what's "H.E. Flak"

[stephen f. polyak]

I suggest that H.E. (or HE) may refer to the type of ammunition being used; i.e., in this case, H.E. would mean high explosive. HE shells (allowing blast and fragmentation damage mechanisms) were commonly employed against aircraft, particularly in large caliber anti-aircraft (AA) weapons; e.g., 88-mm flak.

In addition to HE rounds, small caliber AA ammunition (e.g., 20 & 30 mm light flak), included non-explosive A.P. (or AP) armor piercing rounds.

Variants of both types (HE and AP) also included incendiary (I) damage mechanisms. In that case, the ammunition designations would be HEI and API.