A drive suitable for powering a helicopter rotor, comprising a lubricating system; said lubricating system comprising, in turn,: - a lubricating pump; - a tank of lubricating fluid; and - a casing which houses a lubricated member of said drive; said lubricating pump comprising: - a first stage in turn comprising an intake connected hydraulically to said tank, and a delivery outlet connected hydraulically to a number of nozzles for feeding said lubricating fluid into said casing and onto said lubricated member; said first stage compressing, in use, said lubricating fluid from said tank to a pressure for supply to a lubricated member which is housed within said casing; and - a second stage in turn comprising an inlet connected, in use, hydraulically to an opening defined by said casing, and an outlet connected hydraulically to said tank; said second stage feeding said lubricating fluid in said first casing back into said tank; said second stage being a Roots type, and comprising a first and a second rotor (31, 32) rotating, in use, in opposite directions to feed said lubricating fluid from said inlet to said outlet; said first and said second rotor (31, 32) both being operated, in use, by said first stage; said first rotor comprising a number of first lobes and said second rotor comprising a number of second lobes; said first and second lobes (33, 34) having conjugate profiles in constant contact with one another; said first stage comprising at least a third rotor and fourth rotor connected functionally to said first and second rotor (31, 32) respectively; one of said third and fourth rotor (35, 36) being powered and rotating, in use, the other of said third and fourth rotor (35, 36); said pump further comprising: - a first shaft connecting said first and third rotor (31, 35); - a second shaft to which said second and fourth rotor (32, 36) are fitted; and - a housing which houses said first and second stage (5, 10); said housing comprising: - a first and a second body (21, 22) defining respective axial end of said pump; characterized in that said housing comprises three separate plates (23, 24, 25) axially interposed between said first and second body (21, 22) and separating said first and second body (21, 22) in fluidtight manner; said first body having a first cavity which faces first plate and houses said first and second rotor (31, 32); said second body having a second cavity which faces second plate and houses said third and fourth rotor (35, 36). - a lubricating pump; - a tank of lubricating fluid; and - a casing which houses a lubricated member of said drive; - a first stage in turn comprising an intake connected hydraulically to said tank, and a delivery outlet connected hydraulically to a number of nozzles for feeding said lubricating fluid into said casing and onto said lubricated member; said first stage compressing, in use, said lubricating fluid from said tank to a pressure for supply to a lubricated member which is housed within said casing; and - a second stage in turn comprising an inlet connected, in use, hydraulically to an opening defined by said casing, and an outlet connected hydraulically to said tank; said second stage feeding said lubricating fluid in said first casing back into said tank; - a first shaft connecting said first and third rotor (31, 35); - a second shaft to which said second and fourth rotor (32, 36) are fitted; and - a housing which houses said first and second stage (5, 10); - a first and a second body (21, 22) defining respective axial end of said pump;