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

Since you mentioned it, I suggest you are averse to the single attach point at the front of the engine.

Mazda got over holding onto the engine by its aluminum nose (front cover) in the 70s with the last 12As. 

 

I can assure you that when stressed the 4 studs will crack out the front cover. It has very few attachment bolts to the front iron, and is not very well thought out as a mount for both engine weight, part of the trans weight, and torsion control. It is fine for mild street use and that's about it.

 

For aviation use, it would not be stressed as much as it is in the car in the bending mode. The beam or whatever would take out the torsional load and I think all would be well if you start with a cover that had not been abused, or is already cracking.  

 

The blade loss that generates the most catastrophic outcome would be from a forged aluminum blade, because of its weight. Another vote for carbon fiber blades. I read one story about a blade loss in a Mooney that ended happily in a corn field.

 

The engine was contained only by cables, wiring and the cowling latches remaining closed. None of the engine mounting attach points remained intact. That is a bunch of luck burned up at one time.

 

A more likely outcome would be that the whole assembly firewall forward will exit the aircraft in a small part of one second. The departing material and remaining blades will comprehensively damage the remaining airframe. Damaged or not the loss of that 500 pounds will result in a pitch up that will fail the spar and render occupants unconscious. So planning on 1/2 of a second from one mount style or 1/4 of a second from another style is of little value. The odds against this happening to you are one in a billion. But Murphy says probably on the first test flight. So add a cable along one top mount tube and another along one bottom mount tube, and use the mounting system that makes you feel good. As long as the cables are installed, they will not be needed. 

 

Lynn E. Hanover