George Lendich wrote:

Paul,
I was scratching my head wondering where you got that last design from and then realised it's the Ross - I happen to like the
Ross except for the large back plate and that's probably needed as the ribs don't carry around the corner - I'm unsure on that
particular aspect though !

Consider the bell housing as a large cylinder with a plate cap on one end
and a flange on the other.

You don't really need the ribs to carry around the corner. The front plate
is in bending from gyro loads and supporting the plate around its edges is sufficient.
The bending moment on the ribs goes to zero as you get near the edges of the front plate.
The small ends of the ribs feed fore and aft loads directly into the large
cylinder surrounding the starter ring gear. The small ribs near the mounting bolts
take the bending moment out of the large flange.

PL

However the Ross has a flange at the front to take the PSRU housing (I like that bit and will incorporate that into the Aussie
design).

In this design we are trying to adapt to Tracy's PSRU (which I think is the way to go in the USA) which has the long 1/4" bolts.
Now unless Tracy is willing to change his design - which I suggest he isn't, the current set-up is probably the best way to
adapt to it.

The Aussie design will have the thicker plate at the front and probably a 9" footprint for the PSRU housing (this will reduce
the housing face ribs length by 1/25". With the flanged PSRU housing bolting to the plate (short bolts) - matching the
Bellhousing flange.

I don't know whether to indent the centre or leave it void  (inside the flange support ring section). If I leave it void I will
have to consider some other oil seal strategy.
George (down under)

 
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