We were at 50 deg bank balanced flight with ower on in a c150 or 152.
The aircraft was pitched to the buffet then roll applied to level the wings.
The wing tip stalled throwing us over the top and straight into a high rot fully developed spin which was nothing like the normal spin. Rudder made not the slightest bit of difference and neither did progresively moving the stick forward.
It was one of my three this is it moments in aircraft