in any case as long as there is a rigid fit between rotor
mast and 2nd stage planet carrier it will take up radial load.
the bearing in the bottom of the conical housing will take up some load.
that was the principle of the load distribution that we just talked about!
even if you say there is enough radial play in the planetary bearing/gear to completely unload the 2nd carrier of any radial load from the rotor mast
it will be taking up the load as long as it is driven
Originally Posted by
Concentric
Also the suspension bars locating the upper mast bearing are unlikely to have contributed in any way to the fatigue crack in the planet gear that propagated to failure. Three bars is determinate and an ideal way of locating something with predictable distribution of loads. On this aircraft they failed as a consequence of gearbox breakup, they were not a cause of it. Once the lower location is lost, no number of bars at the upper bearing will prevent the mast pivoting. The bars can take axial loads only (i.e. in their own axis), normally tensile.
That is not what I am saying.
Picture yourself, the AC with rotor mast and MRA, but without the MGB.
Is it a rigid construction that could carry the load of the AC? No.
That is what I am talking about. If the MGB is a rigid part of the MRA
and MGB fails shattering the housing, the Rotor will detach.
In order to do this, you need to make a gearbox with a stiff housing.
Possibly add 7-10 susp bars.
The stiff housing is increasing load on individual gears and reducing lifetime of them, but if it could allow a total break-up of MGB without sacrificing the rigidity of the rotor assembly, in my view that would be a life-saving solution because it would allow to autorotate without the MGB
In the same way as twin-engine, emergency lubrication etc are needed.
There is no saying against a multiple failing MGB cannot be a rigid part of the AC airworthy capability.
So I dont say that either susp bars, conical housing or gears broke first.
I am saying the should never break together.