Propellers and Electrical Power

What are the blades made out of?

High compressed wood (root) and lightweight wood (remaining body)

What is the blade surface covered in?

Epoxy fibreglass for sealing, painted with acrylic lacquer

What type of propeller is it?

Constant speed, fully feathering (can be unfeathered)

How are the leading edges protected from erosion?

Outboard, bonded stainless steel sheath

Inboard, self adhesive rubber strip

When can't you feather or unfeather the prop?

Can't feather if its not turning

Can't unfeather without oil pressure

Why are there counterweights attached to each propeller?

Centrifugal twisting moment causes the blades to fine, counterweights oppose this and move blades to coarse

How does the propeller governor work?

Engine driven, controls oil pressure in propeller pitch change mechanism

What is the propeller pitch change mechanism?

In propeller hub, piston moves in reaction to oil pressure and adjusts pitch of blades

What does changing of the oil pressure do?

Increasing oil pressure, blades fine

Decreasing oil, coarsens blades

What does the hydraulic accumulator attached to each governor allow?

Ability to unfeather

What is feathering of the propeller?

- propeller control moved aft past feathering gate

- Oil leaves propeller hub

- Counterweights and spring move blades to feather

- Check valve on accumulator closes

- Oil trapped in accumulator

How do you unfeather the propeller?

- Propeller control moved forward

- Check valve on accumulator opens

- Oil moves from accumulator to governor

What type is the main battery?

24V 10Amp hr lead acid battery

How does the main battery work?

In rear-right side of front baggage compartment, controlled with electric master switch, it's connected to the hot battery bus and battery bus

Wan you use the hot battery bus without the masters on?

Yes

How many alternators are there?

2 (1 per engine)

What is the type of alternator used?

28V DC, max 70 Amp, belt driven, located at the rear left side of the engine

What are the voltage regulators?

Controls alternator output and manages load sharing, provides overvoltage and ground fault protection (L/R ALTN FAIL)

What does the emergency battery power?

Artificial horizon and flood light

How long does the emergency battery supply power for, ideally?

1.5 hours