Picking the “right” airfoil for model aircraft

According to this tutorial, a modified flat-bottom airfoil is what I need for my future aircraft. I've bee searching for ages, and couldn't find a picture of it. Could anyone show me what it looks like?
 
is there anyone know about vtol airfoil ?
that is not different but sometimes ppl use some specials,
and pick it from a few models ...
 
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