

I don't think anyone's been paying for using the three ring design for quite a long time, if ever.

[riggerrob 643]

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To make them safer, you scale them up and make them bigger. Why complicate stuff by reshaping it?


***

IMO it's basically a lever system, it was probably designed round in the first place to make it easy to manufacture without the need for aerospace type tolerances.

I 'looks' to me like what they did was make the riser part of the lever system longer in order to ultimately lessen the force on the last fabric loop, decreasing the tension against the cut away cable...

Am I looking at this right?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Yes.
I remember standing beside Bill Booth when Aerodyne unveiled their mini-force rings at the 2005 PIA Symposium. Bill commented that you could achieve the same result by carefully-sizing the white nylon loop.
For dimensions of white nylon loops, look at the 3-Ring manual published by Relative Workshop/3-Ring Inc. in 1998.

[riggerrob 643]

Compatibliity clarification: you can install mini-ring risers from most other manufacturers on Icon harnesses, but be careful when installing mini-force risers on harness made by other companies, because the cutaway housing might be too short.

You see ... mini-force risers are longer - from the harness ring to the small ring - requiring cutaway housings and cables an inch or so longer. The good news is that most manufacturers make their housing slightly too long.
When installing mini-force risers on another harness, test them by pulling the riser in all directions to ensure that you never load the metal cutaway housing.

This question was answered in an Aerodyne Service Bulletin last year.

[billvon 2,990]

>The high cutaway forces associated with line twists have nothing to do with the rings.

Sure they do. During a heavily loaded (3+ G) cutaway scenario, the higher forces on the rings translate to a higher force on the white loop, which makes it more difficult to extract the cable. In extreme cases you get "cable suck" which starts sucking the cable through the grommet, rendering a cutaway nearly impossible.

Fixes include:

1. More mechanical advantage in the system. Both the Aerodyne system and a larger ring assembly could help with this.
2. Cleaned and lubricated cables; make them slide more easily.

You may also have the additional problem of getting the cables trapped; hard housings can help there as you mentioned.

>It seems to me that with such a small reduction their “new” rings are more fluff than function.

Right, but during a bad spinner (even with hard housings) that 57% reduction could mean the difference between 18 and 40 pounds - which might be significant.

This isn't to say that their system is in every respect better than the current mini-3-ring system; it's just one more option that people have. Use in the field will result in data that we can use to determine whether or not it's a good idea or not. I have a feeling that fashion will play at least a minor role - after all, large 3-rings work very well but aren't popular mainly because of cosmetic issues.

[mark 107]

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Right, but during a bad spinner (even with hard housings) that 57% reduction could mean the difference between 18 and 40 pounds - which might be significant.

IIRC from the last PIA Symposium -- and as I read the pdf file on Aerodyne's website -- the 57% max (average 37%) reduction was measured at the white loop, not where the cables emerge from the housing at the breakaway pillow. If so, they measured only part of the total pull force; the actual reduction in pull force would amount to only a few pounds.

Mark

[billvon 2,990]

>the 57% max (average 37%) reduction was measured at the white
> loop, not where the cables emerge from the housing at the
> breakaway pillow.

Hmm. Wouldn't you expect them to scale linearly, though? (i.e. double the force at the white loop, roughly double the friction.)

>If so, they measured only part of the total pull force . . .

Agreed, but the residual pull force is due to the drag on the other housings and system components, and that seems like a small part of total drag.

[riggermick 7]

I don't think anyone's been paying for using the three ring design for quite a long time, if ever.

[mark 107]

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>If so, they measured only part of the total pull force . . .

Agreed, but the residual pull force is due to the drag on the other housings and system components, and that seems like a small part of total drag.

It seems to me that friction of cables inside curving cable housings would be a substantial part of the total resistance. I don't know what the facts are, though.

You and I disagree about the distribution of drag forces acting on the cutaway cables in actual use, but we're both in "seems to me" mode. Do you know of any tests, studies, or manufacturer's statements that address the issue?

Thanks,
Mark

[AndyMan 7]

Bill Booth actually tested the Aerodyne miniforce rings. He posted his results here: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=1636917;.

Quoting Bill Booth:

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I just went back and did a side by side pull test with our standard mini riser and the Miniforce riser. The set-up was a single riser, with the yellow cable through a short stainless housing. Here are the results (average, 3 tests each weight):


250 lbs. load - Standard = 2.0 lbs / Miniforce = 1.0 lbs.
500 lbs. load - Standard = 3.0 lbs. / Miniforce = 2.0 lbs.
750 lbs. load - Standard = 5.0 lbs. / Miniforce = 3.5 lbs.
1,000 lbs. load - Standard = 8.0 lbs. / Miniforce = 6.0 lbs.

So, if a 200 lbs. jumper was spinning at 5 "G's", (500 lbs. on each riser) the miniforce riser equipped rig would require 2 lb. less pull force to breakaway...or 4 lbs. vs 6 lbs., plus housing friction. I doubt the average jumper would be able to tell the difference.

_Am

__

You put the fun in "funnel" - craichead.

[billvon 2,990]

That's a good bit of info. So it sounds like the Miniforce requires between 50% and 75% of the pullforce of the standard riser, depending on loading.