To prevent rotor mast damage if hub moment springs are
not installed, the UH-1 square wedge assembly must be
If disabled helicopter does not have hub moment springs installed, install the UH-1 square wedge assembly
(13) in accordance with Figure 1, View A location, and Figure 4, as follows:
Figure 4. UH-1 Square Wedge Assembly
When installing wedge assembly it may be necessary to
slightly rock blades using fixed length tie-downs attached to
blade sleeve assemblies to place wedge assembly in correct
(1) Place the two rubber blocks from the square wedge assembly against the main rotor mast near the
bottom of the main rotor hub assembly, with the recessed cutouts in the blocks facing away from the
main rotor mast.
(2) Carefully slide the two rubber blocks up into the gap between the main rotor hub and the main rotor
(3) Verify that the stops on the main rotor hub full contact the rubber blocks of the square wedge
assembly and that the stops are within the recessed cutouts in the rubber blocks.
(4) Loop the lanyard attached to the rubber blocks around the main rotor hub and secure the snap onto
the other rubber block. The lanyard is designed to prevent the square wedge assembly from sliding
down and exposing the main rotor assembly.
k. The disabled helicopter is now ready for hookup to the recovery helicopter.