Endcap Static Stress Simulation

[MAVProxyUser]

Need to add a stress test for KG99 based frames that lack the end cap, and simulate the result of the bolt slamming into the back of the PLA based lower frame. It is known to crack frames.

This same flaw was known to manifest in real Interdynamic frames. It is rumored to be the reason Intratec frames use a threaded end cap.

[MAVProxyUser]

The simulation extension has a 30 day trail, else it is $185 per months.
https://www.autodesk.com/products/fusion-360/simulation-extension

We should be able to determine how to beef up the ass end of the frame to make it handle the stresses sans end cap.