An unmanned air vehicle comprises a fuselage that defines aerodynamic flight surfaces, an engine mounted to the fuselage having an engine shaft arranged to rotate about a longitudinal axis with respect to the fuselage, and a propeller mounted to the engine shaft so as to rotate to thereby provide thrust. The aircraft also comprises a gyroscopic stabilization member coupled to the shaft such that rotation of the engine shaft results in rotation of the gyroscopic member. Thus, there is more stability during the entire flight envelope. In one embodiment, the gyroscopic stabilization member is comprised of a ring that is attached to the outer ends of the blades of the propeller and the ring is also selected so as to have a mass that will result in the gyroscopic stabilization member having a sufficient angular momentum so as to gyroscopically stabilize the aircraft.