A continuous-rod warhead is a specialized munition used as part of an anti-aircraft missile.
Construction
In its most simple conception, consider a cylindrical form upon which an even number individual steel rods are arranged. The rods are parallel to the axis of the form and completely cover it. Now at one end, weld every other rod to the adjacent rod. On the opposite end, likewise weld the rods in pairs but ensure when starting that the first pair of rods is not welded on the opposite end. When all rods are welded, the cylinder of rods may be covered with a light sheet metal jacket that will serve to hold all rods in place. The form may now be removed and in its place is cast a cylinder of high explosive.
Operation
When detonated, the high explosive imparts a momentum to the rods, thrusting them outward in an expanding circle. The rods are sufficiently ductile to allow the expansion without breaking the welded joints, the rods instead bending at these points.
The effect is to produce a quickly moving and expanding ring of continuous rod. The effect of this expanding ring upon contact with an aircraft is much more devastating than the conventional shrapnel used in earlier weapons. It is almost assured that any portion of the aircraft intercepted by the expanding ring will be completely dissected, including wiring, fiber optics, cables, and hydraulic lines, no matter how redundant they are. This assurance applies only as long as the ring is unbroken, so multiple layers of rods are employed in practical weapons to increase the effective radius.
Deployment
The warhead is a major component of an anti-aircraft missile — 10 to 15 percent of its overall length. It is preceded by a guidance system and is followed by a rocket motor. Directional vanes or wings are positioned relative to the warhead as is appropriate to the weight distribution and aerodynamics of the particular missile. These vanes or wings are attached to and moved by a control system component under the direction of the guidance portion.
Employment
To be effective the detonation must occur sufficiently close to the target aircraft, so this type of warhead is used in only in precision radar guided missiles such as the AIM-7 Sparrow. Other missile types such as the heat seeking AIM-9 Sidewinder will fly to and contact a heat source such as the tailpipe of a jet engine and so detonate sufficiently close to (or within) the aircraft as to allow the effective use of a simple high explosive or fragmentation type warhead.