Tesla Patents 'Electric Fan Car' With Four Ducted Fans Ahead of Roadster Reveal

Tesla was just granted a patent for an “Electric Fan Car,” a system that uses four electric ducted fans in the rear diffuser to suck the car down to the road at any speed. The car in the drawings is a Model S, which Tesla stopped building in April.

It’s Tesla’s second fan car patent in just over a year, and it arrives two weeks before the company’s latest attempt at a Roadster demo.

Four fans in the diffuser

The USPTO granted US 12,746,987 B1 today. Tesla filed it in January 2024, but it goes back to a provisional application from January 17, 2023. Eight inventors are listed, and all but one are based in the Los Angeles area, where Tesla has its design studio in Hawthorne.

The idea is simple. An inlet on the underbody, between the rear wheels, feeds a duct that sweeps up to a wide outlet in the rear diffuser. Four axial fans sit side by side in that outlet, split by three vertical strakes. When they spin up, they evacuate the air under the floor and exhaust it through the rear.

That creates what Tesla calls a “suction region” under the floor. A vacuum. The rear end also gets a raked plate that acts as a second diffuser.

Tesla’s pitch is about speed independence. The filing notes that passive diffusers limit downforce at low speed and “often results in an excessive load at a high speed.” The fans, according to Tesla, “can produce a downforce independent of the vehicle velocity,” which helps with braking stability and cornering speed.

There’s one clever detail. A second version adds two smaller side inlets behind the main one, because Tesla says the central inlet tends to pull air forward from behind the car instead of from under the floor. That backwash adds no downforce, and Tesla says the fans end up “wasting power” on it.

Power comes from the same high-voltage pack that drives the wheels, so there’s no separate motor or battery for the fans, and they’re tied into the car’s control system. The driver can switch them on with a button, or the car can do it automatically at certain speeds.

Drawn on a car Tesla doesn’t make anymore

You can’t miss the Model S in these drawings. The fastback roofline, taillights, lip spoiler and door handles are all there.

In early 2023, when Tesla filed the provisional, that made sense. The Model S Plaid was Tesla’s performance flagship, and a fan-assisted track version would have been a fun halo. But Tesla ended Model S and Model X production in April after 14 years, and it’s turning the Fremont line over to Optimus. So that’s not happening.

Which leaves the Roadster, the only performance car Tesla still has in the pipeline. Last week, we reported on a Tesla patent for a hidden active rear wing good for up to 700 kg of downforce, drawn on a car that looks just like the new Roadster. And in August 2025, Tesla got another fan car patent using underbody fans and deployable skirts. Fans plus an active wing is a full track aero package, and the Roadster is the only car left to put it on.

Fan cars are nothing new

None of this is new. Chaparral raced the 2J in 1970 with two fans driven by a separate snowmobile engine. Brabham’s BT46B won the 1978 Swedish Grand Prix with Niki Lauda and was withdrawn right after. Gordon Murray put a 400 mm fan on the back of the T.50 road car.

And on the electric side, McMurtry has been doing it for years. Its Spéirling smashed the all-time Goodwood hill climb record in June 2022, about seven months before Tesla filed its provisional. It makes 2,000 kg of downforce at a standstill, has driven upside down, and McMurtry started production of the $1.36 million Spéirling PURE earlier this year. Its fans also run off the main battery.

Tesla’s main twist is that its design doesn’t need skirts sealing the car to the ground. The filing says the fans can work “without use of additional elements below the vehicle,” and packages them into a normal-looking diffuser.

Electrek’s Take

It’s a neat patent, but electric fan cars exist; they’re on sale, and McMurtry got there first by a wide margin. Putting the fans in the diffuser without skirts is a packaging choice. And without skirts, it’s hard to see Tesla getting anywhere near the 2,000 kg the Spéirling makes.

The Model S drawings say more than the claims do. Somebody at Tesla was clearly working on a track-focused Model S in 2023. That car is dead, and the idea has nowhere to go but the Roadster. Between this, last year’s skirted fan patent, and last week’s 700 kg wing, Tesla has built up a real track aero toolbox. That’s a lot more useful than making a car hover on SpaceX thrusters.

But patents aren’t products, and Tesla patents plenty of things that never ship. The Roadster was unveiled in 2017, promised for 2020, and is now slated for “2027 or 2028” with a demo pushed to October 15. If it finally shows up with fans in the back, great. We’d take that over a hover stunt any day.

Will we see fans on October 15, or just thrusters?

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