Some time ago I attached a letter Jim Marske sent me from the co designer of the Opel in HBA, where he stated that the cause of the accident was the rear skid attached to the rear spar striking the ground and weakening it.I recall there had been speculation about a change in the spar structure (cutting a hole for the oxygen bottle??) which severely degraded the capability of the spar to withstand G loads. The report referenced above indicated the wing was designed for 8G, but that may have been before a hole was cut in the spar. Is any of this speculation correct, or relevant to the loss of the aircraft?
My plank is still progressing through it's flight testing. See video on YouTube.