American Projectiles and Explosives
One of the newest trends [c.1947] in American ordnance development, guided missiles became service items in the last months of World War II. Guidance was applied to modified bombs, winged glide bombs, and standard aircraft, and in jet- and rocket-propelled airframes.
Guided missiles have great range, high payload capacity, and extreme accuracy; and their progress in designed has proceeded so rapidly that on only a few items has the design become standardized or "frozen". All the missiles included here were at least in the testing stage and were being pursued as active projects at the time of writing. Furthermore, only those missiles designed for combat or military purposes - none of the basic research items - are included; and, of these, only their ordnance components can be described in detail.
American missiles are usually guided by remote radio control, the receiver in the missile acting through servo units to position the air foils.
The person controlling the flight of the missile will guide its path on the basis of information obtained visually, through a television receiver, or by ordinary radar tracking. Some missiles have automatic guidance features, of such a nature that, once the target has been "shown" to the missile's intelligence unit, it will automatically "home on" to its destination unassisted.
Depending on the particular item, a missile may be powered by gravity, aircraft, engines, JATO units, rocket motors, or jet motors.
Thus far, guided missiles have adapted standard bombs as their explosive payloads. Fuzing of these bombs differs from the standard fuzes in that the fuzes must be made in an elbow shape, in order to fit in the fuze pockets and, at the same time, permit vane arming.
For the Navy, the Bureau of Ordnance and the Bureau of Aeronautics are developing guided missiles; for the Army, the Air Forces are in charge of the program.
Bureau of Ordnance Missiles
1,200-pound "Dove" Bomb Mk 64 (Air-to-Surface Missile)
Overall length: 84.5 inches
Overall diameter: 18.75 inches
Weight of intelligence units and special tail: 183 pounds
Warhead (1,000-pound G.P. Bomb AN-M65): 975 pounds
Total weight: 1,160 pounds
General: The Bomb Mk 64 is an experimental heat-homing bomb, consisting of a detecting, computing, and guiding mechanism housed in a nose attachment fitted on the 1,000-pound G.P. Bomb AN-M65. It is designed for attack on maneuvering targets and is effectively employed in both high-angle and dive-bombing runs against objects which have sufficient thermal contrast to their background.
"Dove" is designed to fit the normal plane stowage, but carrying capacity is sometimes reduced because of the missile's increased length. The special Bomb Fin Mk 1 is a box-kite shape and eight inches longer than the standard tail for this bomb.
Control: Aerodynamic control is effected in range and azimuth by means of four movable nose deflectors independently controlled, which thus form quadrants of a cylindrical surface whose axis is parallel to that of the bomb. The deflectors may be extended a maximum distance of 4 and 1/2 inches. The movement of the deflectors is determined by the intelligence unit, which consists of the heat-detecting eye, gyro system, auxiliary electronic relays, servo motors, and battery.
1,600-pound "Bat" S.W.O.D. Mk 9 (Air-to-Surface Missile)
Overall length: 11.9 inches
Wing span: 10 feet
Total weight: 1,600 pounds
Warhead: 1,000-pound G.P. Bomb AN-M65
General: S.W.O.D. (Special Weapons Ordnance Device) Mk 9, or "Bat", is a glide bomb equipped with a radar homing set mounted in the nose. It is designed primarily for attacking marine targets, and is effective for night or day attacks upon shipping in any weather in which the parent plane can fly. The launching planes need not stay in the vicinity of the target, and may release as many as four of these missiles in salvo.
The airframe consists of plywood sections which are fitted around the Bomb AN-M65. Control surfaces consists of an elevon on each wing which can be moved to control pitch or bank. There are no control surfaces on the tail.
To ensure destruction of the intelligence system, the Demolition System Mk 122 is used.
Installation of the Fuzes Mk 235 and Mk 236, with their outside windmills and flexible arming stems, is standard.
Control: This missile has its own radar transmitter and receiver. When the target is located on the scope of the monitor unit in the plane, it is put into the range step of the missile's scope and is automatically kept there. At the correct instant, determined by a glide ratio scale, the missile is released and is guided to its target by the radar signal in its own scope. The guiding radar supplies corrections to the servo system, which is also controlled by a gyro pilot, the device which maintains flight attitude.
Suspension: Standard bomb lugs are employed on the airframe. Also, there is the multi-conductor cable connecting the missile's radar with the monitor set in the plane, known as the umbilical cord.
Demolition System: This destructor assembly consists of the S-122-11G switch, Junction Box Mk 1 Mod 0, primacord connectors, and ten Demolition Charges Mk 4. The S-122-11G switch incorporates an inertia weight, held by a spring tension of 11G, which will topple if that force is exceeded in an impact. When this inertia weight topples (it is mounted on a universal pivot) the contact bar, which has been transmitting the spring tension to the inertia weight, rotates because of the spring load and completes the electrical circuit across the contacts. This switch has an arming stem, connected to windmill vanes mounted on the outside of the missile fuselage, which unscrews to arm the switch. These vanes have an arming wire to prevent rotation before release from the parent aircraft. On one side of the switch is a clear plastic inspection port. Tension on the spring is pre-set at 11g when the switch is assembled at the factory.
When the switch completes the circuit, current from the battery sets off the electric blasting cap in the junction box, which fires the primacord connectors and then the TNT blocks, placed around the intelligence unit.
Remarks: The S.W.O.D. Mk 9 is commonly known as "the 1,000-pound Bat". The S.W.O.D. Mk 10, built around a 2,000-pound bomb is not being actively developed, because it is felt that the 1,000-pound size is large enough for currently projected use.
Next Time: Bureau of Aeronautics Missiles