Paul


got the files  and have the material here...I have enough to
 make at
least 8 plates.I will  make 1 for inspection, then if you want
more......

the pressure caps  can be done as well.. get the geom and advise
 on
material....

jeff

OK do we have any other buyers? Speak up  now.

Paul Lamar


Paul
can you publish the list of those that spoke up so we can
 verify you
have us down... Count me in.

Mike C.

I don't have a list.
People should contact Jeff directly.

jeff doddridge <4starr@cox.net

Paul Lamar


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
Ok, reversed the direction of the torque [one mouse click and
changed one
other setting.. I had it set up w/ 1800lb's /hole rather than
1800lb's total.. one
more mouse click to change than] After re-running it.. here's the
results... they
look good to me..:) but then I'm not actually an engineer :)

Jarrett
Thanks Jarrett. That fixed it.  They do look good. As you pointed out
the spools will add stabilization. The deflections as is are down
in the
range of less than a thou. The cups are lightly stressed so they
could be
trimmed off by 45 degrees. I did not have Jeff do that as it would
add to the cost.
I may have to make some minor iterations having to do the the
position of
the RX8 bolt so I'll tweek the higher stress areas to make it
better while I am at
it.

Paul Lamar

Also just for reference, the corner fillets [weld beads] for the cups was
set at R0.2" so if a person put a slightly larger radius [assuming it is
as strong as the base material] you'd clear up that small area of
higher stress [or at least reduce it significantly]. I picked that number
just so it was less hassle for filletting. [If I'd gone larger it would have
taken a bit more time to get the fillets to 'flow' like a weld bead.. I was
trying to get it done as fast as possible.. due to time constraints elsewhere...]

Btw, this is my 'redrawn' model which is w/in a few % of being an
exact copy of yours. I found [I think] that my FEA issues on your model..
didn't have anything to do w/ your model..[my IT issues over the weekend]
but that was after I got these done.. I'll maybe go back and preform the
same process on your actual model and see what I get.. I'm sure the
difference will be impossible to see..

I'll let you know later tonight..

Jarrett

Well Jeff made a few minor changes here and there so what we have is close enough.
Did you put a weld fillet at top and bottom of the cups?


Paul Lamar