The Physics of Rail Guns & B5
I. The concept of the electric gun.
Essentially electric guns come in two flavors, rail guns and coil guns.
There is technically such a thing as a maglev gun but it is closely related
to the coil gun concept. As I've explained in previous posts the rail
gun is a very simple device consisting of two metal slats, a conductive
II. The physics behind the guns.
A) Rail Guns
Vector mechanics is the heart and soul of what makes rail guns work.
Without going to in depth let us say that all of the most important equations
for a rail gun can be derived the definition of the magnetic field (B).
The final equation to calculate the force exerted upon the rail guns
B) Coil Guns
I think I may have said this before but coil guns are no where near
as simple as rail guns. The force can that will act upon your projectile
is not easily calculated. Suffice to say that in depth knowledge of quantum
physics is a prerequisite if you want to discuss the ways in which magnetism
Well, now that I've bored you all with an ton of fairly vague and compicated math let us turn to the obvious drawbacks of these systems.
A) Rail Guns
A rail guns most glaring problem is the amount of space required for
all of its components. The barrel alone has two very important and quite
seperate electrical systems operating, electromagnets and the rails. Because
you can not generate any force on a current unless you have a pre-existing
magnetic field you simply must have magnets set perpendicularly. Magnets
require their own set of controls and power sources which consumes space.
The rails require a substantial and very hardy power source capable of
delivering enormous currents on command. These also take up space. For
B) Coil Guns
The main problem that coil guns have is inefficiency. This problem is caused by the electromagnet. Each loop in the electromagnet can be imagined as its own little magnet. As the projectile travels through the core of the magnet more and more of these loops end up behind it, slowing it more and more. The trick is to time it so that the next magnet in line turns on, the current magent in use turns off, and the projectile keeps speeding down the barrel. At best a single magnet can only exert positive acceleration upon the projectile for half of its length. After the mid point it acts like a brake. Now the next magnet in line can be used to overcome this effect but, the last magent in the sequence always loses half of its effective acceleration length.This can lead to a number of problems not the least of which is unsteady projectile acceleration and even braking of the projectile while inside the barrel. Maglev devices also suffer from this problem.
The second drawback to the coil gun is similar to the rail gun. Namely it requires a very hardy power source that can nearly instantly supply vast amounts of current. These systems consume space. Coil guns have an additional drawback in that they require complex timing circuits to drive the magnets. These may not consume much space but poor calibration can have serious negative effects on the gun's performance.
IV) The Benefits
Lest you think all is gloom and doom I will now tout the benefits of these devices.
A) Rail Guns
The primary benefit from the rail gun is that it is simply much more
powerful than a conventional gun. I'll use an example I've used in the
past. The main gun (I forget this weapon's calibre) on a U.S. Battleship
can deliver a whopping 125kJ of energy to its target. By comparison an
80mm prototype operating at Green Farm was able to deliver 5MJ (almost
50 times as much energy) to its target. Not only did this much smaller
gun pack a bigger punch but rail guns also have vastly increased ranges
over conventional artillery. At such high rates of velocity and large
B) Coil Guns
The primary advantage of coil guns is also increased power. Although to a somewhat lesser extent than a rail gun. This is accomplished by converting the acceleration curve from an exponential curve that quickly goes negative to a sinusoidal that spends virtually all of its time in the positive quadrant. While I have no real life examples just imagine that your projectile gets a fresh kick down the barrel as each magnet in the coil gun turns on.
V. Game Terms
Getting more "on topic" as it were. I can definatly see where many primitive races including the EA used or continue to use rail gun technology. However, the damage for these weapons would more appropriately be piercing. This is because, unlike a hill, mountain, or other planetary surface feature, space going vessels simply lack the mass and density to prevent a high speed projectile from going right through them. However, we are stuck with a game mechanic. So to explain it away we could simple say that these weapons fire a high explosive round with a contact fuse. Their rate of travel is so high that they affectively ignore the armor on the location where the impact and within nanoseconds detonate causing great destruction to the local area of the impact. These explosives are not themselves capable of penetrating any armor which explains why excess damage is lost.
Moving on we see that the EA abandoned rail gun technology for the most part after the Earth-Minbari War. I suggest that barrel wear was a contributing factor to this. However, the new Warlock Destroyer employs rail guns. We can simply explain this away by stating that new space saving power equipment allowed multibarrelled rail guns to be employed. Cycling barrels would dramatically increase a weapon's useful lifespan without actually improving it's overall characteristics. Although, a faster rate of fire might be appropriate.
The use of coil guns seems logical as an explantion for the Centauri
matter cannon. The smaller damage is actually likely a smaller explosive
charge and has nothing to do with the weapon's muzzle velocity. On the
whole it requires greater technological finesse to employ these weapons
which is in keeping with the Centauri being a more advanced culture than
Earth. It would be interesting and appropriate to see variations of these
weapons that had piercing mode as an option. I do not believe that these
weapons would be useful on tanks although their value as artillery either
on the ground or from orbit would be very great indeed. Just something
to keep in mind for Gropos.