Originally Posted by Flying Bull
It tends to tangle the blades from front and back, when die dirve shaft goes.....
Much less chance than surviving a tailrotordriveshaftfailure in a normal helicopter....
Thanks Flying Bull. This already tells me the shaft would have to be designed to handle full rear cyclic, and full collective, more-or-less as a fatigue loadcase. By this i mean that the shaft stresses at this torque would be low enough for the the shaft to never fail during its design life, since clearly failure would be catastrophic.
I would imagine that shaft will be carbon composite, and very substantial. The other problem is that the surrounding structure has to be stiff enough to avoid torsional and flexural resonance problems. At high rpm any initial flexure in the shaft would soon lead to catastophic failure.
Hmmm, them Chinook boys must trust the ground crews.
Dave, have you ever heard a chook fly overhead? Vibration from ground level is pretty high. Every rotation each blade intersects the vortices from the opposite rotor set, so you get persistent blade slap. Great noise though.
Mart