you’re right that the projectile will melt/vaporize long before reaching light speed in atmosphere, thanks to atmospheric friction, but it’ll be nothing like a shaped charge.

A shaped charge when fired turns a shallow cone/dish of metal into a cohesive hyperplastic jet of molten metal. It loses effectiveness (breaks up into smaller globs of metal) after a couple meters; hence the need for contact fuzes.

@justenuff

It could be carbon neutral, but most likely the electricity will be supplied by a fossil fuel powerplant

My 1975 Volvo has a 4 cylinder pushrod motor (modified B20E for all you gearheads out there) which redlines at 7000RPM. If we assume each cylinder fires once per engine revolution, 7000/4 = 1750 sparks per minute at each plug. I suspect the voltage discharged by the coil (which is essentially a very large, fast-charging capacitor) is significantly greater than 12V but I am not certain, I do know it is at least that. It is worth noting that on engines with a higher cylinder count (i.e. a straight six or 8-cyl, or even a 12-cyliner engine) the practical limits on engine RPM are essentially the same but the number of discharge points (spark plugs) in the system is greater so you are dividing ~7000RPM by a greater number of spark plugs which results in a lower rate of discharge at each plug. However, a well-designed electrically operated “ignition” or similar system might not experience the same limits on top speed (these are more mechanical and having to do with the high heat / friction within other parts of the engine) so a very fast rate is probably sustainable in something made to power one of these coil guns.

I don’t see any reason why this sort of design couldn’t be translated to powering the coils in a MAC/Coil gun rapidly and in sequence, it works fine in millions of vehicles every day and has for a very long time.

Cheers

Our mad Google skillz be dovetailin…

I checked out Northrup as well but none of his designs seemed to match this.
lifeboat.com/em/chapter.1.pdf
http://www.coilgun.info/northrup/home.htm

This could be the gun in question: http://www.google.com/patents?id=E4V5AAAAEBAJ

On the other hand Edwin F. Northrup was doing experiments on electromagnetic propulsion for space launches in the 1930′s and apparently built several prototype launchers, but I haven’t been able to find any substantial information about them.

Remember, in space noone can tell how far in your cheek your tongue is.

Yeah, a couple car batteries at the guys feet and a barrel a few feet long, that’ll boost it up to near light speed!

And of course leaving the barrel that fast air resistance has nothing to do with anything.

And thanks for playing.

Stuff like that.

How did this not catch on?

And if you use a high power pulse circuit precisely tuned and timed you can bypass any need for capacitors. because the caps are used in the circuits not of nesesity but because the caps have a faster discharge rate than the average battery or conventional power supply. with suficient pulse climb and timing the need for the caps disappears. another option is to switch the caps out just as fast as the coils are being fired for a recharge if caps are even used.