@riff_raff: The Image (
https://www.yumpu.com/xx/document/vi...0976/planetary) shows the TP400 main propeller gearbox on display at Paris Air Show 2013 (
https://upload.wikimedia.org/wikiped...er_Gearbox.jpg).
You are very right, the flexure flange as a unit with the ring gear is clamped between the front cover and the housing by means of through-bolts and is supported or propped up directly as a fitting element (Surface pressure) in the housing.
In my view this design transfers all radial forces by the ring gear (e.g. deformation or crack of ring gear due to mashing or squelching of satellite epicyclic (broken pinion gears) directly to the housing of the PGB.
Therefore I don’t see much mechanical difference to the CH-47 and also not to the H225/AS 332 Design, where the ring gear is one part with the housing structure. Of course the construction of the TP400-D6 PGB by AVIO AERO is much friendlier to overhaul and repair.
- In case of gear mashing the gear housing never will explode and the cardan shaft wouldn't do the very same as the main rotor of H225LP LN-OJF did in Bergen Crash.
- In (Super) PUMA MRGB the ring gear is part of the housing!
- To incorporate the outer bearing race of the planet gear as part of the gear might be a cheap solution in automotive transmissions, but we are talking about gearboxes in aviations. High quality outer bearing races by press-in conection to the planet gears don’t make much difference in costs, but are an enormous profit in safety and reliability.
Those are precisely the four crucial core issues which were not catched by the very loud ‘engineer’ Lonewolf_50, because he lapsed up to now into a suspicious silence!
In summary: The MRGB of (Super) Puma does not even meet the present standards of automotive engineering.