Perhaps the most successful helicopter design used in the Vietnam War, the ACH-47A was a classified modification of the CH-47 Chinook helicopter used as a gunship from May, 1966 through February 1968. Not declassified until the late 1990's, the ACH-47A served first in the 53rd Aviation Detachment ("Guns-A-Go-Go") as an experimental deployment, then as the 1st Aviation Detachment (Provisional) of the 1st Cavalry's 228th ASHB (Keeping the same unit nickname). Only four of these aircraft were produced by the Boeing/Vertol company. These were Easy Money, Birth Control, Co$t of Living, and Stump Jumper. Onboard armament consisted of one M75 40mm grenade launcher, one M24A1 20mm cannon and either two M2 .50cal machine guns ("Ma Deuce") or two M60 7.62mm machine guns. Outboard armament consisted of either M18 gun pods holding M134 7.62mm miniguns or XM159 19-tube 2.75 inch rocket launchers. Other modifications to the standard CH-47 airframe included heavier armour and the weapon systems' associated electronics. Unique among the U.S. Army's attack helicopters, this is the only design that successfully destroyed every target it was assigned without fail. Only one example of this helicopter survives (Easy Money), the others being destroyed either in accidents or by enemy action.