Reciprocating Construction
A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is
hydraulic lock
The five events of a four-stroke cycle engine in the order of their occurrence are
intake, compression, ignition, power, and exhaust.
Some cylinder barrels are case hardened by
Nitriding
What is the purpose of installing two or more springs on each valve in an aircraft engine?
To eliminate valve spring vibration or surging.
An aircraft engine has 9 cylinders. From this information alone we can deduce that
A. it contains both master and articulating rods.
B. its firing order is 1-3-5-7-9-2-4-6-8.
C. it is water cooled.
its firing order is 1-3-5-7-9-2-4-6-8.
The ratio of the weight of the fuel/air charge taken into the cylinder, to the weight of a charge that would completely fill the entire volume of the cylinder at the same pressure
What is volumetric efficiency
If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed
just after top center at the beginning of the power stroke.
On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?
Near the top of the cylinder.
Why does the smoothness of operation of an engine increase with a greater number of cylinders?
The power impulses are spaced closer together.
Cam ground pistons are installed in some aircraft engines to
provide a better fit at operating temperatures
Which bearing is least likely to be a roller or ball bearing?
Master rod bearing (radial engine).
On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?
Exhaust and intake.
What is the purpose of the safety circlet installed on some valve stems?
To prevent valves from falling into the combustion chamber.
Compression ratio is the ratio between the
cylinder volume with piston at bottom dead center and at top dead center
Which is the typical firing order on an 4 cylinder opposed aircraft engine?
opposed cylinders from rear to front
opposed cylinder from front to rear
opposed cylinder and oppoed diagonally
Opposed cylinders from the rear to the front
The operating temperature valve clearance of a radial engine as compared to cold valve clearance is:
Greater.
Less
The same
Greater
The actual power delivered to the propeller of an aircraft engine is called
Brake Horsepower
Full-floating piston pins are those which allow motion between the pin and
both the piston and the small end of the connecting rod.
What will be the likely result if the piston ring gaps happen to be aligned when performing a differential pressure compression check on a cylinder?
A worn or defective ring(s) indication.
What is an advantage of using metallic sodium filled exhaust valves in aircraft reciprocating engines?
A. Increased strength and resistance to cracking.
B. Reduced valve operating temperature.
C. Greater resistance to deterioration at high valve temperature.
Reduced valve operating temperature.
The primary concern in establishing the firing order for an opposed engine is to
provide for balance and eliminate vibration to the greatest extent possible.
Exhaust Stroke
The primary purpose in setting proper valve timing and overlap is to
obtain the best volumetric efficiency and lower cylinder operating temperatures
Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?
Reduced valve overlap period.
Intake and exhaust valves will open early and close late.
A power increase by shortening the exhaust event.
Reduced valve overlap period.
Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by
replacing the push rod.