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G-Force question

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I'm not exactly sure....

I'm being told by the manufacturer of my pacemaker that their concern with skydiving is that the g-forces could move the device.

On my tandem I didn't feel any kind of pulling like on an amusement park ride.

Just wondering I guess - I have a feeling I'll be getting horribly bad news in the next few days.

Jennifer

who feels like she's going to start crying now...
Arianna Frances

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Umm...they go up a split second when the chute catches ya, and if something malfunctions and you get locked in a spin, you'll pull a few. Beyond that, they're negligble. Roller coasters drop you, and while still accelerating pull up suddenly, and then while going up, will crest hills and go down again(give you negative g's)and make high speed tight turns.

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>I'm being told by the manufacturer of my pacemaker that their
>concern with skydiving is that the g-forces could move the device.

The place to worry is during opening. A normal opening is 1.5 to 2 G's, a soft opening is barely over 1G. A hard opening can hit 10 G's. Unfortunately, there's no way to guarantee you won't experience a hard opening; even the softest opening canopies have "rouge" openings sometimes that can really slam you.

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Humans start blacking out anywhere over 4 Gs(that number gets higher for different people, fighter pilots for example, have a higher tolerance)rollercoasters probably hang around the 4 G or less, maybe occasionaly poking up to 5 or so for a second. Sustained 4-5Gs will black you out pretty quick, but roller coasters don't sustain them. If you have a hard opening, you'll only be feeling those Gs for an INSTANT, but think about it. 120-15 in under a second. Yowch

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I'll be presenting information to my doctor when I return from vacation next week.

I want him to be very informed and not make a decision based on bias - which is a normal thing for anyone, not just doctors.

The two things he'll be worried about are device, lead dislogment and pressure on the device from straps.

Where can I find information that would explain how skydiving would affect these things - I'll search far and wide for the information. I don't want anything to keep me from this - let alone something I didn't ask for in the first place...

thanks for everyones help.

Jennifer
Arianna Frances

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Just a thought, but you may want to ask one of the container manufacturers if they have any data on this. They are the ones that have to build the harnesses to take the stresses involved in deployment and turns, etc.

You could try, RWS, Mirage, Sunrise Rigging, etc. They might give you somewhat better of an idea of the forces expected durring a skydive.
~D
Where troubles melt like lemon drops Away above the chimney tops That's where you'll find me.
Swooping is taking one last poke at the bear before escaping it's cave - davelepka

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>can I ask what 10 Gs would compare to...

In New Jersey, roller coasters are limited to 5.6 G's for safety reasons. Fighter pilots can endure 8 G's for a short time while staying conscious. G-forces alone are a poor indicator of stress, though. You can generate almost 10 G's for a very short time by plopping down on a wooden bench. A true 10G opening in freefall lasts a little less than a second, so it's worse than the bench-sitting event but not as bad as a pilot pulling 8 G's for ten seconds.

We perceive hard openings as sort of an impact, as if you'd jumped off an 8 foot ledge. You may ask about it in that way; see what impacts are contraindicated (i.e. if you have to be careful about playing rugby or jumping in place.)

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>Just a thought, but you may want to ask one of the container
>manufacturers if they have any data on this.

Talked to Sandy Reid a bit. Harnesses can generally take 4000 lbs with no problems; this corresponds to a 20G opening, which most people would consider very painful. Above 6000 lbs there begins to be a good chance of rig failure, and thus questions of whether a pacemaker pulls free become sort of moot. Generally such loads are not seen unless you have a big guy who deploys his reserve while in a head-down or something.

Sandy recommended talking to Jim Crouch at USPA; they may have some historical info on pacemaker use in skydiving.

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Cool site....I wonder what kind of G's are pulled in a good sprial( the kind where every 360 has your legs begging you to stop it...because the leg straps are becoming part of you)?

With a concern about how your pacemaker will handle G forces....you prob wont be doing them mailin...but now I'm curious:)


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Quote

Humans start blacking out anywhere over 4 Gs(that number gets higher for different people, fighter pilots for example, have a higher tolerance)rollercoasters probably hang around the 4 G or less, maybe occasionaly poking up to 5 or so for a second. Sustained 4-5Gs will black you out pretty quick, but roller coasters don't sustain them. If you have a hard opening, you'll only be feeling those Gs for an INSTANT, but think about it. 120-15 in under a second. Yowch



The amount of G's a human can take depends on the person and time. Loads up to 18 G's can be taken if the duration is short, or as little as 4 G's will put you out if the duration is several sec. I have taken 14/15 on several occasions and only grayed out once.
My idea of a fair fight is clubbing baby seals

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I've never had a really hard opening before, so I have no idea how to fathom this.

Anyone who has had a 10G opening, describe the what/where/why/how's of it, because my wildest imagination can't come up with something that would make an opening pull 10Gs.

Thanks

-Kramer

The FAKE KRAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMER!!!!!!!!!

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