High-G Auto Cutaway Mechanism

[tso-d_chris 0]

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How about enough weight built into the cutaway pillow, that it will overcome the velcro forces at a certain g loading. It should be a simple math equation.

I thought about that after Chris Martin's accident. I don't know if it would withstand opening shock. If it were attached at the lower leg, the G-forces from a spinning canopy would be much higher, and a lighter handle could be used, which would be more likely to make it through opening shock.

[rsibbald 0]

Roger - cheers - they look like they have a good chance of standing up to what I want.

Spizz - unfortunately, velcro is almost impossible to shear when the pull force is at the wrong angle.

Matt - I'll let you know when I have video I wouldn't want Jeb to beat me to it now.....

[mr2mk1g 10]

hehe fair enough.

[tso-d_chris 0]

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velcro is almost impossible to shear when the pull force is at the wrong angle.

I suspect that the force required to shear hook/pile contact would be fairly consistant, wear notwithstanding. Velcro does wear out MUCH faster when seperated in such a manner, though.

Remember, forces change with different scenarios. A solution that would work well with a spinning canopy would not necessarily work with a spinning board. A third scenario is likely to be different than either of those two.

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[Spizzzarko 0]

Do you have a line on someone who makes the Deja Blue weight belts?

[billbooth 10]

I think you guys need a variation of one of my first inventions..."The Pucker Factor AAD". It's quite simply really. First you tie a lead sinker to a long piece of line, and swallow it. When it comes out the other end, you attach it to the small end of a solid cone. You then cram the cone us your ass, and tie the other end of the cord (which is hanging still hanging out of your mouth) to your reserve ripcord handle. If you get scared enough, the pucker factor will squeeze out the cone and activate your reserve.

No batteries or pyrotechnics, and its self-calibrating. Whadda ya think?

[crazydiver 0]

Hell of an idea. Only Bill Booth could come up with that. Better start applying for a patent.

Cheers,
Travis

[BlindBrick 0]

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How about enough weight built into the cutaway pillow, that it will overcome the velcro forces at a certain g loading. It should be a simple math equation.

I'd hate to be the poor SOB that landed on.

-Blind

"If you end up in an alligator's jaws, naked, you probably did something to deserve it."

[tso-d_chris 0]

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No batteries or pyrotechnics, and its self-calibrating. Whadda ya think?

Uh- yeah- sure. Can I borrow a jumpsuit, Bill?

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[RogerRamjet 0]

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Roger - cheers - they look like they have a good chance of standing up to what I want.

Good deal. I'm hoping the board or whatever it is has it's own deceleration device for after the cutaway?

As for cutting the thing away intentionally, you may have to rig something to release the pin tension manually. Water-skiers using the system typically take their feet out of the boots leaving the system attached. Should be interesting....

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Roger "Ramjet" Clark
FB# 271, SCR 3245, SCS 1519

[phoenixlpr 0]

I do agree. I won`t trust my life for the next gadget. Anyway even a AAD misfire can cause trouble with those spoon-up devices.

Skydiving is optional, landing is not....

[dorbie 0]

In an earlier thread I suggested a cutaway system for intentional cutaway jumps only, not something you'd want to land or get low with. The proposal was to route the cutaway cables down and around one foot.

If routed correctly the jumper would have to actively maintain flexion in the leg to prevent cutaway. Actively straightening the leg or G-loc would result in the leg straightening and cutting away anyway, although the intent is that under high G loading it would be easy to straighten the leg before loss of consciousness.

The advantage is you're not relying on some delicate ballance of forces of a weight vs velcro (or more sophisticated equivalent). You rely on active application of force to prevent cutaway and have total control unless you cannot hold your leg in a flex in which case you would automatically chop, particularly in a high G situation.

A modification would be to be able to disconnect the foot routed cable while above the hard deck, but I'm not really advocating that, this was purely an idea for experimental tertiary rig jumps.

[JohnGraham 0]

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An automatic device to cutaway my main has to be about the scariest device I can think of.

An unintentional AAD fire sucks bad enough. An unintentional automatic cutaway at, say....200' will pretty much ruin your day.

Oh, such a device would blatantly have to have a way of turning it off once you were under canopy, as well as turning itself off below a certain height (much like a CYPRES turns itself off below 150ft). This could either be via a button or by actually disconnecting a part of the system, so there's no way it can accidentally cut you away once you're open and not being spun-round.


