Aircraft engine

Aircraft Propulsion is a collective term for the engines used for propulsion generation of aircraft. If necessary, propeller and gear to be accounted for, which, although not serve the actual power production, but the propulsion development. This technical system allows the aircraft to obtain the ( propulsion ) power to actively lift off the ground to independently gain height and to move forward in the airspace.

For civil aircraft, the concept of the drive system (English Propulsion System) is to be distinguished, which can be called from an existing engine, engine cowling and thrust reverser assembly.

Historical Development

After the development of non-powered gliders (especially by Otto Lilienthal ) was the main problem for lasting haul that weight force prevented the holding of the altitude. The energy required to overcome the force of gravity could not be provided. The first steps consisted by heated air or gases to utilize the buoyancy ( Montgolfier and balloon). Updrafts were and are used by gliders. Only with the availability of lightweight, high-performance active aircraft engines were also the aircraft that were heavier than air to independently rise into the air, gain height on its own and fly distances without losing height.

Drive types

There have now been developed a variety of actuators for aircraft. There are up to now mainly internal combustion machines. They are divided into two groups:

• Breathing air drives; the drive applies the necessary oxygen for combustion of the fuel from the ambient air. " Aircraft engine ": a piston engine than gasoline or diesel engine. A reciprocating engine provides the shaft power that drives a propeller. Construction methods are radial engine, in-line engine, Boxer engine.
• Gas turbine engines The Turbojet is a pure jet engine: The compressor of the turbo - jet engine compresses the air sucked. In the combustion chamber it is then burned with kerosene, being strongly heated and accelerated. The subsequent turbine cut off the exhaust jet some energy in order to drive the compressor located at the inlet. The remaining exhaust jet energy is the propulsion.
• The turbofan is largely the same structure as the Turbojet. In addition, the turbine drives the compressor even before big " fan" blades at which similar to a propeller speed to the rear a large amount of air " at the actual engine over." The major part of the driving power usually attributable to this sheath flow, the gas turbine exhaust gas stream, however, is negligible. Often, therefore, only the sheath flow is diverted to the thrust reversal.
• Turboshaft engine ( turboprop ) for driving a propeller: A turbojet engine whose thrust is negligible, but decreased its power development on the drive shaft and transferred to a propeller (usually via a gear ).

• Rocket motor: in the rocket engine, the combustion usually leads of two chemicals excessive expansion, which is directed through a nozzle. The support mass spreads out in the appropriate direction, the reactions drives the missile in the opposite direction.

Other species have been driving only minor importance:

• Electric motor with propeller: The energy for the electric motor comes from a battery, a fuel cell or rare solar cells ( solar plane ).
• Tretpedale or mechanical energy storage with Propeller: Only for model aircraft are on the ground rubber twisted, then the self- untwisting turn a propeller and generate propulsion. Fired with ( human ) muscle strength aircraft are Musculair 1 and 2 (see also muscle strength aircraft ).
• Propulsion by means of wings: wings aircraft ( ornithopter ) there are only in the experimental area or in the model, the actual driving force produces an electric motor or internal combustion engine.

Problem areas

Due to the altitude and low air pressure associated results in technical difficulties to supply the motors with enough oxygen from the ambient air, especially in piston engines. One way to compensate for the lower air density at piston engines is the engine charging. Also gas turbines show high-altitude performance degradation, but to a lesser extent, since the efficiency increases in colder air.