Cutaway from 100ft

[Frenchy68 0]

In the August issue of Skydiving mag, there is a small bit about someone intentionally cutting away from his main at about 100ft AGL last year at Cross Keys. I understand it was performed on a non production rig, slider down, and with a modified skyhook (I also understand this jump was NOT sanctioned by the maker of the rig). Is that something that is seriously into research (cutting away "safely" that low), and if so, how far into it is it? Does anyone have any more info on this?

Nick

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

[DJL 232]

Stunt, not a skydive.

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

[Frenchy68 0]

Totally agree. But not an irrelevant stunt. I am curious to find out how far into development such a concept is (from rig/canopy manufacturers)

Nick

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

[mr2mk1g 10]

Well I guess it's here now in a way. With the skyhook you reportedly have an open reserve in 78ft. That's not a figure you'd be wise to rely on mind.

[Frenchy68 0]

But knowing one can cut away <400 ft and know there will be a fully inflated reserve up one's head with "still" a couple hundred feet before touchdown? Is that really happening, or is it still in development? If so, how far into it is it?

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

[mr2mk1g 10]

Like I said - skyhook equiped rigs consistently produced an open reserve in less than 100ft during testing. No one is going to start relying on those figures just yet though - even the manufacturer doesn't advertise them or seek to rely on them. To adjust emergency proc simply because of them would be silly, it's better to keep that margine of error.

Perhaps in a few years time when we all have modern reserves and skyhook type systems in our rigs people will routinely be able to chop lower... but to rely on it to that extent just yet is not a good idea.

Still in development? Not really, the technology's already there; its simply got to earn our trust before people will start relying on it to the extent of lowering their cutaway altitudes.

[Frenchy68 0]

Thanks for the feedack.
1/has it been tested at terminal? If so, from what altitude?
2/I would definitely NOT rely on it, but the fact that there MAY be a device in the near future that will enable one to cutaway from 500 ft AGL (or below) and have a reserve opened by 300ft is quite a breakthrough. Or at least I would think so.

Nick

"For once you have tasted Absinthe you will walk the earth with your eyes turned towards the gutter, for there you have been and there you will long to return."

[mr2mk1g 10]

1) The skyhook doesn't factor into terminal reserve deployments. If you deploy your reserve without having a main out the skyhook simply unhooks itself from the reserve system - hence the name. Therefore terminal hard deck will never change due to this development.

2) It's not really likely that people will rely on the skyhook to the extent of lowering their cutaway altitudes to such extremes anyway (you'd hope anyway). There's simply too much going on during a deployment to say conclusively it will definately work in time @ 200ft simply because you have a gizmo.

Chaos theory and Sod's law combine so that when you really need that snap opening, something might just snivel for a bit due to a weird bit of wind, an odd bungee or whatever.

Then again, if the main's not landable @ 400ft, it's not landable.... you'll do what you have to and the skyhook will help to stack your deck.

[Remster 24]

Search the forums... It was discussed when the stunt was done.

Remster

[flypunk 0]

There is no way to know that your reserve will open and fully inflate in 78ft. The skyhook's one and only purpose is to extract you reserve. The rest depends on your rigger, type of reserve and a bunch of factors that you dont control. What if you have line twist, broken lines, line overs or some kind of problem at 78 ft ?

...

[base698 1]

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Well I guess it's here now in a way. With the skyhook you reportedly have an open reserve in 78ft. That's not a figure you'd be wise to rely on mind.

Keep in mind that is not necessarily a fully inflated, pressurized canopy. IE. if hit the ground in that configuration you will likely die.

[FrogNog 1]

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There is no way to know that your reserve will open and fully inflate in 78ft. The skyhook's one and only purpose is to extract [to linestretch - Frognog] you[r] reserve.

And on top of that, the skyhook is a piece of equipment and like all the rest of the equipment we use, it can fail, malfunction, or operate unexpectedly. The makers do the best they can, but in this sport there are no guarantees except the ground is waiting.

-=-=-=-=-
Pull.

[billvon 2,435]

>I am curious to find out how far into development such a concept is
> (from rig/canopy manufacturers)

It has been developed. The Sorcerer BASE container will static-line the reserve off the main (a la Skyhook.) I have seen demos from the NRGB in which the reserve was open within about 30 feet; just over the length of the reserve lines. The reserve was a BASE canopy packed slider-down.

This is of dubious value for skydiving, since a terminal slider-down opening would likely be fatal. Do you want a reserve you can't use for a total mal? You could have a selectable reefing system (i.e. a sensor would cut the riser grommets away from the lines with CYPRES type cutters if cutaway speed was low) or have two reserves, but with that level of complexity you're more likely to cause equipment failure than with a simpler system.

[LearningTOfly 0]

Just two pennies from a novice...

I would imagine that the two options availiable are to have your reserve arranged to open 'conventionally' (300-400 feet) or to open lickety-split (in less than 150' or whatever). The fast opening option would be a fine to go with if the malfunction were to be a lineover or a spinup- where you have already decelerated from terminal a great deal. But if one day your main deciedes to be really stubborn and not come out of it's bag- well, now you're set up to slow from 100+mph to 14mph in 150 feet... and send your chiropractor's kid to college shortly thereafter.

IMO the only way to stay out of trouble is to keep your options open and make decisions while you're high... if there's one thing I've learned in this sport it's that when sh*t happens, it dosen't wait for the jumper to figure out what's going on. But then again, I haven't witnessed first hand how fast the trees get big after the cutaway, touch wood.

[piisfish 135]

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Thanks for the feedack.
1/has it been tested at terminal? If so, from what altitude?

Nick

as already said, skyhook uses the main canopy to extract the reserve... So terminal is not an issue...
And in your original post you mentionned slider down... Slider down + terminal = ouch...

scissors beat paper, paper beat rock, rock beat wingsuit - KarlM

[ianmdrennan 2]

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But if one day your main deciedes to be really stubborn and not come out of it's bag- well, now you're set up to slow from 100+mph to 14mph in 150 feet... and send your chiropractor's kid to college shortly thereafter.

The reason the skyhook is able to deploy a reserve so quickly is because it uses the main or reserve pilot chute, whichever has the most drag, to reploy the reserve. So...terminal is not an issue, if you're at terminal your main obviously hasn't worked in which case the reserve would be deployed, like normal, via the reserve pilot chute. If you have a malfunction where the main is out it will most likely use that for reserve deployment because of the greater drag.

So at terminal the skyhook won't offer any increase in reserve deployment speed.

Blues,
Ian

Performance Designs Factory Team

[billvon 2,435]

>your reserve arranged to open 'conventionally' (300-400 feet) or to
>open lickety-split (in less than 150' or whatever).

Keep in mind that speed matters. Most reserves will open in around 100-150 feet from an ideal cutaway, but will take 200-300 feet to open at terminal. This isn't because the opening is harder during the cutaway, but because you have more speed to shed during the terminal opening.

[Tonto 1]

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But knowing one can cut away <400 ft and know...

There's one too many "knows" in that line..

t

It's the year of the Pig.

[diablopilot 2]

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Most reserves will open in around 100-150 feet from an ideal cutaway

I disagree. They might open in 100 to 150 feet from when the pilot cute leaves, but that is much different from when cutaway. TSO requirement is 300 ft from a zero airspeed release.

Watched someone do one from aproximately just over 300 feet the other day, RSL got the reserve deployment started, and they JUST BARELY got full bottom skin inflation prior to touchdown. Still broke their leg.

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