A super-high-velocity gun, operating on electrical energy instead of an explosive
propellant, has been a minor scientific dream for some time. The idea is not new;
for it was tried by the French in World War I. But in World War II, a German scientist
felt he was so close to a solution of the problems involved that the German Air Force
had contracted for an experimental electric gun. This gun was to be capable of
ejecting a 40-mm projectile at a muzzle velocity of 6,600 feet per second—far
above the velocity of any shell yet fired from a conventional artillery piece.
Although the gun ordered was not delivered before the end of the war, a miniature that
actually worked was built and tested. Theoretical calculations, based upon tests made
with the miniature gun, led the German scientists to believe it possible to build an
electric gun capable of tossing a 14-pound projectile to an altitude of 12 miles
in 13 seconds.
To men familiar with the problems of antiaircraft artillery, such a weapon appeared a
godsend. The 90-mm antiaircraft gun of conventional, powder-burning design, can reach
only 4.4 miles in altitude in the same length of time.
Although the problem of electrically ejected shells is an old one, it has still to pass
the research stages. The chief problem is to obtain a source of sufficient electrical
power that will not be all out of proportion to the size of the gun. Designing a gun
did not seem to be too great a problem, for the German model appeared logical.
The German gun, had it ever been built to full scale, would have had a rectangular barrel
33.7 feet long. The round bore, as designed by the Germans, is flanked by two, square
grooves 180 degrees apart, so that when the bore is seen from one end, it is the same shape
as the aircraft identification insignia used by the U.S. Army Air Forces. The bore is not
rifled. At the extreme ends of the two grooves, an insulated, copper glide rail runs
the entire length of the barrel. It is through these glide rails that the electrical
energy is conducted for ejecting the shell.
Diagrammatic sketch of the electric gun projectile (left) and its glide wing,
and (right, top to bottom) end view of the projectile, isometric view of the gun tube, and end
view of the tube showing the shape of the bore and the position of the copper
gliderails through which the propelling electric charge is passed.
The shell is a cylindrical projectile somewhat longer than the conventional
artillery shell, and has four narrow fins at its base. It is fitted with a cradle,
called a "glide wing," from which extend two studs which fit into the square grooves
of the bore, and ride on the copper glide rails. After the shell has been placed in
the gun, a jolt of electricity is shot into the weapon. The current, passing along
the glide rails and through the glide wing, sets up an intense magnetic field. The
reaction is such that the magnetic field and the current flow through the glide
rails tend to repel each other. This, in effect, forces the projectile up the bore
at an ever increasing velocity until, when it leaves the muzzle, it is traveling at
a terrific rate of speed. This reaction is so fast that it is only a matter of a
split second between the introduction of the current and the ejection of the shell
from the gun.
It is the opinion of some scientists that the electric gun deserves further study
and experimentation, since it contains, in theory at least, some marked advantages
over the conventional antiaircraft artillery of the present day. It is theoretically
capable of obtaining muzzle velocities far in excess of what to date has appeared
possible for powder-burning weapons. It is noiseless, smokeless, and has no
flash. Constructed of materials easily obtainable, it requires comparatively
little high-precision machining. Unlike other artillery pieces, the machined
surfaces are not subjected to high pressures and intense heat. Moving parts are
few, and these can be greased. Recoil is negligible, and range can be adjusted by
varying the electric current. The gun has a high efficiency, compared to ordinary
pieces, since there is no energy wasted through heat and escaping gases, and the
manufacture and handling of cartridges is eliminated. But perhaps most important
is the fact that ranges and penetrating power now unattainable may be reached in
the electric gun.
Of course, these advantages are in turn offset by the chief problem—power
supply—and a myriad of minor electrical wrinkles that would require
straightening before a truly efficient gun could be produced. It is one thing to
handle large amperages in a power house, and quite another to supply them to, and
use them in, a comparatively small piece of machinery which, to be of full military
value, must retain the essentials of mobility.