Yank and Doodle appeared in PRIZE COMICS #13-68 (Aug 1941-Feb/Mar 1948).
Twins Rick and Dick Walters weren't old enough to join the Army, so they decided to become superheroes. Apparently, they also had super-strength and invulnerability when they were near each other, but that doesn't seem to play much in this story.
I'm not sure which was which. Wikipedia says Rick was Yank and Dick was Doodle. International Hero says it was the other way around. Toonopedia and Public Domain Super Heroes don't even bother.