Seriously, explain to me this scenario:
.40 size trainer flying into the wind and you pull up, with all that available airflow it loops easily. ok.
Now fly with the wind in say 20mph, pull up for a loop, notice how the plane has trouble, slows down and has troubles at the top of the loop, on occasion not even making it to inverted but hanging on the prop and then nosing forward either with the wind or towards gravity.  The issues at play again are drag and the airplanes non symmetrical design comparing front to back and how the machine behaves when the wind hits it from either the front or back.  The described situation plays out in slope soarers often too as I recall.