Engine Components
In which engine component does the air-fuel mixture burn?
Cylinder
Which valve allows the air-fuel mixture to enter the cylinder?
Intake valve
What device ignites the fuel mixture?
Spark plug
Which engine type has rotating cylinders and a stationary crankshaft?
Rotary engines
What is the most common engine arrangement used in general aviation aircraft today?
Horizontally Opposed Engines
Which engine part directly converts the force of combustion into mechanical motion?
Piston
Which valve opens to release burned gases after combustion?
Exhaust valve
Why do most aircraft engines use two spark plugs per cylinder?
Improved reliability and more complete combustion
Which engine type has stationary cylinders and a rotating crankshaft?
Radial engines
How are the cylinders arranged in an in-line engine?
In a single row from front to back
Which component allows the piston’s up-and-down motion to be transferred to the crankshaft?
Connecting rod
During which part of engine operation must both valves be closed?
Combustion
Why must the spark occur before the piston reaches Top Dead Center? (TDC)
Because fuel takes time to burn completely
Which engine type was commonly used during World War I?
Rotary Engine
How are cylinders arranged in a horizontally opposed engine?
Two flat banks directly opposite each other
Which two engine components work together to convert reciprocating motion into rotary motion?
Connecting rod and crankshaft
Why must the intake valve close before the fuel-air mixture is ignited?
To seal the cylinder so pressure can build during combustion
What is the role of the distributor in a multi-cylinder engine?
To deliver spark to each cylinder at the correct time
Why did the rotating mass of a rotary engine affect aircraft handling?
Gyroscopic forces interfered with turning
Why does the flat shape of a horizontally opposed engine reduce form drag?
There is less air resistance
If the camshaft stopped turning but the crankshaft continued to rotate, which engine function would fail?
Valve operation (intake and exhaust opening and closing)
What would happen to engine power if the exhaust valve opened too early?
Loss of pressure and reduced engine power
Why does an engine with independent ignition systems continue running if one system fails?
Each cylinder has its own timing and spark delivery system?
Based on design alone, why were radial engines more suitable than rotary engines for larger aircraft?
Radial engines avoided heavy rotating cylinder mass while still allowing many cylinders
Why did horizontally opposed engines replace in-line engines in most small aircraft?
Reduced form drag and improved aerodynamic efficiency