Palmer BB Machine Gun
Encyclopedia
The Palmer BB Machine Gun is a training weapon capable of firing ball bearing
s.
During World War II
, the USAAF and US Navy used thousands of Palmer BB machine guns to hone the skills of aerial gunnery. This much larger gun is cycled by an electric solenoid
and powered by compressed air
. The air pressure is higher, at 180-200 psi, but the velocity
runs between 500 and 600 f.p.s.
Ball bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit...
s.
During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, the USAAF and US Navy used thousands of Palmer BB machine guns to hone the skills of aerial gunnery. This much larger gun is cycled by an electric solenoid
Solenoid
A solenoid is a coil wound into a tightly packed helix. In physics, the term solenoid refers to a long, thin loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electric current is passed through it. Solenoids are important because they can create...
and powered by compressed air
Compressed air
Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....
. The air pressure is higher, at 180-200 psi, but the velocity
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
runs between 500 and 600 f.p.s.