FIELD: control system. SUBSTANCE: change of relationship of number of blades of working members is effected through connection in one or both working members of complete or incomplete rated number of physical blades of working members of number of "generalized" blades preset beforehand. "Generalized" blades are groups consisting of two and more physical blades of given working member at reduced angular pitch of these blades at their equidistant arrangement over circumference. Amount of reduced angular pitch of physical blades in each "generalized" blade and angular pitch of "generalized" blades proper in each working member is determined assuming that sum of static moments of centers of pressure of all physical blades of given working member relative to any axis of its symmetry is equal to zero. EFFECT: enhanced efficiency. 1 dwg
