Originally Posted by
AW009
The line between genius and insanity is a very fine one. But out of my technical view, the „suspension bar solution“ of (SUPER) PUMA - as realized by AS/ECF/AHF - might be genius, but is'nt at all ingenious
This brings up an interesting point. There was some discussion of design issues with the H-60/S-76/S-92 main rotor drivetrain. One thing I would point out is a fundamental difference between the design of the main gearbox structural attachments of the H-60/S-76/S-92 versus the EC225 in terms of fault tolerance. The Sikorsky design transfers rotor loads to the airframe using the gearbox housing, while the EC design transfers most rotor loads to the airframe using a set of struts. Both Sikorsky's stressed housing and EC's strut arrangements are attached to the airframe at three locations, and failure of just one of the three attachments would likely be catastrophic. If you take a close look at the picture of an S-92 main gearbox below, you'll note that the airframe attachment uses two bolts at each location, which provides single fault tolerance capability for this flight critical fastener function. The single clevis pin used at each end of the EC225's struts has no fault tolerance capability.
It might be possible to make the EC225 strut arrangement fault tolerant if two independent struts could be used at each of the three attachments, where one strut is capable of continuing safe operation in the event the other strut fails (assuming of course the kinematics of the system can be made to work properly).
