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. Thanks for watching, and as always, don’t
forget to like, share and subscribe. See you next time.
