More ANSYS runs

Using the 75/25 load split between LE and TE, and with the addition of the forward sweep cable, I re-ran the 6g loading case on my Goat wing.  Not altogether different, as you might expect.  The bowing shape is still roughly the same.  The maximum stress is roughly the same.  At first glance, the results are pretty equivalent.

 Maximum stress is still in the leading edge tube between the jury strut attachment and the wing root pin joint.  There is still some bowing of the main struts upward as the jury struts are pulled on by the main spar.  
Do note that these deflections are listed as approximately 0.5 inch.  With such a low-fidelity FEA, I'm expecting somewhere between 3-12 inches of actual deflection during the load test, but the point is to say that the shape shown in the analysis is scaled to be visible.  ANSYS has a true-load deflection option and it shows essentially no discernible deflection.  Beware of length scaling.



To answer a few other questions:

• I am too far into the build to change the main strut attachment location to the wing spars.  So, what you see in the FEA is what I have to work with.  Potentially I can add additional sleeve length or inner sleeves to the jury strut location or also change where the jury strut attaches to the main strut.
• I am not using Schrenk's approximation or an elliptical load distribution.  Instead, this loading comes from the AVL model, which is likely better than Schrenk for arbitrary wing planforms.  See a previous post to learn more about the AVL work.
• I have so much margin left in the wing structure near the strut attachment that I'm not going to run the asymmetric aileron loading case.  The FEA in my mind was more concerned with showing how much margin to yield or ultimate load that I had, rather than doing the detail-work checking for aeroelastic effects.

Finally, I'm thinking it's worth moving onward with the construction.  Additional sleeving can be added at the jury strut attachment location without invasive surgery, so it doesn't hurt me to continue on.  There is a kitchen renovation in my near-term future (July), so the time is ticking away before another major delay!  Ack!

I should probably add that I'm narrowing in on a decision to load-test to 4G's.  According to the FEA, this should be well below where I'd anticipate any yielding and is more than I plan on pulling (no loops, heh).  A cohort at work has even suggested it will be difficult to pull that many G's in the airchair, considering the high drag count and low-performance airfoil.  Self-limiting is good in this case :-)