Abstract: An automatic lawn mower vehicle is of a tricycle construction having a forward drive-wheel assembly including a drive wheel and a drive-wheel motor, and having a trailing sulky connected at a sulky hitch end by a vertical hinge to the forward drive-wheel assembly. Steering is accomplished by a motor mounted to the drive-wheel assembly and through a gear reduction system connected to the sulky part of the vertical hinge. A plurality of grass cutters are mounted directly to the drive-wheel assembly for cutting in a horizontal plane however the vehicle may be turning. The outermost two cutters are equidistant from the drive wheel and are centered in the vertical plane of the drive-wheel axle. The grass cutting wake produced by this machine is always equally wide on both sides of any point in the path of the drive wheel, so that the predetermined drive-wheel path, e.g.