The first purpose-built attack helicopter was the AH-1 Cobra, originally developed for the U.S. Army during the Vietnam War. Typical armament included 2.75" unguided rockets on pylons, with a chin turret containing either two 20mm M61 Vulcan autocannon, two 40mm automatic grenade launchers, or one of each. They also could carry the BGM-71 TOW antitank missile
The U.S. Marine Corps is currently adding the AH-1Z Viper to its arsenal. The AH-1Z is an improvement over the previous version AH-1W Super Cobra. This new version of the aircraft is complete with a new twin-engine and a 4-blade rotor. As in previous versions, the Super Cobra is outfitted with the AGM-114 Hellfire, and can also carry AIM-9 Sidewinder missiles for self-defense against aircraft and helicopters.