The Porsche Ducktail: Engineering, Patent, and Legacy

From Porsche Newsroom: how the 1972 911 Carrera RS 2.7 ducktail cut rear lift (0.29 to 0.08 CL), gained 4.5 km/h, and became a 911 icon. Read more in detail.

Ducktail is one of those rare automotive details that starts as a joke, looks like provocation, and turns out to be pure engineering. In the early 1970s it appeared on the rear of the Porsche 911 Carrera RS 2.7—and the first reaction inside Porsche was far from unanimous. Designers were stunned to see the 911’s clean, simple shape interrupted by a wedge-like add-on on the engine lid. Sales experts, tasked with moving 500 cars worldwide, reportedly doubted they would sell more than a hundred. That mix of criticism and surprise helped produce the nickname that stuck: ducktail, a nod to the elongated rear of a waddling waterfowl.

Behind the visual drama sat a very practical problem tied to the aerodynamic reality of the era. Tilman Brodbeck, an aerospace engineer who joined Porsche in October 1970 and worked with Hermann Burst on the now-legendary part, described it in straightforward terms: the 911—like many cars then—was essentially shaped like a wing, flat underneath, curved on top, and tapering to a point at the back. A shape like that creates lift. And lift was the last thing the 911 needed, because excessive lift reduced performance and prevented the engine and chassis from being exploited to their full potential.

What followed was wind-tunnel logic, not mythology. Porsche’s wind-tunnel work revealed how enormous the rear lift coefficient was: 0.29 CL. The solution came in the form of a Gurney flap. In a strikingly fast development move, a roughly made spoiler—built from welding wire and thin sheet metal on the engine lid—reduced the figure by two-thirds to 0.08 CL after just two days of testing. The work also improved the drag coefficient value as described in the text as a measure of aerodynamic performance, and it increased top speed by 4.5 km/h to 240 km/h. On paper that gain might sound modest, but for an RS built with motorsport in mind, every fraction matters—and the results were enough to silence most remaining critics.

The ducktail’s “birth certificate” is not only cultural but also legal. Porsche notes that it was recorded in patent application number 2238704, submitted to the German Patent and Trade Mark Office on August 5, 1972. That single line ties the legend to a date, a filing, and an engineering trail you can point to.

Then something rare happened: a technical fix became culture. According to the same Porsche account, fans quickly went wild for both the fast lap times and the rear spoiler—an absolute novelty in the world of series-production cars. The wedge at the back turned into a signature, and the ducktail became an iconic part of the 911 story: criticized at first, celebrated later, and remembered ever since.

And it's not just a historical artifact.  The modern Porsche 911 Sport Classic (992), like the production car produced by utinogo, occupies 1,250 places in the world. As a crossover for the 911 (991, 2013-2016), the original Porsche Sport Design “Ducktail” car is also offered, featuring streamlined design and dynamics at the dealer. Taken together, these details point to an unchanging pattern: when a shape becomes a symbol, it returns in the form of carefully designed waves — sometimes as a statement of limited production, sometimes as an official sign of attention from owners who need this silhouette.

If a conclusion is warranted without guessing, it’s this: ducktail has lasted because it convinces in two languages at once—numbers from a wind tunnel and the instant recognition of a profile. It began as a controversial wedge, became a performance tool with documented aerodynamic gains, earned its place in a patent filing, and ultimately turned into a signature Porsche keeps revisiting. That is what “for all eternity” looks like in automotive design: a part that solves a problem and tells a story.