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Supersonic Skydiver

835 Views 27 Replies 10 Participants Last post by  Soopahmahn
Skydiver preparing for 120,000-foot supersonic fall -

Anyone want to speculate on the physical effects of breaking the sound barrier on a human? I'm not entirely sure I understand what happens - the sound waves of your passing are in essence building up behind your axis of flight right? So isn't it dangerous to come back from supersonic? Depending on the altitude at which crossing that threshold occurs, there would be more or less pressure built up behind you, so I could see that wreaking havoc with his parachute or maybe tossing him around a bit extra?

Kudos to Red Bull too :yesway:
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I want to see the math on him hitting Mach 1 in free fall. Jumping 120,000 feet is nuts and all but I'm not sure the breaking the sound barrier claims might be hyperbole.
1893 ft/s = 1290 mph. That's almost Mach 2 if he hits it. :eek:
What numbers are you plugging in? I'm not sure how to guesstimate his surface area, drag coefficent are the medium density. :lol:
Here's an interesting read on the guy who holds the record that is trying to be broken.

Speed of a Skydiver (Terminal Velocity)

On 16 August 1960, US Air Force Captain Joseph Kittinger entered the record books when he stepped from the gondola of a helium balloon floating at an altitude of 31,330 m (102,800 feet) and took the longest skydive in history. As of the writing of this supplement 39 years later, his record remains unbroken.

The air is so thin at this altitude that it would make for a moderate laboratory vacuum on the surface of the earth. With little atmosphere, the sky is essentially black and the sun's radiation is unusually intense despite polar temperatures.

Sitting in my gondola, which gently twisted with the balloon's slow turnings, I had begun to sweat lightly, though the temperature read 36 degrees below zero Fahrenheit. Sunlight burned in on me under the edge of an aluminized antiglare curtain and through the gondola's open door.

The density of air at 30 km is roughly 1.5 % that at sea level and thus drag is essentially negligible.

No wind whistles or billows my clothing. I have absolutely no sensation of the increasing speed with which I fall. [The clouds] rushed up so chillingly that I had to remind myself they were vapor and not solid.

This is not true for skydivers at ordinary altitudes, which is why they reach terminal velocity and cease to accelerate.

According to Captain Kittinger's 1960 report in National Geographic, he was in free fall from 102,800 to 96,000 feet and then experienced no noticeable change in acceleration for an additional 6,000 feet despite having deployed his stabilization chute. This gave him an unprecedented 3900 m (12,800 feet) over which to accelerate. At such extreme altitudes the acceleration due to gravity is not the standard 9.81 m/s2, but the slightly lower value of 9.72 m/s2. Using these numbers, it is possible to calculate the maximum theoretical velocity experienced during this record-setting jump. The result is amazingly close to the value recorded in National Geographic.

As one would expect the actual value is slightly less than the theoretical value. This agrees with the notion of a small, but still non-zero, amount of drag.

At nine-tenths the speed of sound, Captain Kittinger also holds the record for the greatest speed attained by a human without the use of an engine. The standard value of the speed of sound in air at 31,000 m is 300 m/s (670 mph).
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