In World War 2 the largest battleships could lob shells 30 miles (48 km) or more.
Missiles quickly replaced guns on warships and today can travel for hundreds of miles
before detonating at their target.
Yet missiles can be prone to spoofing, or jamming, and can potentially be intercepted
and destroyed.
Despite boasting some of the most advanced missiles in the world, the US military quickly
realized that there was still some merits to good old fashioned 'dumb' projectiles,
but instead of looking back at the past, the US looked toward the future.
Welcome to another episode of The Infographics Show- the US Military's most powerful cannon,
the electromagnetic railgun.
Even before the age of sail with its famous frigates and ships-of-the-line full of cannons,
man has been putting long range weapons aboard ships.
Early naval vessels were often equipped with catapults or ballistae, and their purpose
was much the same as it remains today- help soften up enemy coastal defenses or destroy
other ships at sea.
Today's military warships however seem to have all but completely replaced traditional
naval artillery with something completely new- the long-range antiship missile, or land-attack
cruise missile.
While superior in every way to traditional cannons, defensive technology has very quickly
caught up and today's high-tech missiles are all too often at risk of being countered by
enemy missile defenses.
High powered lasers can burn out a missile's guidance system at long range, powerful jamming
pods can interfere with a missile's targeting, electronic warfare suites can even hack into
a missile's active guidance and disrupt it, and smaller, more agile missiles or high-speed
computer controlled chain guns can intercept them mid-flight.
While a saturation strike involving multiple missile volleys can overwhelm even the US's
vaunted AEGIS missile-defense system, there still seems to be room for traditional artillery,
but it wasn't until recent technological developments produced an alternative to modern missiles
that was even remotely comparable.
Even the big guns of World War II era battleships were too slow to fire, and the projectiles
lacked enough velocity to reliably strike their targets.
In battles of the era, the majority of attacks resulted in misses, as even a slow-moving
battleship dodging another battleship's volleys could move out of the way of projectiles traveling
at only a few hundred miles an hour if it was far enough away.
It wasn't until ships closed in to extremely close ranges that hits were guaranteed, and
at medium to long ranges battleships relied on radar and spotter planes to slowly train
their guns onto a target.
Faced with modern and much faster ships, this is clearly not a viable alternative to missiles.
Yet the development of the electromagnetic railgun seemed to solve all of the follies
of traditional cannons by firing projectiles at incredible speeds upwards of 1.6 miles
a second, far too fast to be easily dodged.
But what exactly is a rail gun?
In essence a railgun is nothing more than a large electrical circuit that uses magnetism
to accelerate a projectile to greater speeds than possible by traditional gunpowder charges-
or even most missiles.
The railgun consists of three parts: a power source, a pair of parallel rails, and a moving
armature.
The power supply generates current in the millions of amps, or enough to power a few
thousand homes.
The rails are long lengths of a highly conductive metal such as copper and can range from 4
to 30 feet (1-9 meters) long.
The armature is a device that bridges the gap between the two rails, and is typically
a solid piece of conductive metal or a conductive sabot- a carrier that houses the projectile
to be fired, not unlike a sabot round fired from a traditional tank.
Some railguns, such as the American naval prototype use a plasma armature, or a thin
metal foil that is placed on the back of the non-conducting projectile.
As the millions of watts flow through the foil it vaporizes and becomes plasma, which
conducts the current.
To fire, the rail gun discharges power from the positive terminal of the power supply
and up the positive rail.
The current then leaps across the armature and down the negative rail and back to the
power supply.
As Michael Faraday taught us, a current flowing through a wire creates a magnetic field, which
has both a magnitude and direction.
The magnitude of this field indicates how powerful the field is, and the direction is
the way the force lines of the magnetic field run.
When the railgun is powered up and the current flows from one rail to the other, the two
rails act like wires with a magnetic field circulating around each rail.
The force lines of the magnetic field run counterclockwise in the positive rail and
clockwise around the negative rail, so the net magnetic field between the rails is directed
vertically.
The projectile between the two rails acts like a charged wire in an electric field,
and experiences a force known as the Lorentz force- named after the Dutch physicist Hendrik
A. Lorentz.
Simply stated, the Lorentz force the projectile experiences is a combination of the electric
and magnetic force due to the two electromagnetic fields.
