Well, the tail did have to get bigger to add a rear gunner:
the very early models were tail-gun-less.
I couldn't say off hand if there were other issues.

"Mortimer Schnerd, RN" wrote in message
. ..
Does anybody know the reason why they changed the empennage on the early
B-17s?
I was watching the History Channel earlier today and wondered why they
added the
heavy strake to the tail. I admit the early B-17s looked like the tail
would
come off if stressed too much. Did this actually happen or was it a
controllability issue for engine-out situations?