Breaking the sound barrier. Without a plane.

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CLite

Golden Member
Dec 6, 2005
1,726
7
76
An Al frame with a Kelvar type material that's air tight might hold up. Might not be possible with materials we have today though, just an idea.

Let's say it was basically the size of your typical monitor (24" diameter), it'd have to withstand 27,000 lb's of crushing force (12)^2*PI*4*14.7.

It'd have a bouyant force of 4/3*PI*12^2 * 0.007492/12^3 = 0.026 lb's

So something weighing 0.026 lb's would have to withstand a load of 27,000 lb's. Exotic materials or no, such a device would never work. Keep in mind most "strength-to-weight" numbers are based on tensile strength which in a design like this would be orders of magnitude higher than the margin on buckling failure that this device would experience (if I pull on my straw it resists, but if I push my straw together it "buckles" very easily).
 

sdifox

No Lifer
Sep 30, 2005
100,483
17,953
126
Let's say it was basically the size of your typical monitor (24" diameter), it'd have to withstand 27,000 lb's of crushing force (12)^2*PI*4*14.7.

It'd have a bouyant force of 4/3*PI*12^2 * 0.007492/12^3 = 0.026 lb's

So something weighing 0.026 lb's would have to withstand a load of 27,000 lb's. Exotic materials or no, such a device would never work. Keep in mind most "strength-to-weight" numbers are based on tensile strength which in a design like this would be orders of magnitude higher than the margin on buckling failure that this device would experience (if I pull on my straw it resists, but if I push my straw together it "buckles" very easily).


If we can harness nanotubes, it might be possible.
 

CLite

Golden Member
Dec 6, 2005
1,726
7
76
Nanotubes have incredible strength to weight ratio, but again in tension (being pulled) not being "crushed". I suppose a light-weight interior web could be developed that decreases all the critical buckling lengths inside the sphere to negligible amounts, but I'm extremely skeptical.

Anyways, a vacuum is only around 10% more bouyant than helium or hydrogen so we would be attempting to build something orders of magnitude stronger to gain almost no benefit.
 

sdifox

No Lifer
Sep 30, 2005
100,483
17,953
126
Nanotubes have incredible strength to weight ratio, but again in tension (being pulled) not being "crushed". I suppose a light-weight interior web could be developed that decreases all the critical buckling lengths inside the sphere to negligible amounts, but I'm extremely skeptical.

Anyways, a vacuum is only around 10% more bouyant than helium or hydrogen so we would be attempting to build something orders of magnitude stronger to gain almost no benefit.



What I am thinking is tent like setup, with spines to provide structure. Dyson's Sphere might work too. This is just idle thought anyway :p
 

JTsyo

Lifer
Nov 18, 2007
12,035
1,134
126
Let's say it was basically the size of your typical monitor (24" diameter), it'd have to withstand 27,000 lb's of crushing force (12)^2*PI*4*14.7.

It'd have a bouyant force of 4/3*PI*12^2 * 0.007492/12^3 = 0.026 lb's

So something weighing 0.026 lb's would have to withstand a load of 27,000 lb's. Exotic materials or no, such a device would never work. Keep in mind most "strength-to-weight" numbers are based on tensile strength which in a design like this would be orders of magnitude higher than the margin on buckling failure that this device would experience (if I pull on my straw it resists, but if I push my straw together it "buckles" very easily).

4/3*PI*r^3 for volume so 0.320 lbs, still light.
For the force on it, you might want cross sectional area instead of total area. Consider a cube. The pressure on each 2 sides try to compress it in each direction and the other 4 doesn't contribute.
Pi*r^2*14.7 = 6646.752 lb.
 

JTsyo

Lifer
Nov 18, 2007
12,035
1,134
126
Nanotubes have incredible strength to weight ratio, but again in tension (being pulled) not being "crushed". I suppose a light-weight interior web could be developed that decreases all the critical buckling lengths inside the sphere to negligible amounts, but I'm extremely skeptical.

Anyways, a vacuum is only around 10% more bouyant than helium or hydrogen so we would be attempting to build something orders of magnitude stronger to gain almost no benefit.

but if helium is expensive and hydrogen is explosive it might be worthwhile.
 

Jeffg010

Diamond Member
Feb 22, 2008
3,435
1
0
How is this guy surviving the air pressure lack of oxygen. I just watched that vid of Kittinger that just nuts. I still don't know how that guy is still alive. What about divers that have to breath out so there lungs don't explode. Same thing going to happen when this guys jumps?
 

