I used to sweat bullets over the downwind turn issue... yes I have no life ....

But one day I started thinking about my free fight models and how they fly on the ragged edge of a stall to give the lowest sink rate. On a free flight model NOTHING matters but the sink rate.

Now some of these are light rubber models and some are heavier engine powered models but they all have this edge of stall minimum sink rate trim. So if the downwind turn thing matters you'd expect it on the windier days to stall or show signs of a near stall as it turns towards it's downwind leg. But this doesn't happen. They just merrily fly their circular path in fine form regardless of how tight or open the circles are. And I generally like a tighter pattern in order to stay in the thermals.

This same behaviour has also been noticed in my RC gliders where I commonly set in my thermal circles with the trims for longer flights and only nudge it here and there as it merrily circles and drifts downwind.

So to my mind I'm now happy that any down wind turn shenannigans are totally pilot induced and have nothing to do with the model