The Two ways for Reverse Operation:

First one (preferrable) for new aircrafts:
Once the engine power lever is moved backwards and lifted over an idle stop gate (protection against unintended reverse) into the beta range, a micro switch will activate the solenoid valve, which opens the high pressure servo line to the propeller. A cam will advance the power control for increasing power to increase negative thrust.

Second one (acceptable) for existing aircraft:
Instead of installing a complicated power lever and a cam, it is acceptable to use a guarded switch for activating the solenoid valve, which opens the high pressure line. As soon as the blades enter beta range, the engine throttle can be used for increasing reverse thrust.

Once the system is activated, a yellow warning light goes on and informs the pilot, that the propeller blades have entered beta range. As an additional protection against unintended reverse in flight, either the micro switch of a retractable landing gear (if applicable) or an air pressure switch installed at the aircraft speed indicator must close the power line to the solenoid valve.
Return from reverse is performed by de-activating the solenoid valve for leaving the high pressure mode. At this moment, the high pressure servo line will be closed and normal operation with the regular governed servo pressure is continued. Both the installed return spring inside the hub and the counterweights move the blades automatically back into a positive thrust angle.

Natural composite blades with fiber reinforced epoxy cover and metal leading edge protection are used to minimize weight at the highest amount of safety against fatigue fractures due to vibrations.

Available certified Propeller Models (pdf):

MTV-5-( )-R (M),MTV-6-( )-R (M),MTV-9-( )-R (M),MTV-12-( )-R (M),
MTV-14-( )-R (M), MTV-16-( )-R (M), MTV-21-( )-R(M), MTV-22-( )-R (M),
MTV-25-( )-R (M), MTV-27-( )-R (M)

Propeller Designation System (pdf)

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