Engines & Ignition Flashcards
What are the key components of piston engines?
Cylinder, piston, connecting rod, and piston rings.
What is the role of piston rings in an engine?
To create a seal and maintain compression.
What are the four strokes in a four-stroke engine cycle?
Intake, compression, power, and exhaust.
How does the camshaft control valve operations?
By opening and closing valves through push rods and rocker arms.
What is the difference between fixed pitch and constant speed propellers?
Fixed pitch propellers have a set blade angle; constant speed propellers adjust blade angle for efficiency.
What are common methods of engine cooling in piston engines?
Oil cooling and air cooling.
Why is pre-flight inspection critical for aircraft engines?
To check for contamination, damage, engine oil levels, and overall condition.
What is the purpose of the fuselage in an aircraft?
To provide structural integrity and house components like bulkheads, stringers, and skin.
What are the types of undercarriage configurations?
Tricycle and tailwheel configurations.
What is the role of the propeller twist?
To create equal thrust along the blade.
What is the role of magnetos in the ignition system?
To generate electrical current for spark plugs independently of the battery.
What is the purpose of the rocker arms in an engine?
To transfer motion from push rods to open or close engine valves.
What is the compression ratio, and why is it important?
It is the ratio of total volume to clearance volume in an engine cylinder, affecting engine performance and efficiency.
What causes detonation in aircraft engines?
Low octane fuel, high compression, lean mixtures, or overheated engines.
How can detonation in engines be prevented?
Use higher octane fuel, avoid lean mixtures, and monitor engine temperatures.
What is pre-ignition, and what causes it?
Pre-ignition occurs when the fuel-air mixture ignites before the spark plug fires, caused by hot spots or overly lean mixtures.
What is the modified Otto cycle?
A cycle with adjustments to valve timing and ignition to enhance engine power.
What is valve overlap, and why is it important?
A short period when both inlet and exhaust valves are open, improving engine efficiency.
What is volumetric efficiency in engines?
It measures the efficiency of filling the cylinder with the fuel-air mixture; can exceed 100% in turbocharged or supercharged engines.
What happens during the ignition and power stroke in an engine?
The spark plug ignites the fuel-air mixture, driving the piston downward and rotating the crankshaft.
What are the effects of detonation on engine components?
Causes piston damage, increases cylinder head temperature, and reduces engine performance.
What role do spark advance and effective crank angle play in engine operation?
Spark advance maximizes piston momentum, while effective crank angle transmits power to the crankshaft.
What is the difference between detonation and pre-ignition?
Detonation is an uncontrolled explosion after the spark plug fires; pre-ignition occurs when the mixture ignites before the spark plug fires.
What are the advantages of fuel injection systems over carburetors?
More efficient fuel burn, reduced induction icing, consistent power output, and better fuel atomization.