Wind turbine rotor blade, wind turbine and method for operating a wind turbine

A wind-turbine rotor blade, comprising:

• a first rotor-blade portion;
• and
• a second rotor-blade portion,
• the first and the second rotor-blade portions together forming a total length of the rotor blade, and the first and second rotor-blade portions configured so that in response to a rotation of the rotor blade, at least one of the first rotor-blade portion and the second rotor-blade portion move relative to each other as a result of a centrifugal force acting upon the rotor blade in such a way that the total length of the rotor blade is altered to an altered total length, wherein the movement is along a longitudinal axis of the rotor blade,
• wherein at least a portion of the second rotor-blade portion is disposed in the first rotor-blade portion, wherein the first rotor-blade portion has an opening, a portion of the second rotor-blade portion being configured to move in and out of the opening of the first rotor-blade portion, and
• wherein the first rotor-blade portion has a guide device for guiding and supporting the second rotor-blade portion inside the opening of the first rotor-blade portion, the guide device having at least two guide elements for guiding the second rotor-blade portion in the direction of the longitudinal axis of the rotor blade, and at least two spring elements coupling the at least two guide elements to the first rotor-blade portion.