For the Mark II variant of the Supermarine Spitfire British fighter plane of World War II , see Supermarine Spitfire ( early Merlin powered variants ) .
This article is about a prototype American helicopter of the 1970s .
For the Mark II variant of the Supermarine Spitfire British fighter plane of World War II , see Supermarine Spitfire ( early Merlin powered variants ) .
This article is about a prototype American helicopter of the 1970s .