Ns1

No Lifer
Jun 17, 2001
55,420
1,600
126
How is this guy surviving the air pressure lack of oxygen. I just watched that vid of Kittinger that just nuts. I still don't know how that guy is still alive. What about divers that have to breath out so there lungs don't explode. Same thing going to happen when this guys jumps?

he's in a suit...

Felix Baumgartner's full-pressure suit and helmet are his personal life support system. Once Felix jumps, this system will be his only protection until he reaches the safety of the lower atmosphere.

FULL-PRESSURE SUIT

Full-pressure space suits have never been qualified for the kind of controlled freefall that Felix must execute to return safely to earth. Proof that a full-pressure suit could provide protection from such a bailout will be valuable for aerospace safety researchers.

- The suit is designed to provide protection from temperatures of +100°F to -90°F.

- When pressurized to 3.5 pounds per square inch (roughly equivalent to the atmospheric pressure at 35,000 feet), the suit can help to avert symptoms of decompression sickness (the "bends").

- Above about 62,000 feet, the liquid in Felix's tissues could turn to gas and expand dangerously, a condition called ebullism, but the suit will maintain pressure around his body to prevent such expansion.

- Felix's suit was modeled on suits worn by pilots of high-altitude reconnaissance aircraft. However it has been custom made to his measurements and modified with new enhancements.

- Skydivers need to be able to use body positions and visual cues, but an inflated pressure suit and its helmet limit range of motion and peripheral vision. With modifications, including mirrors and added mobility, the Red Bull Stratos suit may serve as the prototype for the next-generation full-pressure suit.

- The exterior of the suit is made of a material that is both fire retardant and an insulator against extreme cold.

- A "controller" is the "brain" of the suit. Only the size of a hockey puck, it's an extremely reliable mechanism for maintaining pressure automatically at various altitudes.

- A vent hose fitting will keep the suit ventilated with warm or cool air in the capsule.During the long ascent, warm air will help to keep Felix from becoming dangerously "cold soaked," while cool air can help to avert perspiration that can fog the visor.

- The suit attaches to the helmet with a rotating, locking neck ring, and the gloves use a similar rotating and locking device. These types of rings operate with ease under pressurized conditions.

PRESSURE HELMET AND VISOR

- The helmet shell is molded from composite materials, which help to keep its weight low (about 8 pounds), yet are strong and resistant to impact.

- The visor is distortion free in the critical vision area because visual cues are important both in the capsule and for orientation during descent and landing.

- The helmet's oxygen regulator will provide Felix with 100 percent oxygen to breathe from various sources (a liquefied oxygen source on the ground before launch, from the capsule's liquefied system when he's onboard, and from a pair of high-pressure gaseous oxygen cylinders during the freefall descent).

- An independently operated sunshade is fitted over the visor so that Felix can adjust it to his needs.

- The visor has an integrated heating circuit to prevent fogging and icing.

- A number of redundant (backup) systems are incorporated into the helmet/visor. For example, the visor is equipped with a mechanism that requires two separate coordinated actions to unlock; this safeguard is designed to prevent accidental opening that would depressurize the suit.

- The helmet isequipped with a microphone and earphones for contact with Mission Control. The helmet drinking port will enable Felix to stay hydrated yet maintains a tight seal.

ADDITIONAL INFORMATION

How many pressure suits have been made for the Red Bull Stratos mission?

One prototype and two production suits.

Who made the Red Bull Stratos full-pressure suit?

David Clark Company produced the suit. David Clark Company has pioneered air and space crew protective equipment design, development, test, evaluation and production since 1941, with products ranging from anti-G suits to space suits and ancillary equipment.

Additional information can be found at www.davidclark.com.

Who else is involved in fitting, testing and producing the Red Bull Stratos full-pressure suit?

Red Bull Stratos team members involved with the capsule, parachutes, cameras and communications collaborate closely to make sure that their systems interface optimally with the suit. Taking the lead in coordinating them is the Red Bull Stratos life support engineer, Mike Todd.

For almost 30 years, Mike worked in the High Altitude Life Support and Pressure Suit Division of Lockheed's "Skunk Works," and he also fitted pressure suits for Steve Fossett's record-breaking Perlan glider project.

