Patent ID: 8109728

Claim:
An adjusting apparatus ( 9 ) for adjusting the pitch angle of propeller blades ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ) of a variable-pitch propeller in a first blade pitch-angle range with positive pitch angles at which the propeller blades ( 10 ) produce thrust, in a second blade pitch-angle range, in a third blade pitch-angle range with negative pitch angles, at which the propeller blades produce reverse thrust with the propeller rotating in the same direction, with the second blade pitch-angle range being a pitch-angle intermediate range located between the first and the second blade pitch-angle range, which includes the pitch-angle range in which the blade drag is a minimum, as well as a range of positive pitch angles with low thrust and a range of negative pitch angles with low reverse thrust, and with the adjusting apparatus being able to provide adjustment of the propeller blades ( 1 , 2 , . . . ) from the first to the third blade pitch-angle range and vice versa, characterized in that the adjusting apparatus ( 9 ) is designed such that, on the basis of it being operated by means of an operating apparatus, at least a first group (A) of the propeller blades ( 1 , 2 , . . . ) can be rotated through the second blade pitch-angle range, while the propeller blades in another group (B) are in a positive blade pitch-angle range.