YB-4O if my memory serves me, it was intended to be an escort platform. It carried 2 fifty’s in each of the waist positions, two top turrets, as well as the ususal, armament i.e. tail, belly, radio operator, and cheek blisters in the nose. But I understand from reading is that they were slower than the bombed up 17’s, and the program was scrapped.

They even tried it on a few B-24’s with the same results.