Shanghai to San Francisco in 100 minutes by Chinese supersonic submarine

[Audio]

It's my mistake now to be replying to it.

Let's just chalk that one up to the long list of existing mistakes, shall we? One more, up or down, who's counting?!

rational discussion

Salivating on fantasies of new weapons is not rational discussion.

 

[MarkusS]

Peter C do you have any information about how or when a super cavitation bubble could suddenly collapse?

The Russian super cavitation torpedo never ran into such problems, from what I can find on the internet.



Thank you. That makes a lot more sense than a bubble collapse.

So it seems that this would be unsuited for manned submarines, it would be better for unmanned submarines or torpedoes.

Yes and also only for short distance. The longer the distance the higher the risk to hit something. At those speeds it is very hard to change direction, infact its almost impossible.

I believe your engineers know very well that no submarine could ever do this. What they do there is to test a new propulsion system. They must sell this for the public. So this submarine stuff is said.

We have similar projects here in germany and EU in general. Here ist done for torpedo propulsion. Anotjer problem you have is that you need enormous amounts of fuel/ energy to reach high speeds under water. Its simply not practical for large vehicles.

 

[Nova2]

Anyway I think I have found the answer to my own question, from "Mythbusters".



MythBusters Episode 34: Bulletproof Water

So being above supersonic speed (above 1,125 ft/s) will shatter the bullet after about 3 feet.

But for below supersonic speed, like with the pistol bullet (around 980 ft/s), the bullet managed to travel 2.4 metres before slowing down to non-lethal speeds, but the bullet itself continued moving and remained intact/unbroken.

So something like this...

greater the speed higher would the impact on the sub,if ever there is a bubble burst.

I still don't know under what circumstances the bubble could "collapse", or if there are any methods by which any possible collapse could be avoided.

Another question is ,why the sub needs to travel at 100km/hr for the bubble to be intact. Does higher acceleration of the sub makes the bubble more strong,stronger enough to not let the bubble burst even if it collides with a fish or something in the ocean.

 

[Audio]

So something like this...


Another question is ,why the sub needs to travel at 100km/hr for the bubble to be intact. Does higher acceleration of the sub makes the bubble more strong,stronger enough to not let the bubble burst even if it collides with a fish or something in the ocean.

Nah, the bubble is just vapour, a layer between the hull and the water. it cannot stop anything.

 

[Chinese-Dragon]

So something like this...

greater the speed higher would the impact on the sub,if ever there is a bubble burst.

Another question is ,why the sub needs to travel at 100km/hr for the bubble to be intact. Does higher acceleration of the sub makes the bubble more strong,stronger enough to not let the bubble burst even if it collides with a fish or something in the ocean.

@MarkusS who has knowledge about such things has said that super cavitation bubbles do not collapse, and in fact they are self-sustaining.

Which makes sense, since the Russian super cavitation torpedo has been active since the 1970's without ever experiencing a bubble failure/collapse. If there has ever been such a bubble failure I have not been able to find any such instances on the internet.

The more important thing now seems to be how to avoid undersea "debris" or obstacles, maybe whales or anything like that. It seems like it would be very difficult to avoid such obstacles, though maybe not impossible, depending on how the technology evolves.

Until then it seems a bad idea to use it for manned submarines. Maybe unmanned submarines or long-range torpedoes would be the best bet.

Torpedoes are already very lethal as they are, if we can use this technology to increase the speed and extend the range, it could end up being a very valuable weapons platform for many countries.

 

[Nova2]

@MarkusS who has knowledge about such things has said that super cavitation bubbles do not collapse, and in fact they are self-sustaining.

Which makes sense, since the Russian super cavitation torpedo has been active since the 1970's without ever experiencing a bubble failure/collapse. If there has ever been such a bubble failure I have not been able to find any such instances on the internet.

The more important thing now seems to be how to avoid undersea "debris" or obstacles, maybe whales or anything like that. It seems like it would be very difficult to avoid such obstacles, though maybe not impossible, depending on how the technology evolves.

Until then it seems a bad idea to use it for manned submarines. Maybe unmanned submarines or long-range torpedoes would be the best bet.
.

Nah, the bubble is just vapour, a layer between the hull and the water. it cannot stop anything.

As markuss & Audio said:

The bubble can´t collapse. It generates itself. Its an physical imperative. The problem is debris in the water that you could hit at that speeds.

this is what i was thinking as well,it should be like thin layer around the sub but not strong enough to stope anything from bursting it.

Torpedoes are already very lethal as they are, if we can use this technology to increase the speed and extend the range, it could end up being a very valuable weapons platform for many countries

Wow,now we are talking about tropedos travelling at mach speed,i better have some coffee ,nt even the Americans would like it

 

[Audio]

who has knowledge about such things has said that super cavitation bubbles do not collapse, and in fact they are self-sustaining.

Drop the speed, loose the bubble. They are self sustaining because of speed. Water is pushed to the side of the torpedo, faster it goes, faster it is pushed (displaced) Then vapour is inserted into this newly found space, reducing hull contact with water which reduces friction.

