B- 17 ‘FLYING FORTRESS’ 75TH ANNIVERSARY AT AIRVENTURE 2010 The Flying Fortress is turning 75 this year and EAA will be celebrating with several events during EAA AirVenture Oshkosh 2010,
including a special evening program on July 28—75 years to the day of the B- 17’s first test flight. For details visi t www.AirVenture.org.
fter the December 7, 1941, attack on Pearl Harbor, military per-
sonnel by the thousands trained as aerial gunners for the U.S.
Army Air Forces. A majority of them trained for gun positions on
either the Boeing B- 17 Flying Fortress or Consolidated B- 24
Liberator. Operating at bone-chilling altitudes well above 25,000
feet, the men inside these aircraft, especially the gunners, had a specific task—to
shoot down the enemy fighters before they themselves were shot down. From
various gun positions, these men operated inside the confines of their bomber as
a coordinated team in defense of their aircraft.
But there was one other gunner, encased in a sphere called the Sperry ball
turret, who was removed from the rest of the crew as he protected the vulner-
able underside of the aircraft. The B- 24 and B- 17 looked nothing alike but
shared one common trait: both
used this new and formidable
defensive weapon slung
beneath their bellies.
Many men felt that the ball gunner
position on a B- 17 or B- 24 bomber
was the worst possible place from
which to fight a war.
SPERRY BALL TURRET
Before World War II the major-
ity of gun stations located on
most twin- and four-engine
bombers used a single, fixed machine gun with iron front sights as its primary
defensive weapon. The gun locations protected the nose, top turret right and left
waist, and all the way back to the tail gunner position. By late 1941, the Sperry
Corporation had created a much-needed defensive ball turret for the bottom
portion of B-17s and B-24s called the A- 2.
Three feet in diameter, it contained twin
Browning .50-caliber machine guns, a
Sperry K- 4 automatic computing gunsight,
interior lighting, a first aid kit, an oxygen
regulator, and a small radio. Best of all, it
could spin 360 degrees in azimuth (horizon-
tal rotation of the turret). The turret guns
could also be lowered or raised from 0 to 90
degrees by the gunner, who sat in a fetal
position inside the ball.