henra;
I can't quite follow your numbers. To get kinetic energy, you need to add horizontal and vertical components of speed vectorially. If the airplane attained a speed of 50 kt at any time, it would need accelerate to a much higher speed (of the order of 180 - 200 kt) to be able to impact in nearly level attitude, whether stalled or not.
Drag is vertical only if there is no horizontal speed. The terminal velocity for cw=1 is 189 kCAS at sealevel.
regards,
HN39