A small lipped extension on the trailing edge of a trunk lid, named for its resemblance to a duck tail. Used on classic Porsche 911 RS variants.
Ducktail is a small lipped extension on the trailing edge of a car trunk lid (or hatch). The shape resembles a duck's tail when viewed from the side. The most famous application is the 1973 Porsche 911 Carrera RS 2.7, which used a sharp ducktail as part of its aerodynamic package. The shape became iconic and has been referenced on subsequent 911 generations and on aftermarket kits for many other cars.
The ducktail serves a practical aerodynamic function: it disrupts airflow at the rear of the car, reducing rear lift at high speeds. Compared to a full wing, the ducktail is more subtle and integrated into the body shape. The 1973 RS 2.7 design was developed for high-speed touring car racing where rear stability was critical at speed.
Modern production cars with ducktail-style rear designs include the Porsche 911 ST (modern variants), the Mercedes-AMG GT Black Series, and various tribute kits available for older 911 generations. Ducktail-style aftermarket parts are popular in the air-cooled Porsche modification community.