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Flying saucers are very large and have spherical centers not to carry passengers but instead to carry the fuel. Flying saucers solve the fuel weight problem by carrying methane gas in the center in an envelope. Methane is half the weight of air, so the envelope can carry its own mass and also part of
the spacecraft to the top of the atmosphere. This hybrid aircraft is a cross between lighter than air LTA and standard aircraft.Because of it's similarity to LTA (blimp) aircraft, it will tend to be extremely large (football stadium large) in order to take advantage of the volume to surface area trade off. However, like the Eros aeroscraft, it can also carry hundreds of people into space.
The structural elements of flying saucers are pulse detonation tubes placed radially around the outside of the spherical envelope in a ring. These PDE engines burn air and methane while in the atmosphere. The passengers in a flying saucer actually travel in the ring of the saucer. At the top of the atmosphere, the flying saucer changes shape, the spherical envelope disapears to make the vehicle super-sonic and the vehicle starts burning stored LOX rather than the atmopheric oxygen. When the saucer is in space it continues to spin and thus provides artificial gravity like a space station.
To refill a flying saucer with methane you dump organic matter in the center envelop, add a special microbe...(as ldischler suggested), that is why crop circles appear where flying saucers have been.
Aeroscraft (popular science)
http://www.popsci.c...flying-luxury-hotel
Tomorrow's cruise ship will sail through the air, not the water [rslippert, Jul 22 2008]
Pulse detonation engines
http://en.wikipedia...e_detonation_engine
[rslippert, Jul 22 2008]
Drag at the Wikipedia
http://en.wikipedia..._%28aerodynamics%29
Nothing to do with weight [neutrinos_shadow, Aug 04 2008]
aeroscraft video
http://www.youtube....watch?v=JHRzqlKGZyE
YouTube video of the aeroscraft [rslippert, Aug 15 2008]
[link]
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Gaseous methane won't last very long as a fuel, particularly in a application as power-hungry as flight. |
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Re: density, the gaseous methane would have to be a _very_ large volume (and low pressure) to result in a lighter than air craft, if indeed that is what you're saying. |
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Depends on the type of structural material. Small UFOs are boring anyways. |
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I agree with 2 fries short of a happy meal. |
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But you do know that just because the saucer is spinning that it doesn't create gravity, or make things go down. The space station's designs are things are on the wall, so like the “Gravitron” at a carnival, where you are spinning fast and the bottom drops out, its the inertia that pushes you to the walls. |
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Things could get pretty harried whenever you change atmospheres from a planet to space.
A lot of tossed cookies. |
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It's more interesting to explain it with 19th century technology: Flying saucers have spherical centers not to carry passengers but instead to boil water for their steam engines. The boiler is fired by burning corn taken from fields--thus those crop circles you see everywhere. |
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Where are you getting the supersonic air to ignite the PDE tubes? I've been looking for some and my old supplier is out. |
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Texticle is correct, such a vehicle would need to be very large to trade off surface vs. volume. But then that is why blimps are large...no problem. So yes...if this is how a flying saucer is constructed...you can tell a fake from the real thing by it's size...they must be very large to do this gas fuel envelope trick. |
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Now respond to my energy density qualm. |
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If you can make it large enough you can carry any extra weight. But you'll need a huge amount of fuel to carry it from "upper atmosphere" to "space" |
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I also agree with the recomendtions 2 fries made which he did not delete. |
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I just randomly do that sometimes. |
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No...I disagree with Voice....You need a small fraction of the fuel to carry it from top of atmosphere into space because the air coefficient of friction is so small. The same reason jets fly so high in the atmosphere. |
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// Methane is actually half the weight of air // |
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"Specific gravity (air = 1) (1.013 bar and 21 °C (70 °F)) : 0.55 " |
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True; but that means the lifting power is fairly modes compared to, for example, Helium. |
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A 1000 cubic metre balloon filled with methane can therefore lift about 350 Kg ..... not a great deal. |
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If the outer ring spun, it would stablize the affair gyroscopically. The center ball could then be used as a castor wheel to travel along roads. Some nonspinning and nonrolling part would need to be affixed somehow (I know, WIBNI) to carry the brake lights, or it would not be street legal. |
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rslippert, its true that there will be much less friction in the top of the atmosphere, but you're also talking about moving a huge object. |
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You are all assuming that this is a lighter than air craft...it is not. It does not need to be lighter than air only that it solves the fuel weight problem by carrying its own mass. Such a vehicle is a hybrid between LTA and heavier than air aircraft, similar to the Eros Aeroscraft. |
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// Gaseous methane won't last very long as a fuel, particularly in a application as power-hungry as flight.// |
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This issue is addressed in the size. As the size grows, the volume to surface area relationship changes. Note, the drag of a aircraft is related to its weight. If you decrease the surface area in proportion to its volume you also decrease it's drag. Weight is also decreased by displacement lift of the LTA gas, so the fuel requirements go down for two reasons as the vehicle becomes bigger. |
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I get the feeling you are trying to bluff your way through the physics, hoping that your audience will be bamboozled by the terminology. This tactic does not work in expert company. If you still think you are right, please elaborate, as almost every sentence above is equivocal at best. If your explanation withstands scrutiny, then you will get my sincerest apologies for bringing it into question. |
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//Note, the drag of a aircraft is related to its weight//
