Bill or anyone,
I guess I need to
change my question to more specifics. For example, what do you think
of the single point attachment on the rear of the s-beam verses the more
substantial attachment of the flat plate mount. I personally don't know if I
feel comfortable with a single point of attachment in the rear. For
example, there may be times when the engine gets torqued around due to sudden
changes of flight direction.
Robert
Robert,
Flight loads are really not that large. Even if you
design for 10 gs you are only looking at 3000 lbs or so on the mount.
A more realistic number is 5 Gs. so
1500 lbs. At that loading, each side of the mount must hold up around
750 lbs.
750 lbs is not much for a steel truss structure.
Most mounts are hopelessly over designed. It would probably scare you to see a
mount that was designed for a factor of safety of 1 for actual flight loads.
Stiffness is a different matter. Whirl mode
oscillations can cause huge loads and are usually initiated by a perturbation
flight load. So your instincts are correct to be concerned about this issue.
Most mounts (even poorly designed ones) will work
under normal circumstances. Where you get into trouble is departure from
controlled flight and turbulence.
So what if your engine mount weighs 5 lbs
more?
When in doubt make it stout....(within reason)
;-)
Monty