Guest Posted January 24, 2012 Share Posted January 24, 2012 http://www.gizmag.com/mitsubishi-air-lu ... tem/21196/ Didnt the nzl americas cup team try something like this years ago? Link to post Share on other sites
too_tall 15 Posted January 24, 2012 Share Posted January 24, 2012 I believe that there have been Military vessels built using this concept, but utilizing jet propulsion, and achieving pretty impressive top speeds ( in excess of 100 knots ). I am not sure if they were trial vessels or actually in service. I believe them to have been multihulls. Link to post Share on other sites
Grinna 2 Posted January 24, 2012 Share Posted January 24, 2012 The high speed offshore power boats have stepped hulls and channels that suck air in and help the hull to lift out of the water ... or at least that's what I was lead to believe they do. I'm guessing that only works at higher speeds than would be typically encountered in sailing boats. Any bubble generation system would need to produce larger gains than the weight, complication and energy requirements the system would cost to be worthwhile. Link to post Share on other sites
Variant 2 Posted January 25, 2012 Share Posted January 25, 2012 I was much more impressed by this http://www.gizmag.com/ghost-super-cavit ... oat/21137/ Super cavitating Wow! like this torpedo http://en.wikipedia.org/wiki/Shkval 200 knots! and this was in the 70's I wonder how fast they are now. Link to post Share on other sites
too_tall 15 Posted January 25, 2012 Share Posted January 25, 2012 The military ones I have heard of utilized jet turbine engines for propulsion and also for the generation of the supercav barrier - I believe they were double skinned on the hull with some form of material which allowed air to pass out, but, presumably, not allow water in. This, of course, is from reading random web and magazine articles. How accurate that information is, is anyone's guess. I do know that it is proven to work, but on a destroyer sized vessel, well, that could be a different story. Of course, its less ridiculous than intending to have linear accelerators to launch satellites... http://en.wikipedia.org/wiki/Mass_driver http://www.ohgizmo.com/2007/01/03/launc ... slingshot/ Yes, they are actually seriously considering and investing massive amounts of research money into this concept. If you have time, reading through the linked sites on the wikipedia site, you will find that one of the more likely to work concepts is to have a launching tunnel - 160Km long - which is in a vacuum, to reduce the friction on the object being launched. This will be sealed with a plasma gate... But the truly impressive part is that they plan on magnetically levitating this thing 6KM above the earths surface... Not too sure about this concept to be honest!. I also read that its expected to draw 1,000,000amps at 11Kv. That's 11gigawatts. About 7 times the output of Huntly powerstation... Link to post Share on other sites
Guest Posted February 3, 2012 Share Posted February 3, 2012 I was much more impressed by this http://www.gizmag.com/ghost-super-cavit ... oat/21137/ Super cavitating Wow! like this torpedo http://en.wikipedia.org/wiki/Shkval 200 knots! and this was in the 70's I wonder how fast they are now. ...ask that guy in the firing station on the Kursk Link to post Share on other sites
wheels 543 Posted February 3, 2012 Share Posted February 3, 2012 Yes, they are actually seriously considering and investing massive amounts of research money into this concept. If you have time, reading through the linked sites on the wikipedia site, you will find that one of the more likely to work concepts is to have a launching tunnel - 160Km long - which is in a vacuum, to reduce the friction on the object being launched. This will be sealed with a plasma gate... But the truly impressive part is that they plan on magnetically levitating this thing 6KM above the earths surface... Not too sure about this concept to be honest!. I also read that its expected to draw 1,000,000amps at 11Kv. That's 11gigawatts. About 7 times the output of Huntly powerstation... Either it is something waaaay off in the future, like the year 2525, or someone writing on Wikipedia is just full of dribble. Link to post Share on other sites
Guest Posted February 3, 2012 Share Posted February 3, 2012 Arthur C Clarke came up with a much better idea of a space elevator. Put a satellite into geostationary orbit, then lower a string down to the surface of the earth with a box on the end. The whole thing spins very slowly and there is an identical sting and box on the other side to balance it. To an observer on the earth the box drops down out of the sky, sits just above the ground for a brief period while you load it with whatever, then lifts back up into space. When he conceived it , there was no material known that you could build it out of, but today there is. The accelerator thingy has been discussed at length in the past, no good for people coz they would get turned to mush, might even be a bit rough on satellites. I've never understood why they haven't investigated large dirigibles. They can get to near space altitudes, launch from there and you'd need a whole lot less fuel to get into orbit. Link to post Share on other sites
wheels 543 Posted February 3, 2012 Share Posted February 3, 2012 The issue getting into space or even orbit for that matter, is not actually in leaving the ground, it is reaching a speed to obtain an orbit. Depending on orbital height, you need a speed of ruffly 17,000Mph minimum to remain in an orbit. A Satillite remains in orbit due to it "constantly falling". It is traveling "forward" just enough to keep falling over the "front" of the Earth. Gravity keeps trying to pull it down and the speed forward keeps it just out over the "front" of the earth. So the result is that it maintains a constant orbital height or distance. So that's the part that is the problem, the speed. Launching from a high altitude removes only a small part of the overall equation of getting to speed. In all, the atmosphere is actualy very thin and the thick part of it is very very thin when you compare the overall distance up the Satellite has to reach. The plus factor of a high altitude launch is having less wind friction, but you have less distance to reach speed within, so you need greater acceleration. There is a saving, but the saving has to factored into the greater equation. The negative factors are, getting the entire craft to an altitude to start with. Remember that winds are a whole lot stronger up high above the ground then you reach altitudes where the temp drops to huge deg in the minus numbers, then you go through a belt that the temp rises to huge temps the other way into the positives. Which by the way are still all major issues in regards to using AC Clarkes Elevator string. So all this is hence the reason why the theory of having a space platform to launch from and low orbit space craft to reach that platform is still the theory long term for deep space exploration. Not to mention that a very large "mothership" can be assembled in spce from smaller compnents we lift up there and then the entire thing can be sent off in a direction like Mars for instance an enter orbit as a space platform to then have a smaller reusable craft to make platform to Mars surface trips. All still a long way off though, as the cost is..errr...astronomical. Link to post Share on other sites
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