Ross I'll be happy to do any number-crunching you need, (part of the math project i just handed in was on the 3-ring system not that complicated to model really) so long as you tell me what this is all about... or are you just after a way to automatically chop a SS board???

[Kris 0]

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Oh, such a device would blatantly have to have a way of turning it off once you were under canopy, as well as turning itself off below a certain height (much like a CYPRES turns itself off below 150ft). This could either be via a button or by actually disconnecting a part of the system, so there's no way it can accidentally cut you away once you're open and not being spun-round.


Ross I'll be happy to do any number-crunching you need, (part of the math project i just handed in was on the 3-ring system not that complicated to model really) so long as you tell me what this is all about... or are you just after a way to automatically chop a SS board???

Between jumping a Stiletto, looking for traffic, and, on occasion, having to do housekeeping with my birdman suit my answer would be No Thanks.

I already have enough to do in the air.

Sky, Muff Bro, Rodriguez Bro, and
Bastion of Purity and Innocence!™

[dorbie 0]

That's one of the reasons I saw this as being exclusively for intentional cutaway jumps under experimental canopies.

I just see this as an option for test pilots flying experimental canopies. Definitely not something anyone would attempt to land or even get low with.

[JohnGraham 0]

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That's one of the reasons I saw this as being exclusively for intentional cutaway jumps under experimental canopies.

I just see this as an option for test pilots flying experimental canopies. Definitely not something anyone would attempt to land or even get low with.

Ditto - it would not be something you would "normally" have on your rig, unless I suppose if you had a rig that you only ever opened high on and thought it was worth the extra time to turn off/use, but that would be rare.

[hufggfg 0]

During this "stunt" you're planning, would the problem g-force definately be in a certain direction, or would it need to work regardless of direction?

[rsibbald 0]

If something goes wrong, it could be in any direction, any axis, probably varying the plane of rotation very quickly.

[rsibbald 0]

Unfortunately actively using leg muscle sto prevent a cutaway would result in tiring too quickly for the intended duration. Plus it eliminates multiple other problems if legs are locked straight....

[rsibbald 0]

Yep, I'll arrange a drogue for the the attached board which will deploy on cutaway and won't be trying this near populated areas.

I am leaning towards the use of the waterski-mounts as the automatic method and a normal skysurf cutaway as the manual method.

Roger - if one foot released, and the board went into a powerful spinning motion, will the other foot mount release as effectively, or will it twist my foot off?

i.e. does the force have to be pulling the board down away from your foot for them to work correctly?

[JohnGraham 0]

You want to take a surf-board up with you Ross, don't you? Don't you?

[rsibbald 0]

Nope, too big

[RogerRamjet 0]

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Yep, I'll arrange a drogue for the the attached board which will deploy on cutaway and won't be trying this near populated areas.

I am leaning towards the use of the waterski-mounts as the automatic method and a normal skysurf cutaway as the manual method.

Roger - if one foot released, and the board went into a powerful spinning motion, will the other foot mount release as effectively, or will it twist my foot off?

i.e. does the force have to be pulling the board down away from your foot for them to work correctly?

The system I sent you the link for has BOTH boots mounted to the same release, so if something releases, both boots go as a unit. If you somehow get a foot out of one of the boots, the system will still release from the ski (err board) in any direction except directly at the board, so your remaining foot should not be twisted off.

You will be using a system designed specifically for water-skiing for another purpose, so I would urge extensive ground testing of release pressures for various angles of separation before testing in the air.

These releases actually work best to the sides as that is the most common "get off" for a slalom water-skier. They will release straight up as well, but I believe it takes a bit more pressure. That may well work to your advantage if you are forseeing a spinning issue with you building g's away from the board (or whatever it is) as you could tune the release pressure to just above what you determine to be normal (non out of control spin mode).

-----------------------
Roger "Ramjet" Clark
FB# 271, SCR 3245, SCS 1519

[rsibbald 0]

Bill - I hate to be the one to point out a design flaw in one of your great ideas - but if you were using a Pucker Factor AAD and went to the curry house the night before, you might be at risk of a premature reserve deployment the next day

[rsibbald 0]

Roger - Sounds good, I'll have to get myself to the water park this weekend and inspect some gear.

Many thanks for the info!