Wacky RC Fan Car Can Out-Accelerate the Tesla Roadster (That Doesn’t Exist Yet)

It draws inspiration from Gordon Murray’s Brabham BT46 F1 car.

byRob Stumpf|
Tesla News photo


The next-generation Tesla Roadster is one of the most hotly anticipated electric sports cars that may or may not ever make it to market. With a sub-two-second zero to 60 time, the Roadster is easily pushing the limits of just how fast street cars can rocket off the line. Obviously, that's going to attract a bit of competition.

What we didn't expect is for that competition to come from an RC car. As Gizmodo brought to our attention, YouTuber Engineering After Hours set out to best the Roadster's acceleration sprint in a tiny, custom-built radio controlled toy. The lessons he learned proved to be extremely useful in understanding exactly why achieving such crazy acceleration with street cars can be so difficult. For starters, besting the Roadster's claimed time required drawing inspiration from a controversial F1 car.

Engineering After Hours via YouTube

The upcoming Tesla Roadster is said to sprint from zero to 60 miles per hour in just 1.9 seconds. That's a rather ambitious time, though thanks to the help of modern electric propulsion systems, it seems within the automaker's grasp—whenever the car actually comes to market, that is. Meanwhile, Engineering After Hours set out to beat the time on a scaled version.

A custom designed RC car is the heart of this particular experiment, which is all about beating the 1.9-second figure. But doing that in a tiny version of a car is a lot harder than you think, and its low weight only adds to the problem.

As it turns out, keeping the car planted on the ground is pretty difficult. Even with all-wheel-drive and traction compound applied to the tires, the car had issues sticking to the pavement at takeoff. You might remember the classic clip of a Mercedes CLR piloted by Peter Dumbreck at the 1999 Le Mans doing a backflip—well, the RC car was doing something similar because of its own aerodynamics and weight.

The underside of the RC car., Engineering After Hours via YouTube

To solve the issue, the YouTuber drew inspiration from Gordon Murray, the same man who built the beloved McLaren F1. In the late '70s, Murray did some work for Brabham to help design a car that would beat the Lotus Type 78.

The Brabham BT46B was born, affectionately earning the "Fan Car" nickname thanks to the large fan mounted at the rear of the vehicle which, on the books, was to help cool the horizontally-mounted radiator. A rather convenient side effect was that it created an immense reduction in air pressure underneath the car, which was close to the ground thanks to a set of low-hanging skirts. This technicality helped circumvent the ban on "moveable aerodynamic devices" and helped the car maintain phenomenal grip around the track.

As you may have guessed by now, the RC car designed by the YouTuber uses very similar technology. Custom 3D-printed ducting houses two fans that suck air from underneath the car, effectively creating a vacuum that helps keep the tiny vehicle sucked to the ground. With the fans enabled, the roughly 7.9-pound RC car is able to generate around 19 pounds of downforce, a figure roughly 240 percent of the car's weight.

The fans enabled the car to sustain 3Gs of acceleration and cornering force. With the fans off, the car struggled to maintain anything over 1G in both acceleration and cornering force. After some trial and error (and lot of carnage), the car's best zero to 60 run took an astounding 1.73 seconds, beating the Tesla Roadster's supposed 1.9-second mark. When adjusting the time for a one-foot rollout (as Tesla does when measuring this time) the calculations point to about 1.46 seconds.

Despite the victory, the RC car did expose a fatal flaw that also forced Brabham to withdraw its fan car from the races. One of the biggest complaints by other drivers racing against the BT46B was that it would hurl rocks at cars behind it—it was this reason that the Fan Car was voluntarily withdrawn before it could be banned. This complaint has been long debated over its validity; however, as demonstrated in the YouTube video, the RC car kicked enough rocks up to actually shatter the protective lens of the GoPro attached to its rear.

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Now, he might have a little bit of work to do, because apparently Tesla is now targeting a 1.1-second zero to 60 time for the Roadster. Musk says that this will be possible using the SpaceX rocket thruster option package, something which isn't explained in a technical capacity, though he has also previously claimed that this would enable the Roadster to hover.

If nothing else, this video gives a great overview of why the auto industry is reaching a critical point in acceleration times, especially with cars like the Tesla Roadster pushing the limits.

Got a tip or question for the author? Contact them directly: Rob@TheDrive.com

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