To: Hone 22
I may be totally wrong but to the best of my recollection the H-269 / 369 models have static masts. The rotorhead is mounted on the static mast and is isolated by thrust bearings and held in place with a Jesus nut that was designed by Sikorsky and used under license by Hughes. A drive shaft is installed and it is splined to the output gear and is attached to the rotorhead by a series of bolts. I believe that these bolts are of sufficient strength that the seizure of the transmission will not cause the bolts to shear. The energy required to shear these bolts would have to come from the moment of inertia of the rotating rotorhead. The energy required to fracture these bolts would be so great as to totally fail the rotorhead. At least I believe this to be true IMHO.
The EH-101 was designed to have a shear point that would fracture if the transmission seized. The transmission is designed so that if this fracture were to occur the tail rotor would continue to rotate and one hydraulic pump would continue to function. As indicated above the energy to cause the fracture is the kinetic energy of the rotorhead. This kinetic energy is transmitted from the blade to the damper and then to the rotorhead. There is one small problem. The damper was designed to have a maximum tensile and compressive load of 1800 pounds with a safety factor of 1 1/2 or 2700 pounds. The load that is required to initiate the fracture is considerably higher than 2700 pounds so that if a fracture would occur the dampers would be destroyed. The destruction of the dampers would result in loads being inputted into the elastomeric bearings most likely causing them to fail as well.