Drag has nothing to do with weight (linky), except when considering the drag due to lift from wings. |
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That's downright mean...Texticle.... and also a falacy...you are attacking me and not my arguments.....so just worry about your own "bluffing your way through the physics" and your own "bamboozling by the terminology"!! Mr. flamesticle. |
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The Energy density is a relationship between the mass and the total energy. Again...this is addressed by the size. as the size grows the surface area related to mass grows slower than the volume of fuel in the surface area vs. volume relationship. That same relationship, again, is why this is a large (ok, very large) vehicle. Relative to the mass, the large vehicle has a larger energy density per unit mass. So it is just a matter of how big does this get....and I'm not done with the simulation yet so give it a rest. But I think it becomes feasible at around football stadium size, which does not kill the concept if you can take a stadium full of people and equipment up into Earth orbit. |
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PDE tubes do not need supersonic air, they create supersonic air...that is the definition of detonation. You simply ignite the fuel air mixture in the tube with a DDT (deflagration to detonation) transition (detonator). The flame propagation operates at supersonic speeds. In spinning saucers, this concept, the air is not scavenged by the reflected pulse, but allowed to refill naturally as the tube rotates 360 degrees. This concept is not pulse scavenged then, and thus has none of the problems associated with (and efficiency loss due to) pulse scavenged PDE. It is a single shot at a time PDE. Which is a lot easier to do than rapid pulse detonation at thousands of pulses per second. That means you need many more engines (PDE tubes) to sustain thrust, but the tubes also act as the structual elements of the vehicle which would be there anyway. |
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Concerning the //power-hungry as flight question // The optimized operating speed of such a concept is well below that of "normal" aircraft. Because drag is a velosity squared relation, the form drag drops with the square of the drop in speed. Induced drag is lower because the vehicle does not change attack angle but stays at an optimal attack and also has lower mass per unit lift. The optimization of the relation between Induced drag and form drag is thus at a lower speed. The total resulting drag is almost half the drag of a normal aircraft. This is similar to the Eros aeroscraft, except the fuel weight also carries itself so it is more efficient than aeroscraft. Please see the aeroscraft video...quite the mind blower and a little wasteful of space, but the basic idea of size is there. This is truly where we are headed with aircraft and spacecraft. |
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The basic idea is that if we want to get into space cheaply, it is with a very large hybrid aircraft like the aeroscraft. The x-prize "Spaceship-One" vehicle did nothing to solve the problem of cheap and affordable space travel. I consider Spaceship-One a failure. |
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Spaceship one did exactly what it was intended within the rules it was allowed to play in. |
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I just dont understand the ring concept. |
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This idea is basically a balloon of methane with a ring around it and some PDE's to help it get up there. |
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Now please back up your idea with some math. I am not a learned student, just a fertile invetive mind. That being said, even my feeble number crunching skills are left wondering some basics. |
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Lets assume 10 people is what you want in this thing. |
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How large would the sphere have to be? |
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How much methane would be required? |
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How thick would shell of this sphere have to be just to support it's own weight on the ground? At what altitidude will the lift effect of the methane be negated (air gets thinner at altitude I think). |
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How thick would the shell have to be to reamain a really really big sphere with some, likely by now, liquid methane in it? |
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Just give us some really basic numbers, otherwise there is no point in trying to make this concept into an idea you can actually argue over. |
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The drag/weight comment makes me wonder if there is not some magic in this idea. |
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//Spaceship one did exactly what it was intended within the rules it was allowed to play in.// |
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Spaceship One may have done what it was intended to but not what is needed to get more people and equipment into space. I think the X-Prize contest is not setting the goals that drive the development of a true privatized space industry, only a space ride but no way to stay up there. The automotive X-Prize has the same problem to the point where the auto companies (or at least Ford) does not take this seriously enough to enter the contest.
I plan on adding an automotive vehicle solution using twin engines front and back that is a better way to do VDE (variable displacement engine), as well as independent all wheel drive. |
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//I just dont understand the ring concept.// |
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The bottom half of the vehicle (ring) is hard and made of structural materials like typical aircraft. The upper soft envelope element, is supported by internal pressure like a blimp. This only covers about half of the area of the top of this discwing concept. The Aeroscraft concept uses this soft top/hard bottom hybrid concept also, however the optimal configuration of this aeroscaft concept will be a ring because a sphere has the optimal volume to surface area ratio of R/3.
Equations: Volume_Sphere = 4/3(PI)r^3 ; Surface=4(PI)r^2
Ratio Area/surface = 4/3(PI)r^3 / 4(PI)r^2 = R/3
Thus, the aeroscraft hybrid concept (when optimized) become this discwing concept.
The only problem is the hype of flying saucers has jaded this concept. |
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//This idea is basically a balloon of methane with a ring around it and some PDE's to help it get up there.// |
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It is a hybrid between aerodynamic (conventional) aircraft and aerostatic (blimp) aircraft. Similar to the aeroscraft concept. However, the aeroscraft concept will only be optimal when the envelope is spherical, not just a half sphere like aeroscraft. So, basically this is an optimal solution of the aeroscraft concept, which solves the fuel weight problem of getting into earth orbit. |
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