Nose gear of this 491st B-25D Mitchell bomber has begun to retract as it takes off from Yang Chiseh Airfield, Yangkai, Yunnan province, China.
This is an early "D" model which still has the retractable ventral (bottom) turret installed in the fuselage just behind the wing. These turrets used a periscope sighting system with gunner facing forward while kneeling over and looking downward into the sight with the turret rotating and swinging the guns up and down. Because of the disorientation this cause the gunner, and difficulty in keeping these turrets operational, the 491st Squadron and other squadrons of the 341st Bomb Group, removed them to save weight which could be used for more fuel or bombs. Instead, the simple mounted two machine guns on a simple swivel mount in the hole where the turret had been.
Toward the end of the B-245D production run no ventral turret was installed in the planes, this was also true for B-25G, B-25H and B-25J models.