Abstract: A rear discharge mower deck has at least two cutting blades mounted on vertical spindles in cutting chambers, a fan in a housing mounted on the deck over the cutting chambers, and an inlet opening between the cutting chambers and the fan housing. The surface area of the inlet opening may be between about 50% and about 80% of the surface area within the fan diameter. A stripper plate may be on one edge of the inlet opening, and each cutting chamber may have an upwardly sloping tunnel to the inlet opening.

Abstract: A rear discharge mower deck has at least two cutting blades mounted on vertical spindles in cutting chambers, a fan in a housing mounted on the deck over the cutting chambers, and an inlet opening between the cutting chambers and the fan housing. The surface area of the inlet opening may be between about 50% and about 80% of the surface area within the fan diameter. A stripper plate may be on one edge of the inlet opening, and each cutting chamber may have an upwardly sloping tunnel to the inlet opening.

Abstract: A convertible mower deck which, in one embodiment, encloses the blade when it is in a mulching mode is provided. In a discharge mode, the deck provides one or more gaps, troughs or ducts through which cut material clippings can escape. The deck is convertible convert to a rear discharge mode by removal of a plug or insert that extends along the rear of the cutting chamber walls of the deck. The plug or insert is configured to seat into a slot, windfoil or ridge provided in the deck. A quick connect fastener at one end secures the plug to the deck. The ridge, windfoil or slot is flared outwardly and/or downwardly to provide a discharge opening. Because the material clippings in a discharge mode are permitted to exit through the opening(s) before they impact a mulch ramp deflector (on the underside of the mower deck or on the blade) the clippings “leak” out the opening and onto the top of the lawn or into a bag.