Hypothetical Slider Discussion

[bomb420 1]

So I was just reading the RDS thread from the swoop forum and asked myself, is there another way to slow down the opening of a canopy without a slider?.... Now before you flame me, this is just a hypothetical question. Instead of using air resistance can we come up with another mechanism to use? Just seems this method has been around for years without really any dramatic changes. Hell, perhaps there will be no need for an RDS.

Just a dorky engineer pondering...

HYPOXIC

[phoenixlpr 0]

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is there another way to slow down the opening of a canopy without a slider?....

Sure they were. The slider was not the first try, but it turns out the most reliable and foolproof. Why do you want to fix something not broken?

[madhatter 0]

"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man."
George Bernard Shaw

A VERY MERRY UNBIRTHDAY TO YOU!!!
D.S # 125

[phoenixlpr 0]

I have a feeling that some people quote others because they don't have own ideas. What did you want to say?

[madhatter 0]

I was just trying to illustrate that it's human to wonder if there isn't another (better?) way to do something. Horsedrawn carriages worked fine, why build automobiles?

I've been ragged for changing or wanting to change virtually everything I lay my hands on. I've paid lot's of 'school fees' everytime I stuffed it up, but sometimes my changes are actually improvements, so I stay curious.

Let our 'dorky engineer' wonder about a replacement for the slider, he might just turn out to be the next Bill Booth

A VERY MERRY UNBIRTHDAY TO YOU!!!
D.S # 125

[phoenixlpr 0]

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Let our 'dorky engineer' wonder about a replacement for the slider, he might just turn out to be the next Bill Booth Tongue

I think our 'dorky engineer' should check previous unsuccessful designs for learn from them and try not to re-invent them.

I still don't get what is wrong with the slider?

[madhatter 0]

We've progressed from a slider being just something to seperate linegroups, to understanding sizing & pockets on sliders and their effect in controlling openings, to removable sliders. Who are you & I to say it can't progress any further.

There's nothing wrong with a slider, just as there's nothing wrong with investigating new concepts (whilst taking into account & learning from earlier unsuccessful designs).

Rounds worked, why did we change to squares, then to ellipticals, then airlocks & x-brace? All because someone wanted to try something new. Who knows what new developments we're going to see during our skydiving lives...

Exciting, isn't it?

A VERY MERRY UNBIRTHDAY TO YOU!!!
D.S # 125

[JohnRich 4]

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Instead of using air resistance can we come up with another mechanism to use?

I have this idea for something I'd call "rings and ropes"...

[DJL 232]

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I have a feeling that some people quote others because they don't have own ideas. What did you want to say?

I think that's a great quote. Mind if I use it?

Also, there are plenty of places this could go. There could be an advancement in canopy that design that when coupled with another technology would make the slider obsolete. Perhaps a system on the bottomskin of the canopy, a combination slider/d-bag, a modification on a tailpocket...

"I encourage all awesome dangerous behavior." - Jeffro Fincher

[riggerrob 558]

You could jump a (square) canopy all day without a slider as long as you never took it to terminal velocity.
BASE jumpers do that every day.
By reducing the size of nose openings, adjusting brake settings, etc. you might be able to make a square canopy open softly - at terminal - but it would be tailored for only one speed. At any other speed it would snivel or snap.

Lots of other reefing methods have been tried over the years.
I have jumped an OSI and roped Strato Cloud.

The OSI was just a wide piece of webbing - lined with Teflon - that was wrapped around the top of the suspension lines on Delta II rogallo canopies. But it did not work very well. Out of four sub-terminal openings, three hurt!

Riggers experimented briefly with hydraulic reefing systems, but never got them to operate consistently at both the high speed and low speed edges of the envelope.

The next reefing system I tried was ropes and rings. That was one of the few canopies I enjoyed deploying from a track, but I hated packing it! The disadvantage was that it packed HUGE! And if you did not pack it precisely, the rope tended to tangle.

A simplified version of ropes and rings was the pilot chute controlled slider, basically a rope tied to the bottom of the pilot chute and the top of the X slider. The rope was routed straight down through the center of the canopy. Some military HAHO and HALO jumper still use double-length PCCS, because they work better at the high speed edge of the envelope.

The primary reason that sail sliders have dominated skydiving since the late 1970s is that they are almost idiot-proof.

[DrewEckhardt 0]

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So I was just reading the RDS thread from the swoop forum and asked myself, is there another way to slow down the opening of a canopy without a slider?.... Now before you flame me, this is just a hypothetical question. Instead of using air resistance can we come up with another mechanism to use?

No, but you could apply the resistance differently.

Maybe ropes and rings with a non-collapsible pilot chute and kill cone tethered to the canopy top skin so it can't stop the pilot chute drag until the parachute has slowed down enough its mostly deployed.

Of course, some one who is already removing the (minimal) drag of their collapsed pilot chute isn't going to live with that.

[Colson 0]

I saw a "design" somewhere that I never got to read in full but the abstract was slider improvement with an addition of a device to a sail slider that would increase the friction between the suspension lines and slider. I assume the idea was to assist the aerodynamic forces on the slider in retarding the spread of the canopy to allow the designer more precise control over the canopy reefing process, specifically time. Obviously wear would appear to be an issue with this.

[bomb420 1]

Just was watching people reconnect RDS' this weekend and seemed tedious and a long process. Now if a streamlined system could be made not requiring a slider....

