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pilotdave

Cypres? Vigil? Argus? NO!

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...cause this is way better:

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Fatimah Alkhunaizi developed a skydiving suit that inflates with helium if the parachute doesn’t open. Outfitted with an accelerometer and a programmable device, the suit inflates if the skydiver drops to an altitude of 600 meters and is still traveling at a constant velocity. Once inflated with helium, the area of the skydiver’s body doubles with only a slight increase in weight, Alkhunaizi’s calculations show. The decrease in velocity and increase in drag greatly reduces the force with which the person hits the ground. “It’s automatic,” said Alkhunaizi of Khobar, Saudi Arabia. “If they faint or get a heart attack, they won’t have to worry.”



http://www.sciencenews.org/view/generic/id/43834/title/Students_present_projects_at_2009_ISEF

Dave

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Once inflated with helium, the area of the skydiver’s body doubles with only a slight increase in weight, Alkhunaizi’s calculations show. The decrease in velocity and increase in drag greatly reduces the force with which the person hits the ground.



Great! You'll only be half as dead as you would be with a normal skydiving jumpsuit!

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...cause this is way better:

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Once inflated with helium, the area of the skydiver’s body doubles with only a slight increase in weight,




Great. Doubled the area. If the drag coefficient doesn't change, instead of 120 mph, he'll hit at 1/(2^.5) times the speed, or 85 mph.

If the inflated suit provides a sort of cylinder around the jumper, doubled the area means twice the width.
Say a person is 45 cm wide. Twice the area gives a cylinder of 45 cm radius. Lets say that's how much cushion space is available infront of the jumper, and that the suit keeps the jumper somehow stable, belly to earth. (There would be less inflated space to the sides of the jumper otherwise the drag area would be more).

Ok, so he's hitting at 85 mph with a crush distance of 45 cm. Unless I mucked up the calculations, that gives something like 155 g deceleration at a very minimum if it crushes in an ideal manner.

Splat.

I think we need someone like Franz Reichelt to test the idea.

(The guy who jumped his big overcoat from the Eiffel tower to his death.)

I have neglected the buoyancy of the helium that'll only be about a cubic metre, displacing about 3 pounds of air at the maximum.


The inventor should have been able to run the same high school physics calculations to see the issues.

Perhaps he could further develop his idea into a larger air inflated structure, that uses the surrounding air to inflate it rather than a helium bottle... and call it a parachute.

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Ok, so he's hitting at 85 mph with a crush distance of 45 cm. Unless I mucked up the calculations, that gives something like 155 g deceleration at a very minimum if it crushes in an ideal manner.



I think you're in the right ballpark with those numbers, so yes, by itself, such a system is unlikely to prevent a fatality, but I have thought over the years as to whether airbagor similar technology could somehow someday help prevent double mal fatalities. There are a lot of challenges, but a little advance here, a little advance there, after 10 advances that by themselves weren't useful, we figure out useful ways to combine their effects and we come up with something workable and useful. I mean we had the mars landers break their fall from orbit to the surface of Mars by being at the centre of a large, inflatable, multi-cellular cushion.

I'm also curious as to how much this balloon suit takes away your flexibility and dexterity. I suspect that once inflated, it would reduce the movement in arms and legs, thereby making it harder for the skydiver to control body position and/or practise emergency procedures.

I'm further curious about the increase in weight that they apparently calculated. Helium is not readily extractable from the air, so presumably the helium is being carried by the jumper in a high pressure container of some kind, hence this weight is still part of the jumper's gear and their weight shouldn't increase at all. In fact, due to possible leaks in the system and their increase in buoyancy, their apparent weight in the air should go down slightly.

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It doesn't take a physicist to realize that such a device would be totally ineffective in preventing a fatality. You would need something large enough to slow down your airspeed while using the surrounding air stream to stay inflated.

We already have these devices. They are called RESERVES.

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>I mean we had the mars landers break their fall from orbit to the surface
>of Mars by being at the centre of a large, inflatable, multi-cellular
>cushion.

Well, to be fair, that is preceded by:

aerobraking to get the vehicle to a few thousand mph
a parachute to get the vehicle to a few hundred mph
a rocket system to stop the vehicle completely at about 30 feet above the ground

All that before the tether was cut and the airbags did their job.

If you did all that before you inflated the airbags, landing would be pretty easy. But most skydivers who would need this have already failed to successfully deploy either parachute.

