Originally named the  "Iroquois", this is also known as a "Huey".  The nickname "Huey" comes from the shortening of "Helicopter-Utility-One".   These military helicopters were used during the Korea and VietNam eras for transporting wounded soldiers.  This helicopter in the photo is a "Mike" version - an upgrade of the "Charley" model with the Lycoming L-13 engine with 1300 RPM's of shaft horsepower.  There were only 767 "Charley" model helicopters made, and only a portion of those were retrofitted into the "Mike" model.  This survivor finds its home in the Heartland Museum of Military Vehicles, Lexington, NE. 

Photo by Kent Mallette (NE)