Tesla received patent 12,746,987 B1, titled “Electric fan car,” on September 29, 2026. The B1 designation marks a granted patent rather than a pending application, and it covers a rear diffuser in which electric ducted fans pull air out from under the car and push it backward, producing downforce that does not depend on how fast the car is moving.
In the patent’s own language, as quoted by Electrek, the fans “can produce a downforce independent of the vehicle velocity.” That sentence is the reason the filing drew attention: a car that presses itself into the road while standing still is a trick from the history of racing, and it has been prohibited in competition for decades.
Four fans in the rear diffuser, fed from beneath the floor
Electrek’s read of the document describes four axial electric ducted fans in the rear diffuser, separated by three vertical strakes. An inlet beneath the car, between the rear wheels, feeds a duct that leads to the fans, and the airflow creates a low-pressure “suction region” under the floor. A second version adds two smaller side inlets so the fans do not pull air forward from behind the car.
The fans run off the same high-voltage pack that drives the wheels, with no separate motor or battery, according to Electrek. The driver can switch them on, or the car can engage them automatically at set speeds. Carscoops, which linked the patent PDF in its own report and described the grant as taking place on September 29, lists the same parts, and adds a note on speed: the downforce is described as available at any speed, including a standstill. It names the components as an underbody inlet, a larger rear outlet, ducted fans and strakes between adjacent fans, with the claimed advantage that large spoilers are not needed and extra drag is limited.
The “under the body” part of the design is therefore split in two. The air is gathered from beneath the floor between the rear wheels, but the fans themselves sit at the back, in the diffuser, where the ducted air leaves the car. Electrek’s description of the suction region is the mechanism: air removed from beneath the floor lowers the pressure there, and the car is pushed down by the air above it.
Filing history and the car in the drawings
TeslaNorth reports that application 18/415094 was filed on January 17, 2024, with a provisional filing dated January 17, 2023, and names Niccolo Cymbalist as the lead inventor. Electrek counts eight inventors in total, all but one based in the Los Angeles area. Tesla is the assignee.
The drawings depict a Model S, a car Tesla stopped building in April 2026, and not the Roadster that the timing of the grant invites readers to assume. Carscoops notes that the drawings show a Model S and that the claims are not limited to one model, and that nothing in the patent confirms production. Electrek links the grant to the Roadster, which it says is slated for “2027 or 2028” and whose latest demonstration has been pushed to October 15.
It is also not Tesla’s first fan-car filing. Electrek describes this as the company’s second in a little over a year, after one in August 2025, so the idea has now produced two issued or pending documents from the same company in about thirteen months, each of which is a primary record of what Tesla’s engineers have put on paper.
Tesla has not commented on the filing in the coverage reviewed.
The racing ancestors that ended in bans
The concept has two famous precedents. The Chaparral 2J raced in the 1970 Can-Am season with two fans at the rear driven by a separate two-stroke twin-cylinder engine, while Lexan side skirts sealed against the ground to hold a low-pressure zone beneath the car. The Sports Car Club of America outlawed it after that season, after rival teams argued the fans were movable aerodynamic devices and complained about debris thrown at chasing cars.
The Brabham BT46B followed in Formula One. Niki Lauda won the 1978 Swedish Grand Prix at Anderstorp with it by more than half a minute, though Brabham described the fan as a cooling device, and the sport’s governing commission declared fan cars illegal afterward. The win stood because the car was not illegal when it raced.
Tesla’s version differs from both on a point that matters for road cars: the fans take power from the traction battery, so no second engine is needed. Whether that arrangement could meet road-legal and competition rules is not addressed in the patent coverage reviewed. The only production claim anywhere in the record is Electrek’s report that McMurtry already sells an electric fan car, the Spéirling, with about 2,000 kg of downforce at a standstill, which makes Tesla’s patent a claim on a design and not on the idea of the fan car itself.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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