Aircraft require thrust to produce enough speed for the wings to provide lift or enough thrust to overcome the weight of the aircraft for vertical takeoff. For an aircraft to remain in level flight, thrust must be provided that is equal to and in the opposite direction of the aircraft drag. This thrust, or propulsive force, is provided by a suitable type of aircraft heat engine. All heat engines have in common the ability to convert heat energy into mechanical energy by the flow of some fluid mass (generally air) through the engine. In all cases, the heat energy is released at a point in the cycle where the working pressure is high relative to atmospheric pressure.
“PROPULSION”, the word is derived from two Latin words: pro meaning before or forwards and pellere meaning to drive. Propulsion means to push forward or drive an object forward. A propulsion system is a machine that produces thrust to push an object forward. On airplanes and spacecraft, thrust is generated through some application of Newton’s third law of action and reaction. A gas, or working fluid, is accelerated by the engine, and the reaction to this acceleration produces a force on the engine. The amount of thrust generated depends on the mass flow through the engine and the exit velocity of the gas. Different propulsion systems generate thrust in slightly different ways.
- General Requirements
- Types of Engines
- Reciprocating Engines
- Crankshafts
- Connecting Rods
- Pistons
- Piston Rings
- Cylinders
- Firing Order
- Valves
- Valve Operating Mechanism
- Bearings
- Propeller Reduction Gearing and Propeller Shafts
- Reciprocating Engine Operating Principles
- Operating Cycles
- Reciprocating Engine Power
- Reciprocating Engine Efficiencies
- Gas Turbine Engines Types and Construction
- Air Entrance
- Accessory Section
- Compressor Section
- Diffuser
- Combustion Section
- Turbine Section
- Exhaust Section
- Gas Turbine Engine Bearings and Seals
- Turbine Engine Operating Principles
- Thrust
- Gas Turbine Engine Performance