>the helium is being carried by the jumper in a high pressure container
>of some kind, hence this weight is still part of the jumper's gear and their
>weight shouldn't increase at all.

Both helium and the pressure vessel will weigh something, and both of these will increase the weight of the jumper. Compressed helium does not displace enough air to make it buoyant.

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This idea of having airbags on a skydiver is completely ridiculous. This inventor probably thinks you can jump off a cliff with a board under your feet, and a split second before you hit the earth, step off the board to avoid death. Pre school physics at it’s best IMHO.

This reminds me of those guys who wanted to land the birdman suit with no parachute. It still hasn’t happened because it is physically impossible to transfer all vertical airspeed to horizontal airspeed without an external power source (i.e. jet engine) and then how the fuck do you slow down without flaps or a parachute when you make contact with the earth???

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a rocket system to stop the vehicle completely at about 30 feet above the ground



hey I think we have something here. Lets strap some retro boosters to a guy with a wingsuit, and use those to slow him down so he can land without a parachute. Then after the retro rockets fire, have airbags inflate around him right before making contact with the ground. Since he'll be jumping without a rig, there will be room for airbags.

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Once inflated with helium, the area of the skydiver’s body doubles with only a slight increase in weight,



egh? Where does the extra weigh come from whilst in freefall? :S

(.)Y(.)
Chivalry is not dead; it only sleeps for want of work to do. - Jerome K Jerome

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The idea should be transferred to the entire landing area rather than the jumper.

If a sensor on the jumper above the landing area detects constant velocity at a set altitude, POOF! A giant air-bag covering the whole landing area inflates. Instant bouncy-castle!

Admittedly, it might suck for those on final. :D:D:D


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The idea should be transferred to the entire landing area rather than the jumper.

If a sensor on the jumper above the landing area detects constant velocity at a set altitude, POOF! A giant air-bag covering the whole landing area inflates. Instant bouncy-castle!

Admittedly, it might suck for those on final. :D:D:D



That is the best thing I have ever heard!!!:D:D:D
Have you seen my pants?
it"s a rough life, Livin' the dream
>:)

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Why?

I predict jumpers would take turns at being the DGIT so the rest of the load would have a guaranteed soft landing.
"That formation-stuff in freefall is just fun and games but with an open parachute it's starting to sound like, you know, an extreme sport."
~mom

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It still hasn’t happened because it is physically impossible to transfer all vertical airspeed to horizontal airspeed without an external power source



Speaking of pre-school physics...:S
Do you want to have an ideagasm?

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Both helium and the pressure vessel will weigh something, and both of these will increase the weight of the jumper. Compressed helium does not displace enough air to make it buoyant.



I wasn't talking about the compressed helium in the high pressure container. I was talking about the helium that's inflating the suit. When the suit inflates, there should be a slight decrease in apparent weight, due to the buoyancy of the helium. The compressed helium and it's container must already be carried by the jumper prior to inflation, hence it is already part of the exit weight of the jumper. The original article suggests that the weight of the jumper will increase when the suit inflates, but I contend that the actual weight should not change, and the apparent weight due to buoyancy should, if anything, go down, even if only by a tiny amount. I suspect that the additional air displaced by inflation of the suit would weigh no more than a few grams at most.

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Fatimah Alkhunaizi developed a skydiving suit that inflates with helium if the parachute doesn’t open. Outfitted with an accelerometer and a programmable device, the suit inflates if the skydiver drops to an altitude of 600 meters and is still traveling at a constant velocity.



Wow, 600 meters! Hmm, that's about where my hard deck is!
"We've been looking for the enemy for some time now. We've finally found him. We're surrounded. That simplifies things." CP

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>This reminds me of those guys who wanted to land the birdman suit with no
>parachute. It still hasn’t happened because it is physically impossible to
>transfer all vertical airspeed to horizontal airspeed without an external power
>source (i.e. jet engine) . . .

Hmm. I don't have a jet engine on my Crossfire2, but I seem to be able to translate all my vertical airspeed at the beginning of my front riser turn to horizontal speed by using gravity and lift only.

Put it this way - if they can land bathtubs without power (see attachments) then can definitely land a wing!

>and then how the fuck do you slow down without flaps or a parachute when you
>make contact with the earth???

I recall a rather spectacular faceplant I made at Perris one day. Downwind landing, thought I was going slower than I was, put my feet down and - boom, I was on my belly and sliding across wet grass before I knew what was going on.

But I still stopped without flaps!

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