Originally Posted by
das Uber Soldat
I say energy as a stand in for 'energy'. GPE + KE = Energy. Looking at the graph, total energy remains relatively constant.
Does it not?
No, it drops off precipitously at the end, along with altitude as the speed shoots up. But more to the point, it's speed and not TE that matters for ~1G stall. You can haul any low-performance plane 45 degrees up and coast it into a stall, and the TE will stay about the same. I.e., you won't be able to tell what's about to happen from a TE graph.