Guys,
Thanks for the history lesson. I need to look up all those past methods.

-Trunk

HYPOXIC

[Beatnik 2]

You think the OSI is bad, you should be glad you haven't jumped a hydraulic reefing canopy. I have never had such a violent opening. Somehow I got a black eye from it.

There was also the Raeford diaper as well. Never jumped a canopy in that configuration.

With rings and ropes there were two types. Top surface and bottom surface. I haven't had a chance to jump my Strato-Star but have been told that the underside rings and ropes work better than the top surface. Judging from my experience with my Para-Plane, I would be willing to believe it.

If someone wants to take a kick at it, I think they should give it a go. It doesn't hurt to try new things and maybe something new will be invented. Greg Yarbenet invented the slider in 1973. That is 35 years without any major changes.

I am willing to bet that there were other ideas that never hit the market and maybe disappeared from the records. You can't advance unless someone is willing to try something new.

[mvidovic 0]

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You could jump a (square) canopy all day without a slider as long as you never took it to terminal velocity.
BASE jumpers do that every day.

Great advice! How many slider off jumps do you have in the 4-7 sec delay range?

I'm married to the devil himself!

[dumstuntzz 0]

why do you want to fix something that simply aint broke?......if any of you were around in the sport 35-40 years ago you would have seen dozens of different ideas that were used to try to slow down the openings.the slider is still around because it is the most reliable,and simplest device .period.

[phoenixlpr 0]

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The slider was not the first try, but it turns out the most reliable and foolproof.

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the slider is still around because it is the most reliable,and simplest device .period.

So ? Have I stated in my first post? I still don't get what you did want to say.

[DougH 270]

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The slider was not the first try, but it turns out the most reliable and foolproof.

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the slider is still around because it is the most reliable,and simplest device .period.

So ? Have I stated in my first post? I still don;t get what you did want to say.

Since when did you become the only one on dz.com who can post one or two line quips mostly devoid of content Gabor?

"The restraining order says you're only allowed to touch me in freefall"
=P

[RiggerLee 61]

Some of the most cutting edge designs do not use sliders. A lot of the heavy drop canopies, very large squares, do not use sliders. They are just too big and too complex. Too many cells. The diffrence between cell width and span is too great. Some of them use cutters to stage the opening letting the center spread first and progresively to the out side. This idea is not new it's used in larger rounds as well.

Lee

Lee
[email protected]
www.velocitysportswear.com

[phoenixlpr 0]

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Some of the most cutting edge designs do not use sliders. A lot of the heavy drop canopies, very large squares, do not use sliders. They are just too big and too complex. Too many cells. The diffrence between cell width and span is too great. Some of them use cutters to stage the opening letting the center spread first and progresively to the out side. This idea is not new it's used in larger rounds as well.

AFAIK they drop cargo and not people. A human might not survive that deceleration.

[relyon 0]

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... A human might not survive that deceleration.

I don't know for certain, but I'll guess it may be just the opposite. I have a friend who did parachute work on the X-38 and currently works on Space Shuttle booster parachute recovery. I'm curious and will ask.

Things not needing fixed because they aren't broken is a poor excuse for not innovating. Capewells worked fine as releases before three rings; caves worked fine as shelter before houses. I doubt anyone wants to return to using either.

Bob

[RiggerLee 61]

That in no way implies high deceleration. In fact I'd wager the g forces are much lower. When the mass is that high you can not risk a spike in deceleration. In fact if you were to tag along I'd bet it would be the smoothest ride you ever had. The mass acts as a damper. I wouldn't hesitate to ride along on one of those drops.
However brought the whole thing up as just an example of a nonaerodinamic reefing system.

Lee

Lee
[email protected]
www.velocitysportswear.com

[UDSkyJunkie 0]

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is there another way to slow down the opening of a canopy without a slider?....

Hmm... if we rigged up a series of rings around the perimeter of the canopy and ran rope through it... oh wait, that's been done already...

If you dont' know what I'm talking about, go find the oldest guy on the DZ and ask him how much ropes and rings sucked! Then ask about the "opening shock inhibitor" design on the Delta II. Malfunction rate ~33%. (no, I'm not kidding)

"Some people follow their dreams, others hunt them down and beat them mercilessly into submission."

[Gawain 0]

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So I was just reading the RDS thread from the swoop forum and asked myself, is there another way to slow down the opening of a canopy without a slider?.... Now before you flame me, this is just a hypothetical question. Instead of using air resistance can we come up with another mechanism to use? Just seems this method has been around for years without really any dramatic changes. Hell, perhaps there will be no need for an RDS.

Just a dorky engineer pondering...

Well, knowing what the slider does, the trick would be to find a why to inflate the canopy slower. Off the top of my head, I would think smaller crossports near the center cells, and perhaps a progressively different arrangement along the leading edge of the canopy.

I'm not an engineer, so I'm sure none of my input is really new...

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[Beatnik 2]

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If you dont' know what I'm talking about, go find the oldest guy on the DZ and ask him how much ropes and rings sucked! Then ask about the "opening shock inhibitor" design on the Delta II. Malfunction rate ~33%. (no, I'm not kidding)

You don't always have to find the oldest guy. I tell you rings and ropes and the OSI aren't as bad as some of the things tried. I got to do a jump with a hydraulic reefing device. I don't know what the hell happened on that deployment it was so fast and violent, I hardly knew what happened. Something hit me hard during it and left a pretty good shiner.