> Yes, that's what I meant by front and back.  But you're 
> saying there is such
> a thing as an airfoil shape that at some orientation it 
> pushes to the right,
> and when it's flipped 180deg it pushes to the left

The shape is asymmetrical, so when it is at the back it automatically
'points' in the opposite direction compared to at the front (still in
the same direction rotation-wise).

Wouter van Ooijen

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