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Skydiver To Break Sound Barrier During Free-Fall
Hugh Pickens writes "Over fifty years ago, American Joe Kittinger made history by leaping from a balloon at 102,800 ft, and although many have sought to repeat the feat, all have failed. Now, BBC reports that Austrian extreme sportsman Felix Baumgartner will try to break the long-standing record for the highest ever parachute jump, skydiving from a balloon sent to at least 120,000 ft, and it is likely that 35 seconds into in his long free-fall of more than five minutes, he will exceed the speed of sound — the first person to do so without the aid of a machine. 'No-one really knows what that will be like,' says Baumgartner. Although challenges in the endeavor include coping with freezing temperatures and ultra-thin air, a key objective for Baumgartner will be to try to maintain a good attitude during the descent and prevent his body from going into a spin and blacking out. 'The fact is you have a lot of different airflows coming around your body; and some parts of your body are in supersonic flow and some parts are in transonic flow. What kind of reaction that creates, I can't tell you,' adds Baumgartner."
It's really going to hurt.
"The average reporter we talk to is 27 years old......They literally know nothing." - Ben Rhodes
So I guess I'm not the only one to think this guy is going to die doing this stunt.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
Just like car racing, I want to watch.
Working on new views of old physics at http://VisualPhysics.org
Am I the only one that though of the space diving scene from Star Trek 11?
If there's enough atmosphere to lift a balloon, there's enough atmosphere to transmit sound.
http://alternatives.rzero.com/
Failed?!? How can you fail that? Throw yourself self off the balloon and miss the ground?
/greger
If there's enough atmosphere to lift a balloon, there's enough atmosphere to transmit sound.
And the balloon would also be the machine he is 'not getting aid from.' he will exceed the speed of sound — the first person to do so without the aid of a machine. (from the /. story)
Home of The Suki Series
Right, a balloon is not a machine. Way to be redundant.
... will he bounce?
Meh, it's a question of technicalities. Gravity is the force that will cause him to break the sound barrier (and perhaps the thin air - lack of resistance). A machine will not be used to accelerate him. It will give him tremendous potential energy, however. Anybody want to calculate that?
he will exceed the speed of sound — the first person to do so without the aid of a machine.
He's using a machine. It's a balloon that sends him up 120,000 ft.
Test the survivability of this by using a dummy with G-force sensors (just like we see on Mythbusters).
Then, if all goes well - try the stunt.
And please, use some kind of stabilizer to make sure you don't turn into a frisbee.
I do see potential in this 'experiment' if anyone ever needs to bail out on spaceship2.
I'm going to guess that he doesn't break the sound barrier. The term "barrier" isn't entirely fanciful, as power required to go faster increases enormously as you approach it.
On the other hand, if he DOES break the sound barrier, I'm going to bet it does him some injury.
If my calculations are correct, it's 623 ergs/quartic coloumb-acre.
PE = mgh ~= 76Kg*10m/s^2*120000ft*0.3m/ft = 27,360,000Nm. This is the equivalent energy of a man the same weight traveling at about 848m/s: over twice the speed of sound. (to be fair I used the minimal mass of the average human male) I consider this significant help from technology.
@humanity: *facepalm*
Meh, it's a question of technicalities. Gravity is the force that will cause him to break the sound barrier (and perhaps the thin air - lack of resistance). A machine will not be used to accelerate him. It will give him tremendous potential energy, however. Anybody want to calculate that?
About 26 megajoule.
(If you want to check the calculation: His weight is 73 kg)
The Tao of math: The numbers you can count are not the real numbers.
More to the point, let's say he intends to go sonic at 20,000 feet. In falling 100,000 feet he'd reach a speed of 2530 ft/sec if there were no air drag. The speed of sound at that altitude is 1036 ft/sec, so he has a chance, depending on how little drag he can achieve.
As he comes down in altitude, the drag and the speed of sound both go up, so it becomes a much harder calculation. There is an abrupt drag rise right around Mach 1, so there's a significant chance he could stabilize at, say, Mach 0.98 and be unable to accelerate further.
rj
I realize that Terminal Velocity will be higher with less air density, and the speed of sound should be lower, but do they both change so much that this is actually possible?
