Skydiver Felix Baumgartner seeks to break sound barrier

http://news.bbc.co.uk/2/hi/8475288.stm

by hnal943 • 16 years ago

15 17 16 years ago

news.bbc.co.uk

diego2• 16 years ago

"It is likely that in his long freefall of more than five minutes, he will exceed the speed of sound - the first person to do so without the aid of a machine."

If he can reach 120k feet, I bet there is a machine involved in the process. Why not just say he's the first person to do it through freefall?

sp3322• 16 years ago

They mean his acceleration will be without the aid of a machine.

diego2• 16 years ago

Again, it's not true. He's just converting the potential energy stored with the aid of a machine into kinetic energy.

tkahn6• 16 years ago

From a quick Google search, the terminal velocity of a human being is roughly 120 mph. The speed of sound (at sea level) is 761 mph.

How is this feat possible?

smitjel• 16 years ago

My thoughts exactly...I'm sure he'll be carrying extra weight but I still don't see how this is possible given a certain terminal velocity, like you said.

*Edit...wikipedia says current world record is 614 mph set by Joseph Kittinger. He used the head down method in high altitude, less dense air. That's still not supersonic though.

hnal943• 16 years ago

Kittinger wasn't as high up, the extra height should give Baumgartner more time to build speed.

zck2• 16 years ago

As mentioned in the article, Kittinger "only" jumped from 102,800 feet. Baumgartner will jump from 120,000. Also, Kittinger was in a "rocking chair" position, not head-down. (http://en.wikipedia.org/wiki/Joseph_Kittinger)

zck2• 16 years ago

The air's much thinner up there (99% of the atmosphere is below 20 miles up: http://www.albany.edu/faculty/rgk/atm101/structur.htm). Also important -- the 120 mph seems to be in a spreadeagle position.

j-g-faustus• 16 years ago

Terminal velocity depends on the drag/friction from the air, at higher altitudes the air is thinner. So less drag and higher terminal velocity.

The current world record is ~600 mph. http://en.wikipedia.org/wiki/Terminal_velocity#Examples

pvg• 16 years ago

The terminal velocity is much higher in this case because the skydiver is assuming a position that minimizes drag and the air is much less dense at the altitudes in question. Additionally, the lower temperature reduces the speed of sound in a smaller but still significant degree.

neurotech1• 16 years ago

The terminal velocity in the stratosphere is significantly higher than at sea level, and the speed of sound is lower, at around 670 mph. Joeseph Kittingers' record was 614 mph, which is not that far off the sound barrier.

Pilots have ejected out at Mach 3 from a SR-71 http://www.alexisparkinn.com/sr-71_break-up.htm

In that accident, the pilot ejected without major injury, but the co-pilot was killed.

InclinedPlane• 16 years ago

Excellent article. Note though that the pilot did not technically eject, his ejection seat was ripped out of the disintegrating plane intact by aerodynamic forces. Though the experience is probably applicable to the case where a pilot were to intentionally eject at Mach 3.

storborg• 16 years ago

In addition to the reduced air density at altitude (as others have mentioned), body position, weight, and clothing also have a lot to do with terminal velocity. A light person wearing baggy clothes in a belly-down position might fall at only 90 mph, whereas a heavy person wearing skin-tight clothes in a head-down position could fall at 170 mph. (speeds given at lower altitudes, close to the ground)

mrduncan• 16 years ago

He's being sponsored by Red Bull (http://www.redbullstratos.com/). Their marketing video is actually really cool, it includes plenty of footage of Kittinger.

http://www.youtube.com/watch?v=PyGmTV0q2kY (make sure you switch to HD)

sp3322• 16 years ago

I used to think that Red Bull just put their logo on cool stunts, but it turns out that they have a really competent team of engineers and fabricators to pull this off. In fact, Joeseph Kittinger, who holds the record currently, said they were the first crew to approach him that sounded like they could do this without killing someone (since 1960!), so he's actually working with them on this.

jluxenberg• 16 years ago

More details on the suit in this article / video: http://www.pureskydive.com/2010/03/red-bull-video-reveals-ne...

Skydiver Felix Baumgartner seeks to break sound barrier

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