Cover photo: Ground crew loading 12,7 mm ammo in ball turret of B-17 bomber – England 1942

Text by John Andersen

Throughout the duration of World War II, the least preferred position for the crews of large American bombers unquestionably was the ball turret located in the belly of the aircraft. With these turrets, crews were called upon to defend B-17 Flying Fortresses and B-24 Liberators, primarily from the deadly threat of Luftwaffe fighters, along with other weapons. Constructed by the Sperry Co, with a diameter of just 6.7cm over 1 meter to avoid causing flight problems due to wind friction, this turret was a sphere made of aluminum and transparent polymethyl methacrylate (PMMA, plexiglass), armed with twin .50 caliber (12.7mm) machine guns of the AN (Army/Navy) version of the well-known M2, capable of firing 750 to 850 rounds per minute.

The space for the gunner was minimal, located in the lower hemisphere, resulting in the selection of typically short-statured officers with specialized training. To man the turret, they had to enter through a small hatch and sit in a specially designed seat, reclined in a fetal-like position with their feet positioned behind the transparent polymer observation window and parallel to the barrels of the guns. Their bodies were in a parallel relationship with the lower turret casing, where they had to endure rigidity in a narrow and uncomfortable position for much of the mission, lasting hours, breathing through a special oxygen mask and enduring the cold of high altitudes without any other protection than the specialized clothing of the bomber crews.

Directly above the gunner, vertically from the main body of the aircraft downward, was the oxygen supply system with tubing, the electrical system, and small ammunition boxes where the belts from the 500-round cubic ammunition stock of .50 caliber cartridges, located outside and above the sphere, slid. The small boxes were used to feed the ammunition belts into the turret space, enter the gun breeches, and collect the used casings to be ejected through a chute.

Essentially, it was a spherical trap of vertigo made of aluminum and glass. The fact that it was a sealed construction gave a new dimension to claustrophobia, as the gunner wasn’t in an enclosed space, but felt as if exposed to a void 30 thousand feet above the ground. Yet, the Sperry turret was simultaneously a mechanical marvel in the service of the USAF. The gunner had an exceptionally innovative optical reflector sight for the time, positioned precisely in front of his line of sight, extending from his position to the void between his legs where the enclosed observation window was located.

The sight was designed not only to calculate the refraction of the turret’s transparent surfaces but also to slightly magnify targets by reflecting light fed by an electric lamp into the sight mirror where the gunner’s gaze had to focus. Moreover, the entire spherical turret was attached to the aircraft’s fuselage, where it could rotate smoothly and without obstacles, literally 360 degrees, enabling the defense of American bombers. And while the continuous and rapid rotations almost immediately caused disorientation, the gunner had illuminated instruments showing both the position of his guns in relation to the aircraft and in relation to flight.

As for its role, the designers of the turret at Sperry Co believed that it did not need any additional armor as it was located beneath the aircraft’s fuselage. Therefore, it was difficult to hit, unless enemy fighters took upward trajectories to achieve a precision strike under the American planes, killing the gunners. Something that theoretically was useless since the target was the heavy bombers themselves and not just a part of them.

However, the gunner was extremely vulnerable in two scenarios: a) In the event of a forced landing with the belly of the aircraft, if there was a problem with the landing gear system. The turret had to be evacuated promptly as there was a significant risk of the turret being crushed upon contact with the ground. b) If the airplane was shot down and falling, the gunner in the turret was the only member of the crew who couldn’t have a parachute on or near him. To get it, he had to open the special hatch connecting the turret to the fuselage and move to the main section of the plane. There, he had to find it and put it on.

Given that the airplane was falling, for this to happen, the control from the cockpit needed not to have been completely lost, and the gunner needed to be informed as early as possible. Otherwise, if the airplane had taken a vertical trajectory, it would have been extremely difficult not only to exit the turret but also to manage to leave after putting on the parachute.

It should be noted here that despite the difficulties, it is remarkable that the first Medal of Honor for the US Air Force was awarded to Staff Sergeant Maynard Harrison Smith (nicknamed “Snuffy”, the Unsinkable).

Following is the five-line poem by Randall Jarrell published in 1945, titled “The Death of the Ball Turret Gunner”:

From my mother’s sleep I fell into the State,
And I hunched in its belly till my wet fur froze.
Six miles from earth, loosed from its dream of life,
I woke to black flak and the nightmare fighters.
When I died they washed me out of the turret with a hose.