Abstract: A hydrokinetic device comprising a fluid containing housing and unique relatively rotatable wheel means, including an impeller wheel connected to an input shaft and a turbine wheel connected to an output shaft. With the addition of a stator wheel the device may provide torque multiplication between the shafts, or without the stator may be used to couple the shafts together. The wheel means is sized and arranged so that in one sequential pair of wheels the entrance edge of one of the wheels is spaced apart from the exit edge of the adjacent wheel a distance generally equal to or greater than the smallest maximum width of one of the wheels, and so that the heads generated by rotation of the wheels are predominantly additive and do not cause potentially destructive negative counter heads opposing the impeller flow. The conical configuration of wheel means with parallel edges especially lends itself to achieving such desired arrangement.