We noticed a knocking sound from our wind turbine and thought it might be a disk rubbing on the stator but the problem turned out to be the nuts that were holding on the blade assembly. Two had disappeared and of the two that were left only one was tight. There is no chance to see if the missing nuts fell anywhere near the mast as the ground is well covered with snow at the moment.
The tail is a bit of an experiment and the turbine has been flying with it since November. It’s heavy gauge plastic coated corrugated sheeting, dimensions are 98x72cm and it is around the same weight as the recommended plywood tail. It seems to be furling on time but could be a bit bigger for holding the turbine better into the wind.