sorry that was supposed to say, Constant Rotor Speed. The massey has a hydraulic motor running the rotor and some how they can set the rotor to run a constant speed. like our Gleaner if the engine pulls down the rotor slows down, in the massey it just keeps on pluggin along adding capacity. If you set it for 700 rpms, is stays real close to where you set it, unless of course you plug it. The hydraulic rotor drive really works alot better than I would have even dreamed. I think Agco picked up a good combine when they bought massey