Ball turret

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Ball Turret
A crewman poses with the Sperry ball turret of a Royal Air Force B-24, Burma, c.1943-1945
Service history
Used byUnited States, United Kingdom, China
WarsWorld War II
Specifications
Caliber.50 BMG

A ball turret is a spherical-shaped,

gun turret, fitted to some American-built aircraft during World War II.[1]
The name arose from the turret's spherical housing.

It was a manned turret, as distinct from remote-controlled turrets also in use.

ventral versions that became the most common version; thus, the term "ball turret" generally indicates these versions.[4]

Sperry ball turret

Interior of the Sperry ball turret of a preserved B-17 (2008)

Sperry and

B-24 Liberator, as well as the United States Navy's Liberator, the PB4Y-1
. The ventral turret was used in tandem in the Convair B-32, successor to the B-24. Ball turrets appeared in the nose and tail as well as the nose of the final series B-24.

The Sperry ball turret was 3 and a half feet in diameter in order to reduce drag, and was typically operated by the smallest man of the crew. To enter the turret, the turret was moved until the guns were pointed straight down. The gunner placed his feet in the heel rests and occupied his cramped station. He would put on a safety strap and close and lock the turret door. There was no room inside for a parachute, which was left in the cabin above the turret. The Ball Turret Gunner was the only man of the crew to not have a parachute on or next to him.

The gunner was forced to assume a

Browning AN/M2 .50 caliber machine guns which extended through the entire turret, located to either side of the gunner. The charging handles were located too close to the gunner to be operated easily, so a cable was attached to the handle through pulleys to a handle near the front of the turret. Another factor was that not all stoppages could be corrected by charging (cocking) the guns. In many cases, when a stoppage occurred, it was necessary for the gunner to "reload" the gun, which required access to the firing chamber of the guns. Access was severely restricted by the guns' location in the small turret. Normally, the gunner accessed the firing chamber by releasing a latch and raising the cover to a position perpendicular to the gun but this was not possible in the ball turret. To remedy that, the front end of the cover was "slotted". The gunner released the latch and removed the cover which allowed space to clear the action. Small ammunition boxes rested on the top of the turret and additional ammunition belts fed the turret by means of a chute system. A reflector sight
was hung from the top of the turret, positioned roughly between the gunner's feet.

A B-24J's Sperry ventral ball turret in its retracted position for landing, as seen from inside the bomber

In the case of the B-24, the Liberator's tricycle landing gear design mandated that its A-13 model Sperry ball turret have a vertically retractable mount, so that the turret would not strike the ground as the plane pitches up for takeoff or during the landing flare. The conventional landing gear of the B-17 allowed for a non-retractable mount, but if the plane was required to do a belly landing (such as in the case of landing gear system failure), the ball turret would likely be destroyed due to the lack of clearance, meaning anyone occupying the turret would be in a precarious position if unable to escape.

ERCO ball turret

PBM-3
twin-engined patrol flying boat which had many points of similarity in design and action.

See also

References

  1. ^ Aircraft Fire Control. Great Neck, New York: Sperry Gyroscope Company. Retrieved 26 May 2020.
  2. ^ Holley, Irving B. Jr. (June 1947). Development of Aircraft Gun Turrets in the AAF, 1917-1944 (Report). Army Air Forces Historical Studies. AAF Historical Office, Headquarters, Army Air Forces. Archived from the original on May 21, 2020. Retrieved 26 May 2020.
  3. ^ "My Dad Was A Ball Turret Gunner In World War II". HuffPost. 2015-11-11. Retrieved 2022-06-16.
  4. ^ Aircrewman's Gunnery Manual. Aviation Training Division, Office of the Chief of Naval Operations. 1944. Retrieved 26 May 2020.
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