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-   -   Skydiver gets ready for 23 mile jump (https://www.subsim.com/radioroom/showthread.php?t=192235)

Rockstar 02-06-12 08:38 PM

Skydiver gets ready for 23 mile jump
 
He wants to drop from 120,000 feet and check parachute at 5,000 feet. Is this guy nuts or what? Current record is from 102,000 feet by USAF Col. Joe Kettinger in 1960.

http://www.dailymail.co.uk/news/arti...mile-jump.html

DRINK RED BULL :D

USS Drum 02-06-12 08:53 PM

Quote:

Originally Posted by Rockstar (Post 1834423)
DRINK RED BULL :D

It give you wings:D

August 02-06-12 10:08 PM

Airborne All The Way! :salute:

Sailor Steve 02-06-12 10:23 PM

Quote:

Originally Posted by August (Post 1834464)
Airborne All The Way! :salute:

And he will be.

At least we hope it turns out that way. :D

kiwi_2005 02-06-12 11:30 PM

That will be one hell of a rush!

Krauter 02-06-12 11:53 PM

I wonder, how do parachutes resist the "impact" of drastically slowing a man at terminal velocity when he opens his canopy?

Sailor Steve 02-07-12 01:13 AM

Quote:

Originally Posted by Krauter (Post 1834488)
I wonder, how do parachutes resist the "impact" of drastically slowing a man at terminal velocity when he opens his canopy?

Here's the perfect explanation to that question, and it ties in perfectly with the current topic. :sunny:
http://hypertextbook.com/facts/JianHuang.shtml

Tribesman 02-07-12 02:13 AM

Quote:

I wonder, how do parachutes resist the "impact" of drastically slowing a man at terminal velocity when he opens his canopy?
I wonder with the higher start and the lower deployment, how severe is that impact coing to be?

antikristuseke 02-07-12 06:42 AM

Surely he is going to use a multiple stage parachute like Kettinger did

Osmium Steele 02-07-12 08:26 AM

Quote:

Originally Posted by Tribesman (Post 1834518)
I wonder with the higher start and the lower deployment, how severe is that impact coing to be?

He'll actually slow down as he descends into the thicker atmosphere.
By the time his chute deploys, he'll be going no faster than if he'd jumped from an airplane.

The multiple drogue chutes Kittinger used were not to slow the descent, a very common misperception, but to eliminate the chance of a blackout inducing spin. He almost died during a test jump in '59 from such a spin.

From everything I've read, Baumgartner thinks he can maintain control using hands, feet and legs like any other dive, and has no intention of utilizing a drogue chute to maintain control. We'll see.

Tribesman 02-07-12 10:26 AM

Quote:

He'll actually slow down as he descends into the thicker atmosphere.
Doesn't terminal velocity mainly revolve around the principle of a lack of further acceleration?

Quote:

By the time his chute deploys, he'll be going no faster than if he'd jumped from an airplane.
What if he sticks his arm out or doesn't? either from a plane at 20,000 or from a balloon at 120,000? what if he sticks both arms out in an las vegas elvis suit?

Krauter 02-07-12 10:41 AM

Quote:

Originally Posted by Tribesman (Post 1834518)
I wonder with the higher start and the lower deployment, how severe is that impact coing to be?

Exactly what I was thinking.

Also, does the person feel any shock from the opening of a shute at such a velocity? And how does that feel/how does one deal with that?

August 02-07-12 10:48 AM

Quote:

Originally Posted by Krauter (Post 1834690)
Also, does the person feel any shock from the opening of a shute at such a velocity?

Yes but the chute harness distributes the shock over the body to lessen it's impact.

Quote:

And how does that feel/how does one deal with that?
One tries not to get ones testicles trapped between the leg strap and thigh.

Herr-Berbunch 02-07-12 10:52 AM

Can we move on from skydiving - I've done it (slightly lower than 23 miles), I can't afford to do it now but still want, want, want! :wah:

Jimbuna 02-07-12 11:52 AM

Quote:

Originally Posted by August (Post 1834697)
Yes but the chute harness distributes the shock over the body to lessen it's impact.

One tries not to get ones testicles trapped between the leg strap and thigh.

Ouch!! :o

Herr-Berbunch 02-07-12 12:04 PM

Quote:

Originally Posted by Sailor Steve (Post 1834773)
No worse than any other. It will be no difference than if he jumped at 6000 feet and pulled the cord at 5000. The drag is all the same.

Iirc you are still accelerating after 1000', but not for much.

Sailor Steve 02-07-12 12:10 PM

Quote:

Originally Posted by Tribesman (Post 1834686)
Doesn't terminal velocity mainly revolve around the principle of a lack of further acceleration?

As the air gets thicker drag increases, and the object slows down. He may be close to mach 1 at 100,000 feet, but at 5000 feet he'll be down to about 120 mph, or 200 kph.

Quote:

What if he sticks his arm out or doesn't? either from a plane at 20,000 or from a balloon at 120,000? what if he sticks both arms out in an las vegas elvis suit?
With the arms out the drag is increased. If the diver keeps his arms tucked at his sides he'll fall a little faster.

From the article I linked

Quote:

A person has a terminal velocity of about 200 mph when balled up and about 125 mph with arms and feet fully extended to catch the wind.

Osmium Steele 02-07-12 03:36 PM

Quote:

Originally Posted by Tribesman (Post 1834686)
Doesn't terminal velocity mainly revolve around the principle of a lack of further acceleration?

What if he sticks his arm out or doesn't? either from a plane at 20,000 or from a balloon at 120,000? what if he sticks both arms out in an las vegas elvis suit?

Many things determine "terminal" velocity, I'll not go into all of them here. Even wikipedia has a decent entry.

Air density has a huge effect on the speed at which an object falls.

In a vacuum, a bowling ball and a feather would drop at the same speed, not so in the atmosphere.

Now, assuming the object is not falling in a vacuum, then cross sectional area of the falling object exposed to the passing atmosphere has an effect on velocity.

A jumper diving head down with arms and legs straight will fall quite a bit faster than the same jumper spread eagle.

What is a parachute other than an object which increases your cross-sectional area against the atmosphere?

Tribesman 02-08-12 03:10 AM

Quote:

As the air gets thicker drag increases, and the object slows down
Quote:

Many things determine "terminal" velocity,
Yes, and I was wondering what the rate of decelaration due to thicker air would be and how rapidly his high velocity would be reduced, plus how far would he travel before that effect is finished and he would again be at a "terminal velocity".
@Steve, I was just pointing out that it wasn't a constant.
@Osmium, you understand why this is actually a variable...he'll be going no faster than if he'd jumped from an airplane.

Osmium Steele 02-08-12 08:27 AM

Quote:

Originally Posted by Tribesman (Post 1835209)
Yes, and I was wondering what the rate of decelaration due to thicker air would be and how rapidly his high velocity would be reduced,

Ah, Ok. That's too many maths ;), and dependent upon a whole set of variables including his own movements/actions a the time.

Even air density at a given altitude is variable based on a number of factors. Too many variables to give a solid answer, and since he will be falling, the value would be ever changing.

Let me see if I can find a chart somewhere that shows a baseline human freefall velocity at various altitudes. Should be something on the intarwebs somewhere.

Edit: Check this out. Skydiving Fall Rate

Hope that gives you the info you seek.


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