# Is it possible to build a vertical particel accelator?

1. May 6, 2010

### future_think

In this instance forgo the particle part.

I'm thinking more here like the way a railgun works. Or how some rollacosters can take you from 0 to 60kmph.

Lets say we wanted to make a railgun that uses a large loop to continual increase velocity to a desired point, then release it into an adjacent chamber to let it launch vertically.

How would gravity affect increasing the velocity? I'm thinking since we are using a vertical loop the effect of going up would be offset by when it is going down.

Anybody have thoughts on a device like this?

2. May 6, 2010

### CompuChip

It would be kinda inefficient.
Since the gravitational force is conservative, in the ideal case you would only gain the energy on the way down that you have first pumped in to get it up.
In a realistic case, due to friction, you will give it a little less kinetic energy than you input.

So in that respect, building a vertical accelerator would in any case not give an advantage over a horizontal one.

3. May 6, 2010

### future_think

What about the notion of keeping the accelerator horizontal with the goal of launching a ship after a certain horizontal velocity is obtained.

There has to be a more sufficient way to launch space-bound ships then burning insane amounts of fossil fuels.

My thinking energy put into accelerator doesn't need to be fossil fuels. Once the ship goes vertical and reaches X height then the rockets could fire. Since the ship would already be in motion a x velocity then the rockets would have a much greater effect with less fuel expenditure. (much like the current multi-rocket ships rotate firing).

4. May 6, 2010

### ZapperZ

Staff Emeritus
You ARE aware that the power required to provide all those magnetic fields and all the pull to cause either a lift, or a launch, comes from burning of fossile fuel as well, aren't you? All you are doing is add even more layers between the burning of fuel to the actual propulsion, which makes it even more inefficient.

Zz.

5. May 6, 2010

### future_think

Except not all energy is from fossil fuels. .. Solar, Wind, Nuclear..

6. May 6, 2010

### ZapperZ

Staff Emeritus
It would still be inefficient if it had to go through several stages before it gets to the end. That's the point.

Zz.

7. May 6, 2010

### willem2

In principle, launching a spaceship with a railgun could save a great deal of energy, because you're no longer have to accelerate your own fuel. Two reasons this isn't used
at the moment are:

It needs to be a really long rail, or the acceleration will kill everyone inside.
(unmanned ships could skimp a bit here)

You need an evacuated tunnel to an altitude of about 30 km, so air friction doesn't slow you down again. (and probably destroy the ship).
The advantage of using rockets, is that the largest speeds are only reached once you're out of the atmosphere.