Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PPL - Airtech > Engine > Flashcards

Engine Flashcards

1
Q

Two main classes of aircraft engine

A

Piston and Gas

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

Four types of piston engine

A

Radial, Inline, Inverted inline, Horizontally opposed

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

Radial engine cylinder arrangement

A

Cylinder are arranged in a circle around the crankshaft

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

Inline engine cylinder arrangement

A

Cylinder arrangement in one or more lines, either upright or inverted

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

Standard piston engine today

A

Horizontally opposed as it is

  • Low bulk and streamlined to reduce drag,
  • Ease of cooling
  • High power/weight ratio
  • Positioning of the thrust line to give enough propeller ground clearance
  • Good visibility from the cockpit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Horizontally opposed cylinder arrangement

A

Cylinders arranged horizontally in two lines on opposite sides of the crankshaft

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

What do piston (reciprocating) engines use as fuel

A

Aviation gas (AVGAS)

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

What does the piston do

A

Moves back and forth within the cylinder and provides a gas-tight seal

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

What does the connecting rod do

A

Connects the piston to the crankshaft

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

What does the valves do

A

Open and close alternatively to admit the fuel air mixture to the cylinder and to enable the exhaust gases to be expelled

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

What does the cylinder do

A

Provides the enclosed space for combustion to take place

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

What does the spark plugs do

A

Ignite the compressed fuel air mixture in the cylinder

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

What does the crankshaft do

A

Converts the reciprocating movement of the piston to a turning motion and transmits the power developed in the cylinders to the propeller

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

How does a piston engine work

A

The piston moves up and down inside the cylinder, in petrol engines a mixture of vaporised fuel and air is burned, the heat generated causes the gases in the cylinder to expand rapidly and push the piston down the cylinder. The reciprocating movement is converted into a rotation of the crankshaft and the attached propeller.

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

Energy changes in the piston engine

A

Chemical energy in the fuel is first converted to heat energy by burning it in the cylinder and then to mechanical energy to turn the propeller and develop the thrust required for powered flight

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

What is one stroke

A

The full movement of the piston either up or down in the cylinder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many revolutions are in a four stroke cycle

A

Two

18
Q

What are the four strokes

A

Intake, compression, power, exhaust

19
Q

What happens during the intake stroke

A

The fuel air mixture is sucked into the cylinder past the open inlet valve at the top, as the piston descends toward the crankshaft, pressure in the cylinder is reduced and the fuel air mixture flows in as a result of the higher pressure in the intake manifold.

20
Q

What is the intake manifold

A

The system of pipes which leads the mixture from the carburettor to each cylinder

21
Q

What is the charge

A

The volume of mixture drawn in on each induction stroke

22
Q

What happens in the compression stroke

A

Early in the compression stroke the inlet valve is now closed and the piston moves back toward the cylinder head. With both valves now closed, the charge is fully contained within the cylinder; therefore it becomes compressed and as a result its temperature rises considerably. As the piston is completing the compression stroke, the fuel-air charge is ignited by the spark plugs and controlled combustion begins. This causes the gases in the cylinder to expand rapidly and exert a strong pressure on the piston which has now passed the top of its stroke.

23
Q

What happens in the power stroke

A

The piston is pushed with considerable force back down the cylinder, just prior to the completion of the power stroke the exhaust valve opens.

24
Q

What happens in the exhaust stroke

A

The piston moves back up the cylinder and the burnt gases are forced out of the cylinder to the atmosphere via the exhaust manifold, as the piston is approaching the cylinder again the intake valve opens in preparation for the next induction stroke

25
Q

How does a single cylinder engine get enough momentum to keep the crankshaft turning during the 3 strokes that don’t provide power to turn the crankshaft

A

A heavy flywheel is attached to the crankshaft

26
Q

What is essential for smooth operation of the four stroke engine

A

Multiple cylinders as the the engine will receive multiple power impulses during the 2 revolutions of the crankshaft

27
Q

In level flight or climbing in an aircraft with a fixed pitch propeller, what indicates power output

A

rpm gauge (tachometer)

28
Q

The higher the rpm the ____ the power

A

Greater

29
Q

Why does the rpm gauge no longer give a good indication of engine power output during descent

A

The oncoming airstream increasingly helps to drive the propeller

30
Q

How is power output measured in engines fitted with a variable-pitch propeller and constant-speed unit

A

A combination of manifold pressure and engine rpm

31
Q

How is power varied in engines fitted with a variable-pitch propeller and constant-speed unit

A

By adjusting both the manifold pressure (with the throttle) and rpm (with the pitch control)

32
Q

What does the intake valve do

A

Admits the fuel air mixture to the cylinder

33
Q

What does the exhaust valve do

A

Allows the burnt gases to be expelled

34
Q

Camshaft function

A

Ensures that valves open and close at right times

35
Q

What speed does the camshaft operate at

A

Crankshaft speed

36
Q

What does valve lead, lag and overlap do

A

Help engine breath better

37
Q

Valve lead

A

Early opening of the exhaust valve

38
Q

Valve lag

A

Late closing of the intake valve

39
Q

Valve overlap

A

Both valves open at the same time

40
Q

Ignition

A

High voltage spark occurs across the points of spark plugs fitted to each cylinder, which enables a controlled flame to start moving through the compressed fuel-air charge so that max cylinder pressure develops at the most advantageous stage of the power stroke

PPL - Airtech (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions