History Of the Helicopter Gunship

Until the Vietnam conflict, military helicopters were mostly used for evacuating wounded troops. They were used extensively for this purpose doing the Korean War. Other roles included limited troop transport and observation.
The US involvement in Vietnam saw an increase in the use of helicopters as troop transports, often flying missions in which they came under heavy fire. The need for heavily armed helicopters soon became apparent. The Huey UH-1C troop transport was kitted out with machine guns and 2.75in FFAR rockets which were mounted on stub-wings attached to the chopper's fuselage. Other gunship configurations that were considered included modified CH-47 Chinooks (ACH-47s) armed with multiple guns, cannons, rockets and grenade launchers although these proved to be too cumbersome for use in the field.
In 1967 the US Army fielded that AH-1 Cobra, a dedicated gunship. Based around the UH-1 powerplant, the cobra had a much thinner profile, increased armor, speed and firepower. It proved to be highly effective in action against the NVA and Viet Cong.

MI-8 troop transport coverted to a gunship with the addition of rocket pods

The Soviets went through a similar evolution in their development of helicopter gunships as their US rivals. Starting with adding rockets and machine guns to MI-8 troop transports, they soon progressed to a dedicated design - the Mil MI-24 Hind. Both of these gunships would be used in many a battle in various third world conflicts, mostly in the infantry support role.
With the gunship concept now battle-proven, more advanced attack helicopters were developed in the late 70s/early 80s. The US fielded the Ah-64A Apache and upgraded AH-1 Cobras whilst the Italians developed the A129 Mangusta. These attack helicopters were designed with a confrontation with the Soviet Union in mind. It was hoped that their advanced avionics and anti-tank missiles would counteract the Warsaw Pact's overwhelming numeric superiority on the battlefield.
When the Soviet Union crumbled at the end of the 80s, the need for gunships may have been in doubt. 1991's Gulf War put any doubts to rest as fleets of Apaches and Cobras decimated Iraq armor in the open desert. Once again the concept had proven itself.
The terrorist attacks of September 11th, 2001 and the resulting war in Afghanistan took helicopter gunships into battle once again. The Apache, already proven in the anti-armor role now distinguished itself in the infantry support role as Coalition forces would frequently call the gunships in to attack Taleban forces.
The US-led invasion of Iraq in 2003 saw the Apache helicopter deployed once again although this time the battles were a little less one-sided as before. When the Apaches went into combat over populated areas with lots of cover for ground troops to lurk in they were less effective than when over the open desert. Coordinated ground fire downed or severely damaged several Apaches causing them to abort missions. Despite these setbacks, when deployed against Republican Guard divisions positioned out in the open, the Apaches once again proved to be a devestating weapons plafform.