A propeller related vehicle in accordance with one embodiment of the present invention is described as a helicopter having an airframe housing a motor mechanism for powering a main propeller attached to a main drive shaft that extends vertically through the airframe and for powering a tail rotor. The helicopter further includes a horizontal stabilizing mechanism attached between the main propeller and the main drive shaft, which permits the main propeller to freely pivot about the main drive shaft independently from the airframe. As such when the main propeller is rotating and the main propeller begins to pitch, the rotating main propeller has a centrifugal force created by the rotation thereof and will tend to pivot about the horizontal stabilizing mechanism in a manner that offsets the pitch such that the helicopter remains in a substantially horizontal position. In addition various main propeller configurations may be employed that provide additional self-stabilization.