2 Flashcards
Usually includes both the engine and the propeller.
- The primary function of the engine is to provide to turn the propeller
powerplant
The power plant converts the _______________________ which creates the
forward motion or thrust.
chemical energy into mechanical energy
An aircraft engine can be categorized into two groups
Reciprocating engines and jet
engines or turbines.
derived from the back and forth or reciprocating
movement of the pistons.
- it is this motion that produces the mechanical energy needed to accomplish work.
reciprocating engine
needed to let the fuel/air into the cylinder.
intake valve
moving within the cylinder, forms one of the walls of the combustion chamber. The piston has rings which seals the gasses in the cylinder, preventing any loss of power around the sides of the piston.
piston
forms a link between the piston and crankshaft.
connecting rod
forms a part of the chamber in which the fuel is compressed and burned.
cylinder
needed to let the exhaust gasses out.
Exhaust valve
aircraft engine also absorbs the power or work from all the cylinders and transfer it into propeller.
crankshaft
The basic principle of reciprocating engine involve the conversion of chemical energy in the form of fuel into mechanical energy. This occurs within the cylinders of the engine. Through a process known as the
four stroke operating cycle
is the position of the piston at the highest point in an engine cylinder
Top dead center or TDC
is the position of the piston at the lowest point in an engine cylinder.
Bottom Dead Center or BDC
begins as the intake valve opens and the fuel and air mixture is drawn into the cylinder. The piston is at the top dead center, moving downward as the piston reaches the bottom dead center intake stroke ends.
Intake Stroke
This stroke begins when the intake valve closes and the piston starts moving upwards to the top dead center while the piston is moving up, it compresses the fuel and air mixture. This phase of the cycle used to obtain a much greater power output from the fuel and air mixture once it is ignited.
Compression Stroke
compressed fuel and air is ignited by the spark plug. This causes a tremendous pressure increase in the cylinder and forces the piston downward away from the cylinder head creating the power that turns the crankshaft. The revolving crankshaft then transfers this energy to the aircraft’s propeller.
Combustion or Power Stroke-
starts when the exhaust valves open, the piston moves upward to purge the cylinder of burned gasses. Once the exhaust valve closes, the intake valve opens and the piston moves down again, repeating this cycle.
Exhaust Stroke-
Jet Engines or turbine
Divided into two section
hot and cold
where the combustion occurs by adding fuel to the airflow provided by the intake of the cold section
hot
brings a free stream of air into the engine. Its focus is to decelerate the incoming air.
INLET
used to** increase the air pressure before it enters the combustor.**
compressor
__________ are the moving parts of the compressor while _______ are the fixed part.
rotors, stators
sits between the compressor and turbine.
Burner or combustion chamber
comparable to a compressor because it is also consist of several rows of rotors, the __________converts thermal energy to kinetic energy by expanding through nozzles then into rotational mechanical energy in a spnning rotor
Turbine-
convert the thermal energy from the exhaust gases into kinetic energy in order to obtain a high exhaust velocity.
nozzle
simplest and the first type of gas turbine engine. Type of engine that generates its thrust by burning a 100% of the air usually used for jet fighters
Turbojet-
provides more efficiency when flying at lower speeds. This engine is** used for some big cargo airplanes.** Best suited for landing and taking off at shorter runways.
Turboprop
most modern variation of the basic gas turbine. Modern airlines used turbofan engines to propel their airplanes through the air. This is due to their higher thrust and fuel efficiency.
Turbofan engine-
has been optimized to **produced shaft power, to drive machinery instead of producing thrust. **Most commonly used in applications that require a small but powerful lightweight engine inclusive of helicopters.
Turboshaft engine
