I was inspired by this thread last night, as I was headed toward a large red bardar at ridiculous alt in my Ta-152 I happened across a P40E at about 20k alt with a droptank on autoclimb. I dove in and was barrel rolling to get into wingman position when wings started waggling, the droptank flew off, and he put it into a flat spin hauling on his controls. I cut throttle and rolled in on him, giving him a half second burst and pulling off before I lost too much alt, figuring surely I'd done enough to put him down. Apparently I didn't take off anything vital, as I leveled out I saw him trailing smoke and RTBing.
Much more entertaining than just taking A Free Kill.
Wiley.