Half a croissant, on a plate, with a sign in front of it saying '50c'
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Gas powered launch vehicle

Launch vehicle uses natural gas to launch.
(+1, -1)
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First, dig tunnel through centre of earth. (Now that was not too hard was it?)

Cover one tunnel entrance with Glad wrap.

Position launch vehicle, nose down, at other tunnel entrance.

Fill tunnel with natural gas.

Release launch vehicle to fall towards centre of earth.

When launch vehicle reaches speed of sound strike a light behind launch vehicle to ignite gas.

Gas will burn and expand accelerating the launch vehicle even more.

Because launch vehicle is travelling above speed of sound the gas ahead of it will not be blown out of the tunnel and the flame front will not overtake the launch vehicle.

Launch vehicle will reach escape velocity by the time it exits the end of the tunnel.

(Acknowledgements to the Saddam Hussein 'super gun' of the 1980s)

KiwiJohn, Dec 02 2003


       Robert C, the effects of aceleration while falling will be pretty much offset by the effects of deceleration once past the centre point. However for all this time the gas is burning and adding momentum to the launch vehicle.
KiwiJohn, Dec 02 2003

       I don't think that the propogation of the pressure wave would reach excape velocity. So, no space for you!
my-nep, Dec 02 2003

       "I don't think that the propogation of the pressure wave would reach excape velocity. So, no space for you!"   

KiwiJohn, Dec 02 2003

       I don't know what SH intended to use in his super gun but the object was to achieve near orbital trajectories.
KiwiJohn, Dec 02 2003

       Now boarding, the Sydney / Reykjavik Express.
RayfordSteele, Dec 03 2003

       I would give bread to this if it were a lunch vehicle, and could hand off a meatball sandwich as it exited the core of the earth. If I gave it the bread first, it would probably be nicely toasted by the burning gas.
bungston, Dec 03 2003

       I hate the taste of toast made over a gas flame ... however, greek food could be somewhat more interesting
Letsbuildafort, Dec 03 2003

       This won't work.   

       KiwiJohn, you didn't make the chute a vacuum.   

       The natural gas will have combusted before your rocketmen get their seatbelts on.
Tiger Lily, Dec 03 2003

       Yes, with a vacuum tube and the sandwiches mounted on the front of the lunch vehicle, they would be toasted (and cheese melted!) by radiant heat from the earth's core.
bungston, Dec 03 2003

       I'm fairly sure now this rocket launch won't happen using a vacuum tube either.   

       The natural gas won't have an oxidizer to allow combustion to take place.   

       bungston, you will have to settle for dropping the cheese sandwhich down the the hole yourself then 'bobbing' for it when it comes back through to your side. Make sure you wear your safety glasses...
Tiger Lily, Dec 03 2003

       Maybe its just me, but wouldn't the tunnel colapse long before you could fill it with gas? And you'd say "we'll put something holding it up!" And I'd say "what about gravity inside the center of the earth? Isn't it a tinny bit higher than up above? Or the extreme problem of breathing when your lungs can't move and are trying to implode, while your eyes want to move out of your cranium!" And even maybe you'd say "We'd build a machine resiliant enough to do it!" "What about the heat inside the tunnel? Wouldn't it melt the machine WAY long before you get near the center?"   

       But out of this the biggest problem would be: Wouldn't the heat blow the gas before you wanted, and how would anything produce that much gas? Maybe we could fill it with politians from all over the globe and wait until they release that much methane... Just imagine the match to light up that thing!!! AAaaaaaaaahhhhhmmmmmmmmmmm........
Jolly_john, Jun 11 2004

       John... gravity is less the further down you go. At the Earth's centre, you weigh nothing.   

       Gravity pulls two masses towards each other, hence on the earth's surface, all the mass of the earth is below you, and you get a strong downward pull. At great depth, a lot of Earth is above you, pulling upwards, and less is below you pulling downwards, so you weigh less.   

       Well, that's it approximately... in reality, it's a bit more complex, and the gravitational effects of the "shell" of mass whose radius is greater than the distance from you to the Earth's centre actually cancels itself out and can be ignored.
david_scothern, Jun 11 2004

       Very Jules Verne. The tunnel dosen't need to go all the way through the center of the earth, just at an angle (I've read that such tunnels takes the same amount of time to travel, about 45 minutes) at the 1/2 way point it will reach max. velocity. the gas can be ignited at this point to at least keep the rocket from slowing down.
the great unknown, Jan 09 2007


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