P Piston Engine Power, Efficiency and Control Flashcards

1
Q

What 2 factors dictate the power of an engine?

A
  • The mass of charge

- The numbers of times per second that the charge is put into the cylinders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the power equation?

A

Power = (force x distance)/time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does power = plane mean?

A

Power = Pressure x Length of stroke x Area x Number of cylinders x rpm/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the total volume of a cylinder?

A

Volume of cylinder at BDC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the clearance volume of a cylinder?

A

Volume of the cylinder at TDC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the swept volume?

A

Volume of the cylinder between TDC and BDC

Total volume - Clearance volume = Swept volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the compression ratio?

A

A relationship between total volume and clearance volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is mechanical efficiency?

A

Measures the effectiveness of an engine turning the input power to output power. Taking into account friction and vibration most engines are 90-95% mechanically efficient. When factoring in thermal efficiency this falls to around 80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is thermal efficiency?

A

Defines how effective the engine is at converting fuel energy into producing mechanical work. All combustion engines are heat engines and heat is always lost, meaning thermal efficiency is 25-35% for a standard engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the relationship between thermal efficiency and compression ratio?

A

As thermal efficiency increases, the compression ratio increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the RPM gauge do?

A

Measures crankshaft RPM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What dos the manifold pressure gauge do?

A

Measures manifold pressure in InHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the boost pressure gauge do?

A

Measures manifold pressure in PSI relative to sea level pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the oil pressure gauge do?

A

Measures the oil pressure just after the filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the oil temperature gauge do?

A

Measures the oil temperature in the oil return line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the CHT (cylinder head temperature) gauge do?

A

Measures the temperature of the hottest cylinder

17
Q

What does the EGT (exhaust gas temperature) gauge do?

A

Measures the temperature in the exhaust gas stream

18
Q

What does the fuel pressure gauge do?

A

Measures fuel pump output pressure

19
Q

What does the induction temperature gauge do?

A

Measures the temperature are the carburettor inlet

20
Q

How to engine controls differ?

A

By colour and shape

21
Q

What colour and shape is the throttle?

A

On a panel: round
On a quadrant: cylindrical
Colour: black

22
Q

What colour and shape is the propeller control?

A

On a panel: round with large grooves
On a quadrant: crown shape with large grooves
Colour: blue

23
Q

What colour and shape is the mixture control?

A

On a panel: round with small protrusions
On a quadrant: round with small protrusions
Colour: red

24
Q

Why do we check the fuel pre-start?

A

Check for water contamination

25
Q

Why do we pull through inverted or radial engines before start?

A

To prevent hydraulicing

26
Q

3 starting procedure precautions

A
  1. Shut down if the start warning light remains on for 30 seconds or more after start
  2. Positive engine oil pressure should be indicated within 30 seconds of engine start
  3. In very cold conditions increased oil viscosity may make starting more difficult
27
Q

Which 3 after-start checks do we consider?

A
  1. Individually check magnetos to ensure ignition circuits are functional
  2. Carburettor heat should be off whilst the engine is running on the ground
  3. Prolonged idling should be avoided to reduce risk of spark plug fouling
28
Q

What are the 3 procedures for changing power settings?

A
  1. Slow, smooth throttle movement to reduce engine stress
  2. Reduce to max continuous as soon as safely possible after take off
  3. Constant speed propellers (rev up, throttle back)
    (Rev leads throttle when increase, throttle leads revs when decrease power)
29
Q

2 shut down procedures

A
  1. Allow engine to cool at low rpm before shut down

2. Do a dead cut check to confirm both ignition circuits are properly earthed

30
Q

What does black smoke indicate?

A

Excessively rich mixture

31
Q

What does blue smoke indicate?

A

Burning oil - worn or broken piston rings

32
Q

What does a high CHT indicate?

A

Cowl flaps may be closed

33
Q

What could cause excessive CHT?

A

Excessively lean mixture

34
Q

What can cause rough running?

A
  • Carburettor icing
  • Moisture in the ignition circuit
  • Problems with fuel delivery
  • Uneven compression in the cylinder