Armament Section

The armament system contains the payload (explosives), fuzing, safety and arming (S&A) devices, and target-detecting devices (TDDs).

PAYLOAD.- The payload is the element or part of the missile that does what a particular missile is launched to do. The payload is usually considered the explosive charge, and is carried in the warhead of the missile. High-explosive warheads used in air-to-air guided missiles contain a rather small explosive charge, generally 10 to 18 pounds of H-6, HBX, or PBX high explosives. The payload contained in high-explosive warheads used in air-to-surface guided missiles varies widely, even within specific missile types, depending on the specific mission. Large payloads, ranging up to 450 _{pounds, are common.} Comp B and H-6 are typical explosives used in a payload.

Most exercise warheads used with guided missiles are pyrotechnic signaling devices. They signal fuze functioning by a brilliant flash, by smoke, or both. Exercise warheads frequently contain high explosives, which vary from live fuzes and boosters to self-destruct charges that can contain as much as 5 pounds of high explosive.

FUZING.- The fuzing and firing system is normally located in or next to the missile's warhead section. It includes those devices and arrangements that cause the missile's payload to function in proper relation to the target. The system consists of a fuze, a safety and arming (S&A) device, a target-detecting device (TDD), or a combination of these devices.

There are two general types of fuzes used in guided missiles-proximity fuzes and contact fuzes. Both fuzes are armed by acceleration forces upon missile launching. Arming is usually delayed until the fuze is subjected to a given level of accelerating force for a specified amount of time. In the contact fuze, the force of impact closes a firing switch within the fuze to complete the firing circuit, detonating the warhead. Where proximity fuzing is used, the firing action is very similar to the action of proximity fuzes used with bombs and rockets.

SAFETY AND ARMING (S&A) DEVICES.- S&A devices are electromechanical, explosive control devices. They maintain the explosive train of a fuzing system in a safe (unaligned) condition until certain requirements of acceleration are met after the missile is fired.

TARGET-DETECTING DEVICES (TDD).-

TDDs are electronic detecting devices similar to the detecting systems in VT fuzes. They detect the presence of a target and determine the moment of firing. When subjected to the proper target influence, both as to magnitude and change rate, the device sends an electrical impulse to trigger the firing systems. The firing systems then act to fire an associated S&A device to initiate detonation of the warhead.

Air-to-air guided missiles are normally fuzed for a proximity burst by using a TDD with an S&A device. In some cases, a contact fuze maybe used as a backup. Air-to-surface guided missile fuzing consists of influence (proximity) and/or contact fuzes. Multifuzing is common in these missiles.

Propulsion Section

Guided missiles use some form of jet power for propulsion. There are two basic types of jet propulsion power plants used in missile propulsion systems-the atmospheric (air-breathing) jet and the thermal jet propulsion systems. The basic difference between the two systems is that the atmospheric jet engine depends on the atmosphere to supply the oxygen necessary to start and sustain burning of the fuel. The thermal jet engine operates independently of the atmosphere by starting and sustaining combustion with its own supply of oxygen contained within the missile.

ATMOSPHERIC JET PROPULSION SYSTEM.- There are three types of atmospheric jet propulsion systems-the turbojet, pulsejet, and ramjet engines. Of these three systems, only the turbojet engine is currently being used in Navy air-launched ^missiles. A typical turbojet engine includes an air intake, a mechanical compressor driven by a turbine, a combustion chamber, and an exhaust nozzle. The engine does not require boosting and can begin operation at zero acceleration.