Four conical mounts are designed and used for cantilevering an

aircraft

engine.
You are using only two in a bed mount situation to accept 90% of the

total

load
in the radial direction.

Paul Lamar

True, but I have 4 of them.  Since these pics were taken the rear mounts
have been modified so there are 3 supporting rods.

Dave Leonard

The two rear conical mounts in your set up have near zero load as the CG of the
engine prop psru combination is located about where the front conical mounts
are located. That heavy rear cross beam is doing nothing and is along
for the ride. You could also save more weight by mounting the front rubber
mounts on the psru adapter plate and bypass most of the loads on Tracy's plate
spacers and long 10 mm bell housing bolts. This would get the front rubber
bushings 3 inches further away from the 1400-1800 degree F turbo housing.
This would then eliminate the large heavy plate you have sandwiched between Tracy's
spacers and the front end housing of the engine. I also see no diagonals
laterally bracing the front rubber bushing holders.

Not that I expect you to do any of this as there is nothing really unsafe about your
design perhaps with the possible exception of the non-existent lateral bracing but it is a 
good example of why this is not a good approach. On the other hand you have known 
about my approach to motor mounts as you have been on here a long time I therefore 
have no sympathy for you :) As I recall you and I had a bit of communication on this
subject a year or two ago when I criticized a similar mount on someone else's 
airplane. Little did I know at the time it was personal :)

I'll do a 3D on an aircraft engine to show the loads on a cantilevered conical mount
set up.

Paul Lamar
 
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