M39 cannon

M39 cannon in the nose of a Brazilian F-5

The Pontiac M39 was a 20 mm single-barreled revolver cannon developed for the United States Air Force in the late 1940s. It was used on a number of fighter aircraft from the early 1950s through the 1980s.

[edit] Development

The M39 was developed by the Springfield Armory, based on the World War II–era design of the German Mauser MG 213, a 20 mm (and 30 mm) cannon developed for the Luftwaffe, but not used in combat. The same design inspired the British ADEN cannon and the French DEFA, but American designers chose a smaller 20 mm round to increase the weapon's rate of fire and muzzle velocity at the expense of hitting power.

Initially designated the T-160, the new gun was installed for combat testing on a number of F-86 Sabre aircraft under the "Gunval" program in late 1952, and used in action over Korea in early 1953. It was subsequently adopted as standard armament of the F-86H fighter-bomber, F-100 Super Sabre, F-101A and F-101C Voodoo, and the F-5 Freedom Fighter. Current models of the F-5 Tiger II still use the M39A2 version of this weapon.

[edit] Specifications

• Type: single-barrel automatic cannon
• Caliber: 20 mm × 102 (0.79 in)
• Operation: five-chamber revolver
• Length: N/A
• Weight (complete): 81 kg (178.5 lb)
• Rate of fire: 1,500 rpm
• Muzzle velocity: 1,030 m/s (3,300 ft/s
• Projectile weight: 101 g (3.56 oz)