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Skydiving spheres

alternative to a parachute
  (+6, -1)
(+6, -1)
  [vote for,

A sphere made of a transparent membrane and a lightweight frame, similar to a geodesic-dome camping tent. The participant is suspended from bungee cords at the center of the sphere.

The diameter of the sphere is designed to create the required amount of aerodynamic drag and also to allow the participant to be displaced from the center by the bungee cords if the sphere impacts something hard (such as the ground).

Now, either roll this off the edge of a cliff or down a steep slope, or toss from an airplane. If rolling on the ground, the participant should be attached by a swivel (so he tends not to spin), be slightly below the exact center of the sphere, and be able to move his mass from side to side, for some semblance of steering control. And watch out for trees and traffic.

Sean Connery used something similar in an earlier James Bond film, but it wasn't transparent and he wasn't suspended.

nr6, Oct 16 2003

But the spinning is the fun part... http://www.zorb.com/
Often linked here... [RayfordSteele, Oct 04 2004, last modified Oct 21 2004]

Hot-air balloons falling http://groups.googl...etnews03%26rnum%3D1
Reports from the field [flypaper, Oct 04 2004, last modified Oct 21 2004]

Ultraball http://www.halfbakery.com/idea/Ultraball
Courtesy of [saker] - Similar [Shz, Oct 04 2004]

(?) Zorb http://www.zorb.com/thumbnails.htm
..looks like a good time.. [bpilot, Oct 04 2004, last modified Oct 21 2004]

(?) Bubble dork http://www.youtube....S98&feature=related
[doctorremulac3, Dec 05 2010]


       Q: What's to ensure that the sphere is upright when it hits the ground?
RayfordSteele, Oct 16 2003

       QQ: What does upright mean to a sphere?
Don Quixote, Oct 16 2003

       I see limitations in how much damage the frame can take ... parachutes are cool because its not such a rapid deceleration ... if you need a corpse for testing, I'll gladly let you have mine!
Letsbuildafort, Oct 16 2003

       Hmmm, From my (rusty) fluid mechanics drag force on a sphere is 6*pi*viscosity*diameter*velocity, so with viscosity of air at 1.7e-4 g/cm.s and a terminal velocity of, say 10m/s that yields 300m diameter for a 100Kg sphere + Payload. That's a BIG sphere.*   

       Spheres are really quite slippery shapes at low Reynold's numbers.   

       *...of course you could make it of something slightly elastic and pressurise it to make it bounce when it lands...
ATP, Oct 16 2003

       The link above has some empirical figures for hot-air balloons falling and reaching terminal velocity with their gas burners off. Interestingly, the range of those velocities, from 800 to 1300 ft/min, or about 9 to 15 mi/hr, is equivalent to jumping off a wall between 3 to 7.5 ft high. Googling for parachute landing speeds I found figures like 13 mi/hr. A 60,000 cu ft balloon would be about 60 ft in diameter, and of course not a sphere, but teardrop-shaped with the burner hole at the bottom.
flypaper, Oct 18 2003

       Upright = not oriented so the sphere-o-naut lands on his head.
RayfordSteele, Oct 18 2003

       I like the idea of being in freefall with no wind, dressed in jeans and a t-shirt. Or naked. No, maybe jeans and a t-shirt.
wagster, Aug 06 2004

       Better to make the sphere inflatable rather than framed, that way the structure won't break and you have a giant airbag protecting you. The big problem is that you would need a biiig sphere. I seem to recall an old style jumping parachute is about 40' or so in diameter, and that would have more drag than a sphere. You would need an even larger sphere to get a similar falling speed, although you would have the sphere absorbing the impact rather than your knees.
macrumpton, Aug 06 2004

       fill the big elastic sphere with helium, suspend the sphere-o-naut in his or her own air-filled sphere, attached by bunjees, and you could get a lot more bounce. i'm thinking slow-mo, like men jumping on the moon.
wabisabi, Aug 07 2004

       I saw something similar in a Jackie Chan movie. The intro shows him on a powered parachute, and then he gets to a cliff, lands the chute and discards, and inflates this gigantic clear ball. The ball itself was constructed in cells, like a soccer ball(football). Jackie wiggled inside, and rolled himself down a steep rocky mountain. I hate Jackie sometimes. He gets to have all the fun.
destructionism, Aug 07 2004

       See link for the thing Jackie was rolling in.   

