Report KD 678 has been reviewed totally. The previous rotor had three separate spokes but it was expected that it is difficult to make the hole pattern in these spokes accurately enough to guarantee an exact angle of 120° in between the three blades. So the new rotor has a hub plate made out on one piece of 1.5 mm stainless steel sheet. The blades are made longer to minimise the dimensions of the hub plate. This rotor has a higher maximum Cp, a higher starting torque coefficient and it also looks better.