One or two large fins or strakes are sometimes positioned under the rear fuselage or below the empennage, to provide adequate stability at high angles of attack when the tail fin is shielded from the main airstream by the fuselage and/or the wing wake.
Anti-spin leading edge strakes, or spin strakes, or antispin fillet [REF] may be placed at the tailplane roots of generally aerobatic aircraft, such as the de Havilland Tiger Moth (British version), Scottish Aviation Bulldog, de Havilland Canada DHC-1 Chipmunk [REF].