Theory 1 - The straight line rail gun for sheer speed
You build the gauss rifle in a straight line, much like the toy example. You build it with the highest durability magnets possible. I wonder what type of speeds you could produce before the acceleration physically destroys the device (magnet breakage)
The Navy and Air Force are developing seperate 'kinetic energy' weapons that use this principle. The Navy version is a replacement for the Tomahawk. The Air Force version replaces nukes. The idea behind them is simple, a large tungsten rod flying at tremendous speeds that hits with the energy equal to a small meteroite. The Navy version is launched from a ship, of course. It will pack enough KE to destroy buildings and hardened bunkers. The Air Force version is a tungsten rod dropped from a satellite that hits with the impact force of a meteor or small comet. Total devistation like a nuke, but no radiation.
The problem you brought up is the same that the navy and Air Force is having. The rods that they use are tungsten to handle the high heat. They have fold-out fins for manuevering and just enough electronics onboard to enable GPS guidance. The problem is the sudden accelleration destroys the electronics at speeds that are too slow to be of any use for a kinetic energy weapon.
The Army has it's own version that is to be used as an anti-tank weapon. I don't know too much about that one.
Here's a few links:
Army
Navy
Navy
Air Force
Theory 2 - The Electromagnetic Circle
Same principle, inside the vaccuum tube, but this time you use controlled electromagnets to propel the projectile. Im not sure if this is possible.. I think it is? Could you not build it so that the magnets are underneath the track and that ball never has to collide with the magnet? It is turned off and on in a controlled manner (laser?) Basically the first magnet atttracts the projectile, is shut off, and the next electromagnet is turned on and it attracts to there and so on and so on going in a circle. Now we have this in a vaccum tube we remove the air resistence. We thus have limitless speed ( air speed that is ) We still have friction. This principle uses only one projectile.
This is how an electric motor works. You have a rotor, which is a perminent magnet on a rod, inside a stator, which is a series of coils wrapped around the rotor. Since the coils are wound seperate from each other, you can pulse them with electricity in a circle around the rotor. The rotor is attracted to one of the coils and moves to align it's magnetic field with the stator. Then when it is just about there, the electricity to that coil is switched off and the next coil is switched on, causing the rotor to move toward the second coil. This continues, the stators attracting the rotor in turn until the rotor has moved 360 degrees. Then the first stator coil fires again. The result is that the rotor continuously rotates, always trying to get aligned to the stators that switch on and off. Kind of like dangling a carrot in front of a horse.
I'm not sure how fast you could get a large object moving. This is the principle that particle accellerators use. They use electromagnets to attract and repel the molecules that move around the accelerator. If you think about the massive size and energy consumtion required to accellerate something like one atom of gold, I'd say you couldn't feasibly get a large object moving very fast.
