On a completely unrelated note. I was wondering why a two point rear
 stabalizer mount is used with the combined engine mount psru aapter. It
was
 mentioned that there was a bending moment on the ends of the plate and
that
 during a flight test drop onto a runway some bending had occured.Obviously
 we don't design for this operating condition, but for normal use. It just
 seems that if the stabalizer mount that was a three point triangle it
would
 help counteract gyroscopic loads from the propeller at increased angles of
 attack like for climb. Are we just inheriting the two point link from a
 previous successful installation without necessairly evaluating it, or is
 there some not obvious reason other than weight concerns.
 george grimes

 I don't recommend a two point rear stabilizer mount.
 How did you get that impression?
 I recommend a single rear engine mount.
 Which photo did you see that in?
 Can you email it back to me?

 Paul Lamar


Test drop onto runway did NOT bend the MM plate.  It's much tougher
than that.  I don't know if the main wheel caught first and caused the
prop to hit the ground or if the prop tip caught a clump of dirt, but
it was the sudden stop and 120 deg rotation that bent the MM plate.
See my earlier message for complete description of the accident.

Bob W.

--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://roblinstores.com/


I think George is missing some 3D's on the rear motor mount schemes.
Here are some. There are a variety of ways of doing it.
The loads are very low. Sometimes on the order of 50 pounds due
to the motor plate being near the CG of the engine, PSRU and prop
combination.


Paul Lamar

Paul, I was refering  to a  post in answer to C Smith of sept 16 showing a
dxf drawing of the oil pan tabs titled "oil pan back view" apparently spaced
to sandwich a rod end detailed in a lower picture, and on the sept 8 post  "
final zenair plate mount"  there is a picture IMG 0158.jpg and drawing
zenith 9a jpg and illustrations above on this post show several variations
of a single link design. Also shown on this post is a design with a cross
tube and bushings with the through bolt passing thru both the tabs on the
tube and the tabs on the engine which seems to be a much better deal.It just
seems that with the perfect front motor mount/psru plate about to
standardize mazda conversions there ought to be a standardized rear mount to
encourage someone to build the tubular support structure for common
airframes. Combined wih the Tracy Crook PSRU and EFI setup and your intake
system the future looks really good.

george grimes

The rear mount is more of a problem accommodating a wide range
of firewall hard point designs. Sometimes the best thing is a horizontal
strut back to a fifth hard point on the firewall. Several airplanes
are built like that. Tube and rag fuselages are sometimes the hardest
to accommodate.


Paul Lamar