UH-1 Main Rotor Re-torque

This has been brought up before about a re-torque after main rotor installation. In this case the TM 55-1520-210-23-1 is not a help.

After the US military was fielded with the power dyne, the requirement for re-torqueing the main rotor was removed from the manual.

If upon installation the main rotor assembly was properly torqued with a calibrated power dyne or other hydraulic torqueing device a re-torque is not required. This is because torque is held until it stabilizes in the torque range.

If the torque was applied with a momentary type torque wrench it needs to be re-torqued after first flight. This is because the head will re-seat itself.

There is no longer a requirement for re-torque and why it has been removed from the manual. There is no longer a requirement to have the split cones have equal spacing as they will find their own place. I am including two diagrams out of the TM.

Any questions? Email us at UH1OPS@gmail.com Pete