Analysis of information sources in references of the Wikipedia article "Boeing YB-40 Flying Fortress" in English language version.
"...factories were trying to fine a more effective solution to the B-17's lack of forward firepower...This solution was the Bendex Chin Turret. This turret had originally been used on the YB-40 gunship project. While this experiment proved unsuccessful, the chin turret was found to be a major improvement to the B-17's forward firepower. This turret was fitted to the last eighty-six B-17Fs to come off the Douglas assembly line starting with block B-17F-75-DL.
"...factories were trying to fine a more effective solution to the B-17's lack of forward firepower...This solution was the Bendex Chin Turret. This turret had originally been used on the YB-40 gunship project. While this experiment proved unsuccessful, the chin turret was found to be a major improvement to the B-17's forward firepower. This turret was fitted to the last eighty-six B-17Fs to come off the Douglas assembly line starting with block B-17F-75-DL.
