August 30, 2007: The U.S. Navy is developing a new
bomb for clearing obstacles and mines off a beach, or any other patch of
terrain. Called the JABS, (JDAM Assault Breaching Systems) the bomb uses the same design as many
air-to-air missile warheads. This is known as the continuous rod warhead, and
when built into a 500 or thousand pound bomb, was tested and found capable of
obliterating concrete blocks and steel obstacles, and setting off any mines
within many meters of the explosion.
The continuous rod warhead is a clever concept
(developed by the U.S. Navy in the early 1970s) which is built by first
arranging an even number of individual steel rods on a cylindrical form (that
is slightly smaller than the diameter of the missile the warhead will be
mounted on.) The rods are parallel to the axis of the form and completely cover
it. Then, at the ends, every other rod
is welded to the adjacent rod. On the opposite end, the same thing is done,
although the first pair of rods are not
welded on the opposite end. Next, the
cylinder of rods is covered with a light sheet metal jacket that will serve to
hold all rods in place. The form is removed and replaced with explosives in a
similar shape.
When this warhead detonates, the high explosive
propels the rods outward at high speed, in an expanding circle. The detonation
does not break the welded joints, but they do bend. When the chain of welded
rods expands as far as it can, some of the welds do break and the rods, individually
or two or three still connected by the welds, will continue moving until they
rip into something, or lose momentum and fall to the ground. The rapidly
expanding ring of rods does a lot more damage to anything it hits than would be
the case with conventional shell fragments. Any part of the aircraft hit by the
rods experiences an effect similar to a knife slicing through the aircraft.
Cables, wires and hydraulic lines are cut and massive damage inflicted.
Such warheads can be made even more lethal by
having two or more layers of welded rods. This increases the effective range of
the warhead. The JABS has several layers of steel rods, and lots of explosives.
It's estimated that a hundred half-ton JABS could clear a lane, 50 meters by
200 meters, through concrete and steel obstacles, as well as setting off all
mines. Because the bombs are GPS guided, accuracy is not a problem. That many
bombs could be delivered by two B-52s (or other heavy bombers), or a dozen
F-18s.