Also, in the case of Shkval, it has a specially shaped nose that deflects water from the hull and some sort of bubble generator to help create vapour.

 

[Nova2]

Drop the speed, loose the bubble. They are self sustaining because of speed. Water is pushed to the side of the torpedo, faster it goes, faster it is pushed (displaced) Then vapour is inserted into this newly found space, reducing hull contact with water which reduces friction.

Also, in the case of Shkval, it has a specially shaped nose that deflects water from the hull and some sort of bubble generator to help create vapour.

Few more pics from wiki

 

[MarkusS]

You can read about cavitation here:

Cavitation - Wikipedia, the free encyclopedia

The bubble generates itself through speed. But it would in no way stop any object impacting with the vehicle. Impacts even with small objects would be fatal.

Another problem is that the bubble collapses once the vehicle slows down. Collapsing super cavitation bubbles create enormous damage. They generate more heat then the surface of the sun and cause alot of damage on the surface of ship propellers for example. Thats no problem for a torpedo who gets destroyed anyways but for any reusable object this is dramatic

There even is a small animal, called pistol shrimp that is able to generate a cavitation bubbles. It generates such a bubble with its claw. It uses this to hunt. The shockwave the collapsing bubbles creates is hotter than the surface of the sun and kills prey. Its amazing what nature is capable for:

 

[Umair Nawaz]

Not only that if the bubble fails you are going to hit a brick wall of water instantaneously.

its success is quite possible.......search for Shakval torpedo and see how that bubble works and how its created.

 

[Nova2]

You can read about cavitation here:

Cavitation - Wikipedia, the free encyclopedia

The bubble generates itself through speed. But it would in no way stop any object impacting with the vehicle. Impacts even with small objects would be fatal.

Another problem is that the bubble collapses once the vehicle slows down. Collapsing super cavitation bubbles create enormous damage. They generate more heat then the surface of the sun and cause alot of damage on the surface of ship propellers for example. Thats no problem for a torpedo who gets destroyed anyways but for any reusable object this is dramatic

There even is a small animal, called pistol shrimp that is able to generate a cavitation bubbles. It generates such a bubble with its claw. It uses this to hunt. The shockwave the collapsing bubbles creates is hotter than the surface of the sun and kills prey. Its amazing what nature is capable for:

Wow just look at that propeller.
Any news on Northrop gurmman's electric boat that was awarded by DARPA couldn't find much info abt that project.

 

[dray]

Is there even any prototype or are we talking in thin air?? We indeed are.................!!

 

[Nova2]

Is there even any prototype or are we talking in thin air?? We indeed are.................!!

As for supercavitating tech ,it exist,there are tropedoes made by russia ,Iran & germany, with few projects underway by Northrop gurmman. As far as beijing to SF is concerned ye philhal tho khayali pulao hai

 

[kadamba-warrior]

it has already gives excellent result, it can travel from sanghai to san francisco in less than two hours. once, prototype is tested which i believe has already been tested (otherwise, there wouldn't be any news report, remember china is still the most secretive, what you see in public domain is the just the tip of the iceberg) all the issues related to safety measures will be considered. the speed will gradually be enhanced, now its less than two hours but research will try to make it within minutes. apart from military use, it will have tremendous effect on civilian underwater travel in the remote future. just imagine, after morning breakfast, one leaves home in sanghai and goes to san fransisco in minutes to do office job and then returns home in the evening

I don't get it!!! We don't even have jets that can go faster even in rarefied (or near-vacuum-like) atmospheres! Even if there were to be an air bubble all the time, how can you achieve speeds faster than Jet engines?

What kind of propulsion are we talking about?!

Heck, why can't they first do it with surface ships first -- which might be relatively easier than with the subs?

 

[kadamba-warrior]

@MarkusS who has knowledge about such things has said that super cavitation bubbles do not collapse, and in fact they are self-sustaining.

Which makes sense, since the Russian super cavitation torpedo has been active since the 1970's without ever experiencing a bubble failure/collapse. If there has ever been such a bubble failure I have not been able to find any such instances on the internet.

The more important thing now seems to be how to avoid undersea "debris" or obstacles, maybe whales or anything like that. It seems like it would be very difficult to avoid such obstacles, though maybe not impossible, depending on how the technology evolves.

Until then it seems a bad idea to use it for manned submarines. Maybe unmanned submarines or long-range torpedoes would be the best bet.

Torpedoes are already very lethal as they are, if we can use this technology to increase the speed and extend the range, it could end up being a very valuable weapons platform for many countries.

Forget the problem with maintaining air-bubbles all the time or even the problem with sea-debris!!! Or forget an underwater-craft altogether!!!

What kind of propulsion can get you from Shanghai to SF in less than 2 hours -- even in air (barring rockets)???

Remember, even the air just above sea-level itself is such a major drag that Jets fly high enough to minimize it as much as possible!