RPL

Question 0

What is the function of a pushrod and rocker arm in a piston engine?

Answer 0

The pushrod is engaged by the camshaft to pivot the rocker arm, opening a valve in the cylinder.

Question 1

State the function of cooling fins in a piston engine.

Answer 1

Act to remove heat from the system.

Question 2

Describe the four stroke cycle of a piston engine.

Answer 2

Induction
Intake valve opens. Piston moves down the barrel. Fresh fuel/air mixture is drawn in.

Compression
Both valves closed. Piston moves up the barrel. Fuel/air mixture is compressed to an eighth its original volume.

Power/Ignition
Spark plugs ignite the fuel/air mixture. Piston is forced down the barrel.

Exhaust
Piston is forced up the barrel, expelling gases through exhaust valve.

Question 3

List two factors affecting power output of an engine.

Answer 3

1. Quantity of gas induced into the cylinders.
2. Temperature reached during combustion.

Question 4

Describe how the movement of a piston emparts rotational energy to the crank shaft.

Answer 4

The linear force of the piston moving through the cylinder translates through a connecting rod to the crank shaft.

Question 5

List four symptoms of detonation and the actions to mitigate the problem.

Answer 5

Symptoms:

1. Rising cylinder oil temperature
2. Significant power loss
3. Vibration
4. Pinging sound from engine

Mitigation:

1. Mixture rich
2. Reduce power
3. If climbing, increase IAS to improve airflow

Question 6

Describe engine overspeed.

Answer 6

Engine overspeed occurs when the RPM becomes too high. This puts excessive loads on engine components (valves are especially vulnerable). Tachometer red line indicates this maximum RPM.