Paul,

Is there a previous post talking about the concept/physics etc of the 3 pt. shwertz beam style mount?

Off hand I'd think the rear rubber rod end is a bit suspect. But then I've never looked at the facts.

Thanks
Ken

The 3 point Schertz beam concept as far as I can determine was invented by
Jim Griswold the designer of the Piper Malibu and the Questair
Venture. It is a very clever way of taking almost all of the load from
the engine mount using only two low cost $10 industrial rubber bushings
and a small rod end or two. The trick was to put the beam near the CG of the
engine/PSRU/prop combination.  It was not called that at first.
Bill Schertz on here adapted it to the rotary in a clever way.

Here are some pictures of the Questair implementation.

People that have owned Questairs say the vibration level is
very low for an IO-550. The trick to optimize top speed is
use a left and right hand thread ball joints at the rear and adjust
the down thrust angle for best top speed.

The rear 1/2 inch rubber rod end is over kill in this application because
the Schertz beam is near the engine CG.  Therefor there is less than
50 pounds of force on the rear rubber rod end. Way less in most cases.
The rubber rod end is rated at 270 pounds. If you think that is small
take a look at the size of the rods ends used in the Questair.

Paul Lamar

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