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
I'm sure they mean the speed of sound at his particular altitude. Joe Kittenger reached 614 mph during his freefall in the 1960, which is roughly Mach 0.8 at sea level. At around 35,000 feet the speed of sound drops to around 650 mph. At higher altitudes, the speed of sound actually increases for awhile.
Isn't "terminal velocity" lower than the speed of sound?
During the fall, how far could he drift from the balloon's overhead position? A few miles? Tens of miles?
Prisencolinensinainciusol. Ol Rait!
Pretty good information about high-altitude skydiving here: Speed of a Skydiver
http://www.geoffreylandis.com
If you fart while exceeding the speed of sound, will it make a noise?
__ Someday, but not this morning, I'll finally learn to use the preview button.
Apparently you never learned about significant figures.
Strictly speaking the record will be for highest parachute jump. Assuming he's alive when he jumps he should get the record, even if he lands in several pieces.
Aside from the air friction, it's going to jolt like hell when his chute opens and he starts to decelerate.
I hope to god he's not wearing a red shirt.
The Difference between a bad golfer and a bad skydiver? one goes *Whack*... "D@mn". the other goes "D@mn"...Whack.
What can possibly go wrong?? /. memo
He will need a very pointy hat.
Ezekiel 23:20
You never do until they leave. :(
Then I guess you better make damn sure you read all your NOTAM's aye bunky?
Yeah I am a pilot.
Hey KID! Yeah you, get the fuck off my lawn!
Jeez, has no one ever heard of a back of an envelope calculation? Here, let me blow your mind: Pi = 3
@humanity: *facepalm*
Interviewer: "Is that your crash helmet?"
Jose' Jimenez: " . . . oh I hope not."
Using:
standard atmosphere http://www.desktopaero.com/stdatm.html
Mach/altitude tables http://www.aerospaceweb.org/question/atmosphere/q0112.shtml
g acceleration http://en.wikipedia.org/wiki/Terminal_velocity
and historical stuff on Col Joe.
At 35 seconds he'll have fallen from 120kft to 80kft, going 1126 ft/s. That's Mach 1 at sea level. At 80kft it's Mach 1.15, giving some room for drag error. 10 seconds later he'd cross from stratosphere to tropopause where Mach 1 is lowest, but since it's only a matter of ~6 ft/s, this just gives him room to fall farther if need be but not required. At 80kft the dynamic pressure will be around 55 lb/ft^2, so if fully loaded he weighs more than 165 lbs he'll still accelerate some, but not after the 45 second mark. If he's outfitted like Kittenger was, he'll weigh up towards 300 lbs, and would still accelerate for some time.
At 30 seconds he'll be falling at 965 ft/s, or Mach 0.98, well within the narrow transonic region of highest pressure, "max Q". This is where aircraft prior to the Bell X-1 came apart due to the buffeting of turbulence combined with the growing bow shock pressure wave.
He can do it theoretically. The altitude is just about perfect for the attempt. I'm more concerned about whether he'll be able to keep from getting the piss kicked out of him at the Mach line. Sure, it'll be slight compared to what General Chuck punched through, but he's a damn sight slighter than the X-1. On the other hand Kittenger hit Mach 0.96 around 60kft and I see no report of this effect so maybe it's not a problem.
It may still be a problem to punch through though. There's a spike in the speed/drag curve that's greater or lesser depending on the drag characteristics (coefficient of drag of cD). If his outfit will be shaped to approximate a low cD body so much the better. Since he'll require some form of protection I doubt anyone would fault him for choosing a shape to fit his flight profile.
If he kept up his falling profile he's still slow to terminal velocity for the lower altitude, around 200 MPH, slower still if he's either braking or blacked out and spinning. Lower altitude here is taken to be where he could pop the chute and stay conscious even if he lost his mask, around 20 kft. At that altitude and speed a full open would be quite a jerk, but no more than airborne troops practice, and which I'm sure he's handled previously. If he's designing his chute to be able to be opened higher/faster should he need or want to, he'll include a drogue chute with a delay before the main, to slow him gradually to safe opening speed (especially helpful if spinning).
"I may be synthetic, but I'm not stupid." -- Bishop 341-B