IEEE Spectrum July, 2007 - 34

The Chinese armor would be one step ahead of such reactive
armor. It uses a sensor to detect incoming shells, and then a coilgun
flings a plate of armor to break up the shell before it hits the tank.
One problem with this approach is that the projectile must be made
of something other than iron, because the coilgun's magnetic pulse
would end up heating the iron rather than accelerating it. Harbin
researchers have tried other materials such as aluminum but found
it melts easily and is too weak for use as armor. In their experiments where steel armor was married to an aluminum coil, "the
thrust force [of the incoming shell] not only didn't decrease but
increased a little," according to a recent paper. [For other electric
gun projects, see sidebar, "Electromagnetic Launch Takes Off."]
Comparable U.S. efforts in electric armor are classified, so
it's noteworthy that even this much is known about the Chinese
program. But for whatever reason, Fair notes, Chinese researchers
are surprisingly open about their work.

the chinese aren't the only ones pushing forward with EM gun

technology these days. The 2006 symposium in Potsdam included
participants from 16 countries, including France, Germany, Iran,
Israel, Italy, Russia, and Sweden.
In the United States, the military's interest in electromagnetic
guns has revived, as has funding, with about $30 million per year
now coming from the Army and the Navy.
The Navy is interested in the technology for its next generation
of all-electric ships. The proposed Sea Strike railgun would launch
tungsten projectiles at a velocity of 2.5 km/s to strike targets on
land or sea up to 500 km away. Moving to electric guns would
mean not having to store gun propellant and explosive ordnance
onboard. Warships rarely sink because of a direct strike from a
bomb or torpedo; rather, the attack causes fuel or munitions to
explode, which then brings down the vessel.
The Army, meanwhile, is focusing on a railgun for a lightweight,
all-electric ground vehicle that would launch kinetic projectiles
against armored vehicles; like the Navy's gun, it would have a muzzle velocity of 2.5 km/s. According to Fair, this speed has been chosen "as a near-term practical limit." While faster projectiles require
expensive nose tips to keep them from melting, relatively inexpengermany, 22 to 25 May 2006,
Had Mccorkle looked further afield, sive nose tips now exist that can withstand the lower speeds.
is the web site http://www.
emlsymposium.org.
he might have run across Wang
Fair's IAT, which saw its budget triple this year to more than
Ying of the Ordnance Engineering $15 million, is now carrying out basic research for both the Army
College, in China's Hebei province. Back in 1981, Ying had come and the Navy. That work includes energy storage and pulsed power,
across the proceedings of Fair's first symposium on EM launch projectile designs that can achieve deeper penetration in their tarand decided to make the subject his life's work. At first, he found gets, improved three-dimensional computer modeling of thermal
few takers for his ideas, but in the last decade, he and his former and stress issues in EM launch, and railgun designs with reduced
students have established electromagnetic launch R&D programs muzzle flash and noise.
at 22 academic and military institutions in China. With Richard
While such efforts may ultimately lead to bigger and better
Marshall, he also coauthored two textbooks on the subject.
guns, the real motivation for many researchers is still Earth-toIndeed, Marshall and Fair were both delighted to find like- space launch. McNab is leading a consortium of the IAT, Texas
minded colleagues in China. In September 2004, Fair's keynote Tech University, the University of Minnesota, and the University
speech at the China EM Launch Symposium, at Dalian University of New Orleans to build a high-altitude railgun for launching
of Technology, drew a standing ovation. Afterward, the head of microsatellites into orbit.
Dalian's electrical engineering department gave him a tour of
As with earlier electric gun projects, though, much about
their coilgun test facility. Today China is arguably the largest this one remains to be worked out. "Both the launcher and the
center of electromagnetic gun research outside the United States. power supplies have yet to be invented that will do this job,"
At the 13th International EML Symposium, held in May 2006 in notes McNab. While integrated electronics that can withstand
Potsdam, Germany, the Chinese accounted for 52 papers, second up to 25 000 g's of acceleration have been successfully tested,
only to the United States, which had 72.
hardening them to about 65 000 g's may be needed.
One intriguing Chinese project is the coilgun-based armor
Fair, though, remains undaunted. "We're now just past the tipunder development at Harbin Institute of Technology. Tank ping point," he says. Just as sailing ships gave way to steamboats
armor today consists of a thin layer of high explosive sandwiched and piston-driven prop planes were eclipsed by jet aircraft, he says,
between two metal plates; when hit, it erupts, thereby destroying chemical propulsion will eventually cede to electromagnetic guns.
conventional weapons such as shaped charges.
"It's inevitable."
n

46 IEEE Spectrum | July 2007 | NA

www.spectrum.ieee.org

mance in the most distant foreseeable future" [emphasis in original].
Another IAT researcher recalls that in meetings McCorkle would
pull out a calculator, ostensibly to produce numbers that proved
EML's inefficacy; but those numbers, the researcher contends, were
"by and large, quite incorrect. In every issue raised, he has been
rebutted by real calculations or a more sober statement of facts."
McCorkle now acknowledges making mistakes. "The calculations are really much too complex to do by hand," he told Spectrum
in an interview last year, adding that the errors still don't affect
his conclusions. "There are some simple relationships, for example,
between the number of megajoules required and the ratio of input
power to output power." He argued that the waste heat produced
by the guns in itself is enough of a problem to make rapid-fire
EM guns impossible. He also charged that the researchers "abuse
classification" to hide their failures.
Much of the work on EM guns in the United States is indeed
classified, admits Ian McNab, an expert on pulsed power sources
at IAT. But, he points out, "we don't classify anything; the Army
classifies them. The Army has this
idea that we should be doing this
ABouT ThE AuThor
research for them, not the Chinese."
CArolyN MEINEl is a science
writer and IEEE member
He counters McCorkle's other conbased in Sandia Park, N.M.
tentions by saying, simply: "We've
She has consulted on electrobuilt these things, and they work."
magnetic gun technologies
One of McCorkle's arguments,
for SAIC (Science Applications International Corp.),
though, seemed valid: if EM guns
the Institute for Advanced
were so great, why was there so litTechnology, and DArPA.
tle research going on elsewhere? The
British program, he argued, was an
artifact of an EM gun given to them
To ProBE furThEr
IEEE Transactions on
by the U.S. Defense Department. "I
Magnetics has published
have also talked to the Germans and
proceedings from the
discovered their interest was based
Electromagnetic launch
upon their belief that the U.S. someSymposium since the first
meeting in 1980. Another
how had a 'secret breakthrough'...
source of papers from the
otherwise it made no sense to them,"
13th International EMl
he
wrote in his letter to Fair.
Symposium, held in Potsdam,

http://www http://www.emlsymposium.org http://www.spectrum.ieee.org

Table of Contents for the Digital Edition of IEEE Spectrum July, 2007