B-17 Flying Fortress
The Boeing B-17 Flying Fortress or shortened to "Fort" by many was one of the two primary heavy bombers built in large production that destroyed factories, airfields and other strategic targets.
There were two models that were made in large quantity. The "F" Model and the "G" Model. One of the main visual differences between these models was all G's had the chin turret on the front of the aircraft. The early amd most "F's" did not have this feature but it was seen on some of the last production models.
The G model B-17 was heavier, had more armor plating in addition to the front armament and thus spec-wise was typically slower than the earlier "F" models. A few earlier variants were found in Hawaii and the Philippines, but many of these were destroyed by the enemy at the onset of the war in the Pacific or were rendered obsolete very soon as the "F" models were finished and deployed'