The USAF tank was a true "gas bag"--good for only four G empty and
just over two when full with very poor assymetric or "rolling" G
allowance. It was seldom used in other than ferry configurations for
peacetime/training missions. In combat ops it was always jettisoned
when empty.

In the Phantom's twilight service, F-4E and F-4G were flown with F-15 tanks
on the centerline. No maneuvering restrictions, although I am not sure if
they did anything to the rear Sparrow firing problem...

_____________
José Herculano