In 1965, throughout the Vietnam war, the outstanding load capability associated with the CH-47 Chinook led the U.S. Army to request a heavily armed version to provide help for the AH-1 Cobra. The very first journey happened on 6th November of the same year and, in May 1966, four types of these heavy Chinooks, assigned on 1st Air Cavalry Division, were stationed during the An Khe base for trials. Because of heavy armaments, including a 40 mm XM-5 grenade launcher, two 20 mm M-24 cannon, five 12.7 mm M-2 machine guns and two hook-up points for rocket launchers or other loads-plus heavy armour to shield both crew and helicopterthe ACH-47 proved impressive in a ground troop support role. Nonetheless, due to the complexity associated with the aircraft together with pushing requirement for transport variations of the Chinook, the U.S. Army halted any more development.
