Propeller

Question 1

What does CSU mean?

Answer 1

Constant speed unit

Question 2

How do the blades move to a coarser pitch?

Answer 2

Counterweight and spring

Question 3

Do we have a CSU in the DA42NG

Answer 3

Not really. The DA42NG has an electric governor.

Question 4

What is the max t/o rpm

Answer 4

2300 rpm

Question 5

How long is this allowed

Answer 5

5 minutes per flight

Question 6

What is the max continuous RPM

Answer 6

2100 rpm

Question 7

Is any overspeed allowed

Answer 7

2500 rpm for up to 20 sec

Question 8

What kind of governor is in the NG

Answer 8

Electric

Question 9

What decides on the pitch

Answer 9

ECU

Question 10

What changes the pitch blade angle

Answer 10

Gearbox oil

Question 11

To increase the pitch, do you add or remove oil from hub?

Answer 11

You lower oil pressure

Question 12

What happens to rpm

Answer 12

Decreases

Question 13

If oil pressure increases in the hub, what happens to pitch

Answer 13

Pitch decreases

Question 14

What happens to rpm

Answer 14

Rpm increases

Question 15

What system allows unfeathering

Answer 15

The pressure accumulator

Question 16

What’s the pressure in it

Answer 16

320 psi

Question 17

When it activates, it moves the pitch into low or high pitch

Answer 17

Low

Question 18

How does the feathering work

Answer 18

Electric governor valve opens. All oil from hub leaves.

Question 19

Is feathering possible at all times

Answer 19

No, only above 1300 rpm

Question 20

What is the prop made of

Answer 20

Wood + reinforced fiberglass plastic coating

Question 21

Can we move the prop by hand

Answer 21

We should not

Question 22

What happens if we do

Answer 22

Could damage the gearbox

Question 23

If loss of oil pressure or engine failure, will the prop auto feather

Answer 23

No

Question 24

What will happen

Answer 24

Prop moves to high pitch angle

Question 25

How to feather then

Answer 25

The engine master must be off

Question 26

When the prop is turning, what happens naturally to the blades

Answer 26

Move to lower pitch

Question 27

What’s this called

Answer 27

Aerodynamic twisting

Question 28

How to offset that

Answer 28

Counterweight + spring

Question 29

The counterweights move the pitch into low or high pitch

Answer 29

High (coarser)

Question 30

When the prop is rotating under 1300 rpm, what prevents the prop from feathering

Answer 30

Pitch stop locks

Question 31

When you shut down the engine on the ground, does the prop feather

Answer 31

No

Question 32

Why

Answer 32

Pitch stop lock

Question 33

So how come you can feather in flight

Answer 33

Centrifugal latching mechanism disengage the pitch stop locks when > 1300 rpm

Question 34

Recap: what conditions you need to feather the prop

Answer 34

2: Engine master off and rpm > 1300 rpm

Question 35

What’s the prop pitch angle in the feather position

Answer 35

81 degrees

Question 36

How does the prop unfeather

Answer 36

By using oil stored in the accumulator

Question 37

What signals the accumulator to release oil to the hub

Answer 37

Engine master on

Question 38

Can one use windmilling to restart the engine

Answer 38

No

Question 39

What kind of CAS message could we get if we do

Answer 39

L/R ECU A/B FAILURE

Question 40

What does CAS mean

Answer 40

Crew alerting message