# Model B-17F and G bombardment airplanes are four-engine-mid wing monoplanes. The approximate over-all dimensions are: length, 74 feet 9 inches; height, taxiing position, 19 feet 1 inch; span, 103 feet 9 inches. Electrically operated landing gear, tail gear, wing flaps, bomb bay doors, and hydraulically operated brakes and cowl flaps are provided. Defensive armament of the B-17F consists of three turrets, each mounting two .50 caliber machine guns, and five single flexibly mounted .50 mounted .50 caliber machine guns. The B-17G has an additional power turret just below the nose of the airplane and controlled from the bombardier's compartment. Provisions are made for loading 2000-pound or smaller bombs on racks within the bomb bay, and one bomb , up to 4000 pounds may be carried under each wing. Automatic flight control equipment is provided.