Paul, I was reflecting on the beam plate design, in it's present
configuration. I notice that the Barry cups are in essence butt
welded to the ends of the beam. Given that the welding process
destroys the heat-treat properties of the aluminum in the heat
afected zone, is this method of attachment strong enough to hold
the engine and absorb all of the forces incurred? I'm not an
engineer, but I do understand the welding process, so please
don't take offense. I'm just posing a question.
C. Smith

Absolutely.

If you take a 6.5 G hard landing drop in and assume the engine
weighs 300
pounds the shear force on the welds is 2000 pounds.
Lets assume for the moment all force is applied to only
one cup. The one closest to the engine.

If the total weld area taking both sides of the cup is .25 inch by
3 inch long
that is an area of .75 inch. .125" per side.  Therefor the stress
is 2000 / .75
or 2,666 psi. The  tig weld tensile strength is given in this
referencea about 25,000 psi so we have a factor of safety of 10.

http://www.aps.anl.gov/Science/Publications/lsnotes/ls254/ls254.html
Paul Lamar
Which is a HUGE under estimate. We are allowed to use 75Ksi in all
 our welds here at my day job. [in 44w plate] W/ 7018 [or equal]
 welding materials.
 [We're talking MIG or Stick however.. I'm not sure about tig]
Fwiw
Jarrett
Would/could you please do an FEA with 700 ft pounds of torque
combined  with 1800 pounds of down force :)
Like Bob White crash. Full power full stall drop in crash landing.
Paul Lamar
K, 700 torque thru the bolt circle /mount holes. 1800lb's vertical
force, do we have any
coupled force from the weight of the engine and mounts deflecting?

Exact material? Are we talking a 3/8" weld fillet either side?

Btw, I've now realized that your talking Aluminum, my weld strength
numbers [sited] are for 44w [steel].. just for the record :)

Jarrett

3/8th sounds about right.
I assume 6061 T6 at least I hope so.

Paul Lamar

Paul, I gave this a whirl this AM but it's causing some glitches and I'm not sure
why.. May have something to do w/ the imported data? Anyway, I've just about
got it re-drawn and will post the results after than.. should be yet today.

Jarrett

Thanks Jarrett

Paul Lamar