Supersonic Freefall

[expat]

"I would be lying if I said I wasn't afraid"..................One way of putting it, but good luck to him.

Matt

1000mph skydive

[Xyn_Air]

I am just not a big advocate of jumping from perfectly good aircraft, even balloons.  ;D

Still, if he does achieve supersonic free-fall, and if he does survive it, I wonder what it would feel like to break the sound barrier wearing naught but a nylon suit and crash helmet.  One would think that breaking the sound barrier in such a fashion would have dramatic effect on the human body.

Aside from that, I was not aware that you could break the cound barrier in freefall through the atmosphere (heh, I just realized how silly that sounded for a moment, as you would not have a sound barrier outside of atmosphere, but I think you get my point).  Because of air resistance, I would have thought that a person's terminal velocity would be something short of the sound barrier in freefall.

Will be interesting to see . . .

[a1]

I can just picture it now.  ;D

[Ivan]

Hasn't that been done before somewhere in the 80s by some US airforce guy?

[ozzy72]

No Ivan, back in the 60's a USAF officer did a similar jump and got close to the speed of sound (still holds the world speed record without a vehicle I believe) in order to test a special parachute that could be used by astronauts. Only did the one jump and was going like the clappers If I remember correctly it was a four-stage 'chute and each one was meant to decelerate him slightly and pull the next one out. The first two were in tatters by the time he landed and the third one was looking pretty grim as well! However it did the trick and the fourth one got him down in the Mexican desert in one piece.

[ozzy72]

A quick google later and I've found some of my memory to still be good. Appears Joe Kittinger did go supersonic

1960 -- Altitude Record and Highest Parachute Jump: Air Force Captain Joe Kittinger jumps from a balloon at 102,800 feet on August 16th and sets a world high altitude parachute jump (where he breaks the sound barrier with his body) and freefall record that still stands today.

1961 -- Current Official Altitude Record Set: Commander Malcolm Ross and Lieutenant Commander Victor A. Prather of the U.S. Navy ascend to 113,739.9 feet in 'Lee Lewis Memorial,' a polyethylene balloon. They land in the Gulf of Mexico where, with his pressure suit filling with water, and unable to stay afloat, Prather drowns.

[Hagar]

A re-enforced reinforced crash helmet will protect his ears from the thunderous sonic boom he will create as he breaks the sound barrier.

I'm not convinced he would hear his own sonic boom. :-/ I think that will be the least of his worries.

[john_uk]

It really is a leap into the unknown.

do the french not know where the earth is when you are in the sky, if its the unknown

[expat]

No Ivan, back in the 60's a USAF officer did a similar jump and got close to the speed of sound (still holds the world speed record without a vehicle I believe) in order to test a special parachute that could be used by astronauts. Only did the one jump and was going like the clappers If I remember correctly it was a four-stage 'chute and each one was meant to decelerate him slightly and pull the next one out. The first two were in tatters by the time he landed and the third one was looking pretty grim as well! However it did the trick and the fourth one got him down in the Mexican desert in one piece.

He managed 614 mph (988 km/h) or about mach.9

Matt

[Hagar]

Capt. Joseph Kittinger Jr

..... During this project, there were three high altitude jumps accomplished from a balloon-supported gondola; the first from 76,400 feet; the second from 74,700 feet 25 days later; and on Aug. 16, 1960, from 102,800 feet, the highest altitude from which man has ever jumped. It was Kittinger who did the jumping.

In freefall for four and a half minutes, Kittinger fell at speeds up to 714 mph, exceeding the speed of sound. He experienced temperatures as low as -94 degrees Fahrenheit. Kittinger opened his parachute at 18,000 feet and landed safely in the New Mexico desert after a 13 minute 45 second descent. Project Excelsior successfully proved the new parachute system, the Beaupre Multi-Stage Parachute, would solve the problem of high altitude escape by crewmen.

Air Force Link - Official Website of the USAF

[H]

A re-enforced reinforced crash helmet will protect his ears from the thunderous sonic boom he will create as he breaks the sound barrier.

I'm not convinced he would hear his own sonic boom. :-/ I think that will be the least of his worries.

It's been done before and they heard about it; you are correct about the sound being the least of worries: it was gravely aromatic, sometimes messy, and threatened to blow out the seat of their pants.

8-)

[ozzy72]

If he is going faster than the speed of sound then the sonic boom will be behind him, just the same as with aeroplanes

[expat]

Seems a little odd that 95% of websites I checked said  Kittinger's maximum was 614 mph and the Air force site adds a nice round 100 mph to that. The other 5% just quote the Air Force site :-?

Matt

[Fozzer]

..in Space, no-one can hear you Sonic Boom scream!......!

How can you create a "Sonic Boom" when there is no air in space?... ...!

..and once he reaches the resistance of the air, traveling at supersonic speeds, I think I'd rather be mowing the grass... ...!

Paul... ...!

The maximum/terminal speed of a free falling body, (Human), in air.....120 MPH......!

[H]

If he is going faster than the speed of sound then the sonic boom will be behind him, just the same as with aeroplanes

In my scenario, they weren't going until the boom which, as you indicate, was surely behind them at the moment of jetison.
If you're speaking of a sonic boom while in a free fall*, then it depends upon the direction they're facing at that moment. Otherwise, it's a matter of how soon the parachute(s) employed slowed them down enough for the sound to catch up; plus, the buffeting against the air currently around them may rather cancel additional, waning sound out if it does catch up.

*see Fozzer's entry.

8-)