Apparatus and method for partially bladed rotor test

A rotor module, comprising:

• a blade cluster of a plurality of blades secured to a rotor disk of the rotor module;
• and
• counter weights secured to the rotor disk, wherein a center of gravity of the plurality of blades is zeroed out with respect to an axis “O” of the rotor disk and the rotor module further comprises an “X” axis and a “Y” axis each orthogonally arranged with respect to the axis “O” of the rotor disk and wherein the blade cluster and the counter weights are configured to provide a configuration with respect to the axis “O” of the rotor disk and a moment of inertia Jx about the X axis is equal to a moment of inertia Jy about the Y axis when the rotor module is rotated about the axis “O” of the rotor disk, wherein each counter weight of the counter weights includes:
• a root portion;
• a main body portion that extends away from the root portion;
• a pair of side portions each extending laterally away from opposite sides of the main body portion such that at least a portion of each counter weight of the counter weights is configured to have a “T” shaped tip portion;
• sacrificial side portions that extend radially outwardly away from respective ends of each of the pair of side portions;
• and
• at least one plate secured to one of the opposite sides of the main body portion in order to adjust a weight of the counter weight.

A method for zeroing out a center of gravity of a plurality of blades with respect to an axis “O” of a rotor disk the plurality of blades are secured to, comprising:

• securing a blade cluster of the plurality of blades to the rotor disk;
• and
• securing counter weights to the rotor disk, wherein the center of gravity of the plurality of blades is zeroed out with respect to the axis “O” of the rotor disk and the rotor disk further comprises an “X” axis and a “Y” axis each orthogonally arranged with respect to the axis “O” of the rotor disk and wherein the blade cluster and the counter weights are configured to provide a configuration with respect to the axis “O” of the rotor disk and a moment of inertia Jx about the X axis is equal to a moment of inertia Jy about the Y axis when the rotor disk is rotated about the axis “O” of the rotor disk, wherein each counter weight of the counter weights includes:
• a root portion;
• a main body portion that extends away from the root portion;
• a pair of side portions each extending laterally away from opposite sides of the main body portion such that at least a portion of each counter weight of the counter weights is configured to have a “T” shaped tip portion;
• sacrificial side portions that extend radially outwardly away from respective ends of each of the pair of side portions;
• and
• at least one plate secured to one of the opposite sides of the main body portion in order to adjust a weight of the counter weight.