       BTW, anyone know which in which movie Jackie jumped *into* a stepladder?
bpilot, Aug 07 2004

       //if the sphere impacts something hard (such as the ground)//   

       What are the alternatives?
English Bob, Aug 09 2004

       Float away, and never be seen again.
destructionism, Aug 09 2004

       [bpilot] Shanghai knights.   

       [destructionism]: Armour of God
spacemoggy, Aug 09 2004

       [Bpilot] First Strike.
GutPunchLullabies, Aug 09 2004

       Sounds like fun, but I'll keep my parachute. It glides a bit better than a sphere, and the unobstructed view is great. It would take almost fifteen minutes to fall 13,000 feet at a "safe" velocity for impact (~10 mph), during which time you'd be subject to the winds aloft, and you'd be unable to control your landing point.
Freefall, Aug 09 2004

       [GPL], that's it! Thanks. Gotta find a copy.
bpilot, Aug 09 2004

       [Freefall]: Yeah, but the sheer terror alone, wondering if you're going to land in that fluffy field or the nearby foundry, would be pretty cool.
shapu, Aug 09 2004

       I've had experiences where the winds were so far from what was measured only twenty minutes before that I wasn't sure if I was going to make it back to the drop zone, was going to come up short in the lake, come up shorter in the power switching facility, or if I should turn around and land in an off-site field.   

       (I chose the field. the long walk back was infintely preferable to a death by electrocution))   

       The wonder was most assuredly not fun.
Freefall, Aug 09 2004

       Re: landing on that foundry, etc. Drop the skydiving sphere offshore for collection by boat. This pastime is getting a little expensive, though.
bpilot, Aug 10 2004

       Drift seems to be a big problem in this idea. If the sphere was stable enough, and strong enough, control surfaces could be added facing downward, into the relative wind. Then, with your controls on the inside, you could angle them both slightly forward to go forward, backwards, and opposite to roll the sphere to a different heading.   

       Another problem is getting down at all if you catch a good thermal. You can stall a parachute and descend rapidly, but you can't stall a helium sphere.
destructionism, Aug 10 2004

       Shirley the passenger should be suspended in a gyroscope rather than bungee cords. This would allow the passenger to control their orientation within the sphere. To accomplish this, the frame of the gyroscope would need to be rigid, which would be difficult for a sphere that deforms as it bounces. To accomplish that, we need to introduce the concept of having an inner (rigid) and outer (deformable) sphere.   

       Fortunately, this will be impractical to implement. We need to add a large network of dampers to absorb the impact between the inner and outer spheres. Assuming the sphere makes contact with the ground, the dampers toward the ground would absorb energy on compression, and the dampers towards the sky would absorb energy upon extension. [+]
ed, Jul 02 2008

       If the devices consists of two concentic spheres, joined by numerous bungee cords, then the gap could be rapidly filled by a cool-burn pyrotechnic gas generator.   

       This would effectively be a "parachute" that could be used by a completely untrained person. Climb in, zip up outer and inner ports, jump. Static line triggers gas generator; float slowly down.   

       Hot air balloon fabric would be fine - it doesn't need to be truly airtight, the pressure difference will be small.   

       On landing, both the bungees and the pressure within the double wall will act to absorb inpact energy, and because of the low terminal velocity that impact energy will be modest.
8th of 7, Dec 05 2010

       I liked this and was going to suggest 2 concentric spheres, the central one being where the person is and the first being a shock absorber when it hits the ground. 8 beat me to it.   

       I was thinking it would be all one material but joined the way soap bubbles link together when somebody puts on one of those soap bubble shows and blows smoke into the center one.   

       That's where the person would be.   

       Neat idea but not super practical.
doctorremulac3, Dec 05 2010

       Contact velocity could be significantly higher than a traditional parachute, since the sphere collapsing under the passenger would absorb energy that is presently only absorbed by the parachutists legs.
MechE, Dec 06 2010

       Depends on the size of the outside ball relative to the weight of the guy inside.   

       But I'd think it would have to be pretty big. A parachute scoops the air and lets a little bit escape out the top to retain it's shape. The ball would just be pure aerodynamic drag. It's also a lot more material than a chute which would add to the weight.   

       Also, if it's got enough area to slow a passenger's vertical decent, that same area would be very susceptible to cross winds and this thing might fly horizontally a lot more than a chute.
doctorremulac3, Dec 06 2010

       Over the sea, it would float a lot better than a 'chute. Could be adapted into a liferaft.
8th of 7, Mar 24 2011


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