Production. B-17F heavy bombers. A woman plane construction technician fits the bombsight mount of a B-17F heavy bomber nearing completion at the Long Beach, California, plant of the Douglas Aircraft Company. The mount will carry the world's deadliest bombsight. Better known as the "Flying Fortress," the B-17F is a later model B-17, which distinguished itself in action in the South Pacific, over Germany and elsewhere. It is a long range, high altitude, heavy bomber with a crew of seven to nine men with armament sufficient to defend itself on daylight missions