Compact advanced passive tip clearance control

A section of a gas turbine engine, comprising:

• a rotor blade configured to rotate about an axis;
• a case positioned radially outward from the rotor blade and extending circumferentially about the axis;
• a segmented blade outer air seal (BOAS) including a plurality of BOAS segments each being positioned radially outward from the rotor blade, movably coupled to the case, and configured to move circumferentially relative to each other such that a circumferential gap between each of the plurality of BOAS segments changes in size in response to a temperature change in the section of the gas turbine engine;
• and
• a circumferential locking tab coupled to the case, slidably coupled to the segmented BOAS, and configured to resist circumferential movement of the segmented BOAS relative to the case.

A gas turbine engine, comprising:

• a compressor section configured to compress air;
• a combustor section configured to receive compressed air from the compressor section, to combust a mixture of the compressed air and fuel, and to output exhaust;
• and
• a turbine section configured to convert the exhaust into torque to power the compressor section,
• wherein at least one of the compressor section or the turbine section include:
• a rotor blade configured to rotate about an axis,
• a case positioned radially outward from the rotor blade and extending circumferentially about the axis,
• a control ring being annular, positioned radially inward from the case, movably coupled to the case, and configured to move radially relative to the case,
• a segmented blade outer air seal (BOAS) including a plurality of BOAS segments each being positioned radially outward from the rotor blade, movably coupled to the control ring, and configured to move circumferentially relative to each other such that a circumferential gap between each of the plurality of BOAS segments changes in size in response to a temperature change in the turbine section of the gas turbine engine, and
• a circumferential locking tab coupled to the case, slidably coupled to the segmented BOAS, and configured to resist circumferential movement of the segmented BOAS relative to the case.