New Holland CR10.90 Revelation harvesting rice - YouTube
https://www.youtube.com/watch?v=zTdriU3gFQk

2.7mph = 4345.23 m/h
30 ft = 9.144 m
4345.23 m * 9.144 m = 39732.7831 m^2
= 3.97327831 ha/h