“The Macchi M.C. 72 was an experimental seaplane designed and built by the Italian aircraft company Macchi Aeronautica. The M.C. 72 held the world speed record for all aircraft for five years. In 1933 and 1934, it set a world record for speed over water which still stands to this day.”
https://en.wikipedia.org/wiki/Macchi_M.C.72
Sleek.Fast.For a brief time it was the overall fastest. Aerodynamically is was similar to the American Navy and Army entrants.The Supermarine company ended up taking the cake a little later on.It`s model became the R.A.F.`s primary fighter during the Battle of Britain.Oddly enough,this aircraft was produced as late as 1948.
It would be interesting to see a diagram showing the propeller gearing.