1987/ 1988: Duetz- Allis introduces the R40, R50, R60, and R70 Gleaner combines. The "R40" is the first class 4 Gleaner Rotary combine produced, and could run corn heads up to 6 rows. The new R0 series Gleaners are now running Duetz Air cooled Diesel engines. 1990: The Gleaner R0 series Gleaners are upgraded to the "Hawk" …