In the middle of the third flight, there was a very loud "BANG" that sounded like a gun shot. I was making a sweeping turn over the field when the left wing panel snapped at the root and the results are shown in the following pix! I realized then that opening the wing to install the retracts meant removing the covering from a large area which weakened the structure too much. Thus it failed in the wheel well area - but it sure didn't go quietly!!
The following shows how the engine had to be dug out of what was thankfully a "soft" field. Although one wing was found at the other end of the field, I have grouped it in the forensic shot to show all the pieces.