Because of the alignment of the rails on either side of the projectile, and the direction
of the two magnetic fields, the Lorentz force is thus directed perpendicular to both magnetic
fields and to the direction of the current flowing across the armature.
The Lorentz force is also parallel to the two rails, pushing the projectile away from
the power supply and thus 'firing' it like a cannon shell.
Railgun projectiles are inert, meaning they have no explosive charge whatsoever.
Instead they rely on Isaac Newton's Second Law of Motion: Force = Mass times acceleration.
Basically, the projectile is accelerated to incredible speeds, imparting it with extraordinary
amounts of kinetic energy.
When the projectile reaches its target it then imparts all that kinetic energy to its
target with devastating results.
In fact, rail guns could potentially outdo typical chemical warhead missiles in sheer
destructive potential, as traditional explosives are inherently limited in the amount of energy
they can release by the energy potential of the materials used to create them.
A railgun projectile however can have its kinetic energy, and thus its destructive power,
increased by increasing the speed at which it is fired, with the only limits being the
ability to generate ever greater electrical currents and the projectile's resistance to
disintegrating as it travels through the atmosphere.
So if the railgun is so amazing, and could potentially be even better than missiles in
some scenarios, why isn't one operational yet?
The technical problems remain numerous.
Up until recently the US Navy, in charge of developing the railgun for US ships, was having
problems generating the power sufficient to continuously fire the railgun.
Then as power issues were sorted out and wattages increased, the rails began to experience serious
warping and melting as the Navy tried to reach the Pentagon's requirement that the railgun
fire at a rate of 10 projectiles a minute, eventually only hitting 4.8 rounds a minute
for fear of damaging the delicate rails.
Yet technical problems can and have been largely overcome- minus the rail warping which may
require further investment in materials science to develop conductive materials capable of
withstanding the incredible wattage coursing through it.
The real problem with the US's railgun is one familiar to many ambitious programs around
the world- money.
After ten years and $500 million dollars invested, the Pentagon began to grow dubious about the
railgun's viability.
Rather than further focus efforts on the railgun as a standalone weapon, large amounts of money
were diverted to developing a Hyper Velocity Projectile that used many of the same technological
breakthroughs achieved with the railgun to instead make a new type of cannon shell for
the US Navy's 5-inch guns.
With a speed of Mach 3 and a range of 30 miles (48 km), the HVP will be a huge upgrade to
US guns and easily make them the most powerful naval artillery in the world.
Yet critics of the Pentagon's decision to divert resources from pure railgun research
point out (rightfully so) that a traditional 'powder' projectile will never achieve the
same performance as that offered by the railgun.
While the railgun no doubt offers far greater benefits, the sad reality is that the Pentagon
is currently extremely wary of big, expensive weapons projects after spending billions on
the F-35.
And with Mark 45 5-inch guns already installed on every US ship, the appeal of the Hyper
Velocity Projectile over a futuristic railgun is far greater.
Currently the future of the US's railgun is in serious question, and while most predict
that a railgun will eventually be developed it may come far too late for the US to maintain
its technological advantage over its adversaries.
In fact, just this year China debuted what it claims to be a railgun on one of its frigates
and said it was preparing for sea trials of the new weapon.
While this has alarmed many in Washington, others are wary of the claims and suspicious
that this is nothing more than a hoax meant to intimidate the US Navy, citing serious
technological hurdles that are dubious China overcame so quickly.
But if the Chinese railgun is real this wouldn't be the first time the US and its allies were
surprised by a huge technological breakthrough by an underestimated rival- in the last years
of the Cold War the Soviet Union's development of the Akula class nuclear submarine surprised
every Western observer who did not think the Russians would be capable of building such
a sub for at least ten more years.
More worrisome for Washington, if the Chinese have truly mastered a working rail gun and
will follow through on their stated plans to install them on their ships by 2025, it
could signal the end of the US's absolute dominance of the Pacific ocean and complicate
the strategic picture for regional allies who fear China's South China Sea aggression.
So, will the
railgun ever truly see combat?
Has China really beat the US to the punch, or is it another hoax meant to scare Washington?
Let us know your thoughts in the comments.
Also, be sure to check out our other video Most Successful Weapons Ever Invented.
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See you next time.