Occasional Aviator, the Boeing Vertol model 107
IS the phrog. Vertolnut was using some sort of poetic license to imply otherwise. The point remains, the production military 107 far precedes the commercial production 107, especially those like N-192CH which were license built in Japan in 1967.
As to the whens and wheres of tandem rotor development: the US Piasecki company made the worlds first sucessful tandem rotor helicopter in 1945,
http://www.piasecki.com/xhrp-x.htm
the first production transport helicopter in 1947,
http://www.piasecki.com/hrp-1.htm
and the worlds first sucessful tandem overlapped rotor helicopter in 1948, along with the first sucessful helicopter autopilot system in 1950
http://www.piasecki.com/xhjp-1(h.htm
Willy waved, now in stowed for flight position.