A combine harvester (200, 300), comprising: a housing including a rear hood (224, 324) and opposite side walls (232, 332) which define an interior; a blower disposed in the interior of the housing, the blower configured to generate an air stream in a substantially rearward direction; a cleaning system disposed in the interior at a location rearward of the blower, the cleaning system separating residue from a crop material such that the residue is transported via the air stream rearwardly to be discharged from the housing (202, 302); a chopper rotor assembly (60, 204, 304) disposed within the interior and comprising a chopper rotor (74, 206, 306) mounted about a hub (208, 308) for rotation about an axis (210, 310) defined by the hub (208, 308) and a plurality of blades (212, 312) coupled to the hub (208, 308) of the chopper rotor (74, 206, 306) for chopping the residue as it is received via the air stream; a chopper housing (202, 302) disposed within the interior and defining an inlet opening (220, 320) for receiving the residue being transported via the air stream from the cleaning system and an outlet (222, 322) spaced rearward from the chopper rotor (74, 206, 306) for discharge of the chopped residue from the interior of the housing (202, 302); and a roof structure (226, 326) of the chopper housing (202, 302) located above the chopper rotor (74, 206, 306), the roof structure (226, 326) being disposed in close proximity to the chopper rotor (74, 206, 306) such that a minimally-sized gap (d) is defined therebetween; wherein, the air stream generated by the blower flows out of the interior via a flow path (238, 240, 340, 322) defined through the chopper rotor (74, 206, 306) without being substantially redirected from flowing in the rearward direction by the plurality of blades of the chopper rotor (74, 206, 306), wherein, due to the size of the gap defined between the roof structure and chopper rotor (74, 206, 306), the air stream flows through the chopper rotor (74, 206, 306) to be discharged from the interior without flowing above the chopper rotor (74, 206, 306) and through the gap (d), characterized in that the roof structure (226, 326) comprises a first section (234, 328) and a second section (236, 330) that converge to define a lowermost point and form a substantially V-shaped structure, wherein the gap (d) is defined between the lowermost point of the roof structure (226, 326) and the chopper rotor (74, 206, 306). a housing including a rear hood (224, 324) and opposite side walls (232, 332) which define an interior; a blower disposed in the interior of the housing, the blower configured to generate an air stream in a substantially rearward direction; a cleaning system disposed in the interior at a location rearward of the blower, the cleaning system separating residue from a crop material such that the residue is transported via the air stream rearwardly to be discharged from the housing (202, 302); a chopper rotor assembly (60, 204, 304) disposed within the interior and comprising a chopper rotor (74, 206, 306) mounted about a hub (208, 308) for rotation about an axis (210, 310) defined by the hub (208, 308) and a plurality of blades (212, 312) coupled to the hub (208, 308) of the chopper rotor (74, 206, 306) for chopping the residue as it is received via the air stream; a chopper housing (202, 302) disposed within the interior and defining an inlet opening (220, 320) for receiving the residue being transported via the air stream from the cleaning system and an outlet (222, 322) spaced rearward from the chopper rotor (74, 206, 306) for discharge of the chopped residue from the interior of the housing (202, 302); and a roof structure (226, 326) of the chopper housing (202, 302) located above the chopper rotor (74, 206, 306), the roof structure (226, 326) being disposed in close proximity to the chopper rotor (74, 206, 306) such that a minimally-sized gap (d) is defined therebetween; wherein, the air stream generated by the blower flows out of the interior via a flow path (238, 240, 340, 322) defined through the chopper rotor (74, 206, 306) without being substantially redirected from flowing in the rearward direction by the plurality of blades of the chopper rotor (74, 206, 306), wherein, due to the size of the gap defined between the roof structure and chopper rotor (74, 206, 306), the air stream flows through the chopper rotor (74, 206, 306) to be discharged from the interior without flowing above the chopper rotor (74, 206, 306) and through the gap (d), characterized in that the roof structure (226, 326) comprises a first section (234, 328) and a second section (236, 330) that converge to define a lowermost point and form a substantially V-shaped structure, wherein the gap (d) is defined between the lowermost point of the roof structure (226, 326) and the chopper rotor (74, 206, 306).