US Army trials of the Bell 204 helicopter in 1955 lead to the development of the HU-1. Because of the initial designation the nickname Huey came about. It was soon realized that the HU-1 didn’t have the lifting power for heavy loads or room for enough troops so it was given a larger cabin, larger engine, a modified main rotor along with a few other improvements and re-designated the UH-1B. Later versions of the UH-1B received an even more powerful engine. There were 1,010 “B” variants delivered to the US Army.
There were 766 Bell UH-1C helicopters built in several equipment modified variants. One was the “Frog” equipped with side-mounted XM-158 twin rocket pods each holding seven 2.75 inch rockets. The “M-5” fitted the gunship with a nose turret mounting an M-75 40 mm automatic anti-personnel grenade launcher that held 300 anti-personnel grenades. The crews referred to these as “Chunkers” because of the sound when the grenades were fired. The infamous “Shark” gunships were created in 1966 when permission was granted to use the fearsome looking “Tiger Mouth” on the front of the Hueys.