31-03-2017, 03:19 PM
Thermal jet engines
The missiles with thermal jet engines "breathe" in a predetermined amount of air and compress it. The liquid fuel is then injected into the compressed air and the mixture is ignited. The combustion takes place inside a combustion chamber. The resulting hot gases are expelled through an exhaust nozzle at the rear of the missile. At this point, the heat energy is transformed into kinetic energy and the thrust or propellant movement is created. An air-breathing jet engine must rely on the oxygen obtained from the atmosphere for fuel combustion to occur. That is a disadvantage because the flight altitude (or ceiling) of the missile is thus limited. However, at low altitudes, the jet engine (thermal) is very efficient.
Rocket Engines
A rocket motor (jet) does not depend on the air intake for its operation. It is therefore capable of operating at very high altitudes and even beyond the atmosphere. A rocket motor carries within it all the materials required for combustion. That usually includes a fuel, either solid or liquid, and an oxidant. The oxidant is a substance capable of releasing the oxygen that is necessary to withstand combustion. Once the rocket motor propeller ignites, the hot gases are expelled from the exhaust nozzle. The heat energy is changed to kinetic energy and the thrust is created. The amount of thrust developed by a rocket-type engine is generally considered extremely high compared to the thrust of a similarly sized breathing air motor.