B-17G in an Army Air Force attack on Berlin. The group depicted is the 398th Army Air Force group of the 8th US Army Air Force which was stationed in England. The G model B-17 was designed to reduce frontal attacks that were raising havoc with the 175. Counting the chin turret and the ball turret the twin guns of hte dorsal turret, the waist guns and twin tail guns there were ten .50 caliber browning machine guns. Indeed teh "Berlin Express" depicted here was a true fortress in the sky.