The B-17 does not have a flight engineer station or panel. There are only two seats in the cockpit. In the 80’s we referred to the third crew member as the Crew Chief...he took care of logistics on the ground and supervised the passengers.
Again...the B-17 is a fairly simple aircraft made to be operated by comparatively very low time pilots. The WWII crew consisted of Navigator, Bombadier, Pilot, Co-pilot, Dorsal turret gunner, Radio operator, and the four gunners aft of the bomb bay.