Rotary threshing and separation unit

A rotary threshing and separation unit, comprising a rotor housing (12) with a feeding zone, a separation zone and a discharge zone, parts of the circumferential housing being closed and other parts having openings, a threshing and separation rotor (16) arranged in said rotor housing, beater plates fixed on said threshing and separation rotor, main sucking air flow stream generating means (18) sucking a main air flow stream through the rotor housing, and auxiliary air flow stream generating means (18) sucking an auxiliary air flow stream through a space underneath the sieve means and baffle plates arranged in the space underneath the sieves, is disclosed. To improve the separating function of the baffle plates, it is suggested to releasably fix at least one baffle plate to the threshing and separation unit. Also disclosed is a grain loss sensor (44) fixed on a baffle plate (36) and an electronic control device (46) that adjusts the setting of at least one baffle plate.