Riedel Communications provides the flight communications radios that Felix wears, as well as those in the capsule.

http://www.redbullstratos.com/technology/pressure-suit-and-helmet/
 

mizzou

Diamond Member
Jan 2, 2008
9,734
54
91
So if he is traveling faster than sound....what does he hear on his way down?
 

sdifox

No Lifer
Sep 30, 2005
100,483
17,953
126
He's done it

http://www.theglobeandmail.com/news...d-barrier-with-record-skydive/article4611689/

Austrian daredevil breaks sound barrier with record skydive

Michael Thurston
Published Sunday, Oct. 14, 2012 10:17AM EDT
Last updated Sunday, Oct. 14, 2012 04:04PM EDT
Austrian daredevil Felix Baumgartner became the first man to break the sound barrier in a record-shattering freefall jump from the edge of space Sunday, organizers said.
The 43-year-old jumped from a capsule more than 39 kilometers above the Earth, reaching a speed of 1,136 kilometres per hour before opening his red and white parachute and floating down to the New Mexico desert.
Mission control erupted in cheers as Mr. Baumgartner made a near-perfect jump from the capsule hoisted aloft by a giant helium-filled balloon to an altitude of 39,044 meters, even higher than expected.
“I think 20 tonnes have fallen from my shoulders. I prepared for this for seven years,” Mr. Baumgartner told German-language ServusTV in Austria, in his first interview after the leap.
Referring to a helmet problem that nearly forced him to abort at the last minute, Mr. Baumgartner said: “Even on a day like this when you start so well, then there’s a little glitch.
”And you think you’ll have to abort -- what if you’ve prepared everything and it fails on a visor problem. But I finally decided to jump. And it was the right decision.“
Shortly before jumping, in footage beamed live around the world -- on a crackly radio link recalling Neil Armstrong’s first words on the Moon -- he had said: ”Sometimes you have [go] up really high to [realize] how small you are.“
The Austrian took more than two hours to get up to the jump altitude. Mr. Baumgartner had already broken one record, before he even jumped: the previous highest altitude for a manned balloon flight was 34,667 metres, set in 1961.
Mr. Baumgartner had been due to jump from 36,576 metres, but the balloon went higher than expected, to more than 38 kilometres.
One of the first people to congratulate him was Austrian President Heinz Fischer.
”I warmly congratulate Felix Baumgartner on this great success, which was achieved with courage and perseverance and is finding worldwide attention. Austria is proud of your accomplishment,“ he wrote on his Facebook page.
The Red Bull Stratos mission was the second attempt for the skydiver after an initial bid Tuesday was aborted at the last minute due to winds.
The biggest risk Baumgartner faced was spinning out of control, which could have exerted g-force and made him lose consciousness. A controlled dive from the capsule was essential, putting him in a head-down position to increase speed.
More gruesomely, the skydiver’s blood could have boiled if there were the slightest tear or crack in his pressurized spacesuit-like outfit, due to instant depressurization at the extreme altitude.
Temperatures of -68C could also have had unpredictable consequences if his suit somehow failed.
The leap went off flawlessly, though there was a minor problem as the capsule ascended: a heater failed on Mr. Baumgartner’s helmet faceplate, meaning it was becoming fogged up when he exhaled.
After considering the options, Mr. Baumgartner and his entourage decided to go ahead with the jump.
Mr. Baumgartner’s 100-strong backup team includes retired U.S. Air Force colonel Joe Kittinger, who had held one of the records the Austrian was trying to break: the highest freefall jump, which Mr. Kittinger made from 31,333 metres in 1960.
”Let the guardian angel take care of you,“ Mr. Kittinger told Mr. Baumgartner shortly before he jumped into the void.
The giant balloon -- which holds 859,000 cubic meters of helium -- is needed to carry the Red Bull Stratos capsule of nearly 1.3 tons to the stratosphere.
It is made of near transparent polyethylene strips even thinner than a dry cleaner bag, which are heat-sealed together. Very thin material is necessary to save weight.
The skydiver has been training for five years for the jump. He holds several previous records, notably with spectacular BASE jumps from the Petronas Towers in Kuala Lumpur and the Christ the Redeemer statue in Rio de Janeiro, Brazil.
Speaking before the launch, Mr. Baumgartner said he would be proud to be the first person to break the speed of sound in freefall.
”But really, I know that part of this entire experience will help make the next pressure suit safer for space tourists and aviators,“ the jumper said.
His launch coincided with the 65th anniversary of American pilot Chuck Yeager breaking the speed of sound.

© 2012 The Globe and Mail Inc. All Rights Reserved.