Calculating Force Needed for Maglev Track: Mechanics Help Needed

[thomsonm]

I'm currently working on my final year project which is building a maglev track for open days, and I'm having trouble calculating what force i need to apply to the train to make it complete one circuit of the track.

Since it's maglev, friction ~0N
Air resistance = -0.5*Rho*A*Cd*v^2 = -0.5*1.204*0.0025*0.82*v^2 = 0.0012v^2

Since i have no idea of the velocity i can't calculate the drag. Even if I ignore the force of air resistance, how would I find out how much force is required to make the train move, say, 1m?

Please help!
Matt

 

[Danger]

Welcome to PF.
I'm not a scientist, and have no knowledge of math, but I build a lot of stuff. In your case, my approach would be to determine in advance what speed you want to maintain (maybe 300 kph or so?), and back up from there to calculate what is required to achieve it.

 

[K^2]

There is no such thing. You need force to either accelerate or maintain certain velocity. There is no fundamental minimum of force required for displacement.

 

[thomsonm]

@Danger, thanks for the welcome =]
I guess a speed of say, 0.3m/s would be about right, but then I'm simply left with a resistive force, something that's constantly slowing the object. How do I work out how much of a 'kick' i need to give it at the start to make sure it reaches the end?

@K^2, I'm trying to work out how much of a kick i need to give at the start in order to make the train complete a lap of the track?

 

[Danger]

@Danger, thanks for the welcome =]
I guess a speed of say, 0.3m/s would be about right, but then I'm simply left with a resistive force, something that's constantly slowing the object. How do I work out how much of a 'kick' i need to give it at the start to make sure it reaches the end?

@K^2, I'm trying to work out how much of a kick i need to give at the start in order to make the train complete a lap of the track?

You sort of lost me on that.
A maglev is constantly propelled by the track. What you speak of sounds more like a ballistic ride, in which the thing is blasted out of the tree and coasts the rest of the way with the track providing only lift.
Am I misunderstanding what you mean, or are we thinking of different scenarios?

 

[thomsonm]

No you've got it right danger, the track is a very basic array of neodymium magnets, creating a magnetic field. By placing a superconducting disc in the magnetic field, the miessner effect causes it the expel all flux, creating a magnetic pressure and thus countering gravity.

The only propulsion on the whole track will be a pulsing electromagnet that will rapidly create a field, and by the same principles as above, push the train along.

You're right in saying that the track is only for lift =]

 

[K^2]

You said that friction is ~0N. Then you need approximately ~0N to get it going. All you need is a force that overcomes static friction, which in maglev really does go to zero. You are only working against aerodynamic and inductive drags, and that means that any force you apply will get the train going. The only question is how fast it's going to be moving.

So that's the question. How fast do you want it to go the distance. If you can figure out that, you can figure out a force. If you ask for movement at any velocity, than any force will do.

 

[wheelatharm]

I am a little unclear on exactly what you want to find. Are you looking for the impulse required, force times time, to make the train complete one loop and come to a stop after exactly one loop?
You will need to provide the mass of the train in order to do this calculation.

 

[Danger]

You're right in saying that the track is only for lift =]

In that case, I'm afraid that I can contribute no longer (not that I did so in the first place). I will be very happy, however, to learn how this turns out for you. It interests me greatly. Whether it be here, or in a PM, please keep me informed.