Mc Culloch MC-4
The McCulloch Model MC-4 was an American tandem-rotor helicopter and was the first helicopter developed by McCulloch Aircraft Corporation, a division of McCulloch Motors Corporation. It was evaluated by the United States Army as the YH-30 and the United States Navy as the XHUM-1.
Read more about Mc Culloch MC-4: Design and Development, Variants, Operators, Survivors, Media, Specifications (YH-30)