Systems of classification of rockets and missiles

MISSILES AND ROCKETS

PRINCIPLE OF OPERATION

Numerous types of designs of missiles and rockets have been developed for use against various types of targets. Differ as these designs do all of them have in common at least one characteristic: the principle upon which their engines operate is Isaac Newton’s third law of motion: “Every action has an equal and opposite reaction.”

The “action” in a rocket engine is the pressure exerted by flaming gases when the propellant, either solid or liquid, is ignited in the firing chamber. The “reaction” is the way the chamber that encloses the gases responds to this action.

As shown in Fig. I, when the ignited gases in the chamber press the enclosing surfaces looking for an escape, there is only one escape – through the open end called the discharge nozzle.

Pushing against the closed end, the hot gases build up pressure that thrusts the rocket forward while the gases are ejected through the discharge nozzle, just as a cannon recoils from its powder charge or as a blown-up balloon reacts when released and the air escapes. The resultant forward thrust is the “reaction” which gives its power.

SYSTEMS OF CLASSIFICATION OF ROCKETS AND MISSILES

There are in existence a number of classification principles for the rocket engines and the rockets proper (the vehicles). The more general ones will be described below.

The rocket engines are divided into two main classes – the solid propellant engines and the liquid propellant engines. In the solid propellant engine, all the fuel is contained in a high pressure combustion chamber. Once the propellant is ignited, the rate of combustion cannot be controlled nor can it be stopped and refined.

In the liquid propellant rocket engines, the fuel and oxidizer are carried in thanks, and a feed system is used to force the propellant into the combustion chamber. The rate of combustion in this type of engine can be controlled by the feed system.

The rockets proper (the vehicles) are divided into two main classes – the “free” (nonguided) rockets termed “rockets” and the “guided” rockets “missiles.”

Free rockets do not contain any guidance mechanism. The launcher imparts initial direction to the rocket, which then follows a normal ballistic trajectory to the target. Free rockets are characterized by the great weight of ammunition, relatively light weight of launcher, and decrease in accuracy as compared with artillery cannon as shorter ranges.

As opposed to free rockets, missiles are vehicles which move above the earth’s surface and whose trajectory or light path can be altered by a mechanism within the vehicle. Radar, television, heat, or number of other agencies may be adapted to move the steering mechanism of missile to direct it on a collision course. Or it may be steered to its target by remote control by means of radio signals.

The type of frame construction furnishes another principle for classification of rockets and missiles. In accordance with this principle all rockets and missiles are divided into the winged and the unwinged groups. The aerodynamics of the winged rocket is similar to that of the airplane, i.e., its flight is determined by the lifting force of the wings. The unwinged rockets and missiles are often called ballistic for they usually follow a ballistic trajectory.

According to their combat missions all missiles and rockets of the US Armed Forces are designated as Strategic Missiles, Tactical Missiles, Air/ Space Delense Missiles and Antisubmarine Missiles. The strategic missiles are subdivide into intercontinental ballistic missiles (ICBM) and intermediate range ballistic missiles (IRBM), while the tactical missiles include such subcategories as antitank missiles and anti-low-flying aircraft missiles; the are space defense missiles include antiaircraft and antimissiles systems. Missiles designed to penetrate enemy defenses or launched upon approaching targets for diversionary purposes are called “diversionary” missiles. Missiles used to hamper the operation of radar installations are termed “antiradar” missiles. The relative location of the missiles launcher (or the launcher pad) and the target provides the basis for dividing the missiles and rockets into several general categories (or types). In the US Armed Forces there are four of them: surface-to-surface, surface-to-air, air-to-air and air-to-surface.

The surface-to-surface missile is equivalent to long range artillery that may be fired from land against troop concentrations, important supply depots, communication centers, or industrial areas.

Under the “US Army policy for the integration of rockers and missiles into the Army weapons system”, surface-to-surface missiles are defined by three ranges.

Short-range – assault or demolition guided missiles to be used armor and fortifications; medium-range – missiles to supplement and extend the or firepower of artillery cannon, to provide close or interdiction fire support for ground combat forces, and to compensate for the expanding dimensions of the battle area; long-range – missiles capable of supporting deep penetrations, or airheads, from protected and widely dispersed rear; and of delivering accurate fire on distant targets which are capable of affecting the execution of the Army’s combat mission.

The surface-to-air missile is analogous to an antiaircraft shell but is far more lethal and has far greater speed, range, and accuracy. These missiles are effective in destroying high-speed airplanes at al altitudes.

The air-to-air missile is the principal weapon of air-to-air combat. The speed of jet fighters gives them both an offensive advantage over the larger and slower strategic bombers that they may attack. However, if bombers are armed with missiles that, when launched, automatically steer themselves toward the attacking fighter and explode at contact or in close vicinity, then they have an effective defense against the faster attacking plane.

The air-to-surface missiles are, in affect, a type of controlled bomb. They are very effective against special kinds of ground targets, bridges, ships, etc.

To characterize a rocket or missile fully all the above mentioned principles of classification must be applied. In other words one has to state whether the rocket (missile) is equipped with a solid or a liquid propellant engine, whether the rocket is guided or free, whether the frame is winged or wingless, what the category of the rocket is and what type of mission it fulfills.

Дата добавления: 2015-11-14