Apparatus for adjusting pitch angle of propeller blades of a variable-pitch propeller. The blades being adjustable in a first blade pitch-angle range with positive pitch angles, in a second blade pitch-angle range, and in a third blade pitch-angle range with negative pitch angles. The second blade pitch-angle range is an intermediate range located between the first and the third blade pitch-angle range, which includes the pitch-angle range where blade drag is a minimum, and ranges of positive pitch angles with low thrust and of negative pitch angles with low reverse thrust. The apparatus provides adjustment of the propeller blades from the first to the third blade pitch-angle range and vice versa, and is designed to be operated so that at least a first group of propeller blades can be rotated through the second blade pitch-angle range, while propeller blades in another group are in a positive blade pitch-angle range.