B-17 Flying Fortress - Production-block B-17F-15-DL: 42-3004 to 42-3038

Flexible gun mount in radio-room hatch, two .50-calibre staggered nose side guns, astrodome and astrocompass, provision for Lorenz blind approach equipment, vacuum-operated instrument air filters, pyrotechnic signals and pistol stowage and A-12 oxygen regulators all added.