The identical shape of the leading edge and trailing edge is so that reverse airflow on the retreating blade can provide lift.weird... I've never seen a symmetrical airfoil mirrored in a way that the leading and trailing edges were the same. Must be aerobatic.
Didn't think of that. I thought it was for going back down. Huh.Now, now... these blades will fly equally well turning in either direction. Brilliant. Stop 'em in flight, shift her into reverse and wind them them up in the other direction for an easy way to fly backwards.