Naval History Forums

lwd wrote:Thoretically I believe the max velocity of a em gun is around .1c.

1. Point one "C."? I'm sorry for my ignorance about more advanced theories through velocities and other physics subjects, I'm taking that class next year.

2. Does the heat exchange into the barrel also follow the cubic formula you have explained to me? Otherwise the 3in idea of putting the EM idea into an Otobreda wouldn't be entirely feasable... due to the RoF going down from 120 per minute to only ten to twenty per minute...

2. Does the heat exchange into the barrel also follow the cubic formula you have explained to me?

No. Volume varies wth the cubic of the lenght, surface with the square. Heat exchange ocurrs over a surface, so a square applies.

So a 3in railgun would have the same heat problems as a 16in one?

1. Point one "C."?

"C" means speed of light, so .1 C equals 30.000 km/s.

So a 3in railgun would have the same heat problems as a 16in one?

i don´t know why there is a heat problem, as there is no combustion.

1. I should have known that. E=MC^2.... duh!

2. The fact that there is a projectile moving that fast through the barrel and the air in the barrel means that the plasma created by the friction burns the lining and bore of the barrel. Very little of the electromagnetic energy is transfered to the projectile, and thus the energy wasted is thrown into the barrel.

3. NEW IDEA! What if they threw all of the energy into the projectile straight through a copper plate, and the permenant magnets in the barrel would cause the projectile to throw itself straight through the barrel...?

I'm not at all sure that rail guns necessarily have what most would consider a "barrel" indeed I think some of the intial ones only had the rails. Of course the early ones tended to need a new set of rails with every shot. If you haven't looked at these sites you may find them interesting
http://www.navweaps.com/Weapons/WNUS_Rail_Gun_pics.htm
http://www.powerlabs.org/railgun.htm
http://sci-toys.com/scitoys/scitoys/ele ... ilgun.html
http://www.powerlabs.org/coilgun.htm
http://www.coilgun.info/about/home.htm
http://www.coilgun.eclipse.co.uk/

Okay... havent been able to find enough about the dimensions on a potential system, and had a set of great ideas the other night to refine my design. My last block of this BB had a really blunt bow... and it was making me mad... so I was finally able to fit a faster bow on it by shifting the superstructure and everything protruding from the main deck back 50 ft. 40-45 knots. Enjoy!

Very cool!

Thank you! I am currently working on a true 3D model of this warship. I am currently having trouble with making the forward bow flare correctly... I might have to make the bow in many seperate pieces.

marcelo_malara wrote:

"C" means speed of light, so .1 C equals 30.000 km/s.

for the good order (i know it was just a typo but you never know when the Science Police are watching)

c = 299,792,458 meters/second (in vacuum!)
or approx. 300000 km/s
or approx. 186000 miles/s

E = mc²
where E is energy, m is mass, and c is the speed of light in a vacuum

Legend wrote:So a 3in railgun would have the same heat problems as a 16in one?

Missed this the first time around. The heat problem with rail guns initially was due to friction but there's also "waste energy" as no process is 100% efficient. As to which has the greater problem with heat it would depend on what you are doing. If both have the same KE then the 3" round is going to be moving a lot faster and thus heat generated by friction will be more of a problem in this case. If they both are fired at the same velocity more energy has to go into the 16" round and it's larger diamter means more friction so more of a heat problem iwth the 16" round in this case.

So... If this was to be thought out and designed... assumingly the architects would want the same velocities... because the 3in is going to have the faster reload obviously. The more I think about it the more it comes to me that this system would require a MASSIVE AMOUNT OF POWER! The 3in guns would be bearable on the electrical system... but multiple 16in guns would really do a toll on whatever generation system and storage system the ship would have...

At a guess it wouldn't be too much trouble to generate enough power on a BB for these guns. The problem would be storing and pulseing it. There's also the question of what you want the round to do. When they were looking at arming a tank with one I'm pretty sure they were just planning on using solid shot. Works fine vs tanks or planes or for that matter missiles and torpedoes. However if you want to effect ship a simple KE penetrator may not be optimum. Especially with todays ships you may just punch a little hole in one side and out the other.

Way too overkill... but for a bombardment role it would be insane! The battleship could use the secondaries (3in) as anti ship guns... because lwd's point is completely true. A 16in railgun would be almost overkill for even a bombardment role!

Might work pretty well for taking out an astroid. Of softening up the area if somone wanted to do some Lunar mining .....