The earlier "short-body" Hueys were a success, especially in the gunship role, but lacked the cabin space to be an effective troop transport. The US Army wanted a version that could carry a crew of four (two pilots and two door gunners) and also deliver an infantry section of eight-ten soldiers. Bell's solution was to stretch the UH-1B fuselage by 41 inches and use the extra space to fit two sideways-facing seats on either side of the transmission. This brought the total seating capacity to 15, including crew seats.

The new Huey was designated UH-1D by the US Army and as the Model 205 by Bell. The enlarged cabin could also accommodate six stretchers; double that of the earlier models, making the "Delta" a good MEDEVAC aircraft.

UH-1 "Huey" Iroquois Specifications