Propellers Flashcards
What is the construction material of the mt-Propeller?
Wood-composite construction with a fiber-reinforced plastic coating
The mt-Propeller features a combination of wood and advanced plastic materials for enhanced durability and performance.
What protects the inner edge of the mt-Propeller blades?
A rubber strip
This rubber strip is designed to provide additional protection against wear and damage.
What protects the outer edges of the mt-Propeller blades?
A stainless steel clad edge
The stainless steel edge adds strength and resistance to environmental factors.
What type of regulation does the mt-Propeller use?
Hydraulically regulated, constant speed, full-feathering
This mechanism allows for efficient and responsive control of the propeller’s pitch.
How are the blades moved to a coarse pitch?
By counterweights and spring tension
This system utilizes mechanical forces to adjust the blade pitch for optimal performance.
How are the blades moved to a fine pitch?
By gearbox oil pressure controlled by the CSU
The Constant Speed Unit (CSU) plays a critical role in adjusting the blade pitch based on engine performance.
What should be checked during a preflight propeller inspection?
Each blade, front and back, leading and trailing edges
What type of surface damage is common on propeller blades?
Surface nicks, especially on the rear face
What is the acceptable condition for minor surface nicks on propeller blades?
Minor surface nicks are acceptable
What maintenance is required if nicks or de-lamination exposes underlying wood fibers?
Maintenance is required
What condition indicates that maintenance is required in relation to the propeller hub?
If grease or oil appears to be leaking from the propeller hub
What does the ECU command the CSU to do?
Set optimum propeller RPM for percentage power commanded by pilot
How does the CSU control the propeller’s blade pitch?
By controlling the amount of gearbox oil in the propeller hub
What effect does increased oil volume in the hub have on the propeller?
Results in a finer blade pitch (higher RPM)
What is the oil pressure boosted by the Combi Pump?
Approximately 290 PSI
What is the maximum continuous power RPM?
2300 RPM
What is the overspeed limit and duration?
2500 RPM for up to 20 seconds
What type of governor does the DA42NG use?
mt P-877-16 electric governor
What is the maximum takeoff power RPM for the DA42NG?
2300 RPM (5 minutes total per flight)
What is the maximum continuous power RPM for the DA42NG?
2100 RPM
What should be done before turning off the Engine Master?
Power lever should be at idle
What happens to the propeller when the engine stops with RPM above 1300 RPM?
The propeller will feather
What prevents the propeller from feathering below 1300 RPM?
Coarse stop pins
What do the ECUs do as power is reduced while airborne?
Reduce propeller RPM until reaching 25%
What action do the ECUs take below 25% power?
Increase propeller RPM to ensure feathering if the engine is shutdown
True or False: Increased propeller RPM is associated with power settings below 25%.
True
What may cause propeller blades to move to the highest RPM setting?
A malfunction
This can lead to a condition known as propeller over-speed.
What should be done if over-speed occurs in a propeller?
Reduce power on the affected engine and terminate the flight as soon as practicable
This helps control the RPM.
What action should be considered if unable to maintain 2300 RPM or less?
Consider shutting down the affected engine
This is crucial for safety if power reduction fails.
What power setting should be used after takeoff in a DA42NG?
Reduce power levers to 92%
This should be done after reaching a safe altitude.
What is the recommended engine power setting during climbs above 14,000 feet MSL?
Reduce power settings below 92%
This prevents RPM from entering the yellow range.
What is the purpose of unfeathering accumulators?
Enable restarting an engine while airborne
They store pressurized gearbox oil to assist in propeller movement.
What do unfeathering accumulators store?
Pressurized gearbox oil in a nitrogen-charged metal cylinder
This allows for the movement of the propeller out of the feathered position.
What happens when the Engine Master switch is turned ON?
Accumulator releases gearbox oil to move the propeller out of the feathered position
This is essential for engine restart procedures.
At what speeds is the starter used to start the engine?
Below 90 KIAS
This is important for safe engine start procedures.
True or False: Engaging the starter while the propeller is wind-milling is safe.
False
It may result in an L/R ECU A/B FAILURE CAS message.
What may happen if the starter is disengaged below 500 RPM?
It may cause damage to the gearbox
This highlights the importance of proper RPM management during engine operations.
What is the maximum time allowed to restart an engine after shutting down for training purposes while airborne?
Within two minutes
Restart may not succeed if the engine is not restarted within this timeframe.
What are the two types of air start procedures defined for the DA42NG?
- Windmilling propeller at 120 to 140 KIAS
- Engine starter at 85 to 100 KIAS
What does FAA Airworthiness Directive 2018-18-02 limit regarding windmilling restart?
Use for emergencies only
This is to prevent failure of engine timing chain, loss of engine thrust control, and reduced control of the airplane.
What may happen if the starter is engaged while the propeller is wind-milling?
An L/R ECU A/B FAILURE CAS message may occur
This is a warning to avoid engaging the starter under such conditions.
