The next generation Tesla Roadster is one of the most anticipated electric sports cars that may or may not make it to market. With a time from zero to 60 seconds under two seconds, the roadster easily reaches the limits of how fast street cars can shoot off the line. That will of course attract a bit of competition.
What we didn’t expect is that this competition would come from an RC car. When Gizmodo brought this to our attention, YouTuber Engineering After Hours set out to improve the roadster’s acceleration sprint in a tiny, purpose-built radio-controlled toy. The lessons he learned have proven extremely useful in understanding exactly why it can be so difficult to get such crazy acceleration in street cars. To shorten the time taken by the roadster, you first had to take inspiration from a controversial F1 car.
The upcoming Tesla Roadster will sprint from zero to 60 miles per hour in just 1.9 seconds. It’s a pretty ambitious time, though thanks to the help of modern electric propulsion systems, it seems to be within reach for the automaker – when the car actually hits the market. In the meantime, Engineering After Hours set out to beat time with a scaled version.
A specially developed RC car is at the heart of this special experiment, the aim of which is to beat the 1.9 second figure. But doing that in a tiny version of a car is a lot harder than you think, and its light weight only adds to the problem.
As it turns out, keeping the car on the ground is quite difficult. Even with all-wheel drive and traction mass applied to the tires, the car struggled to stick to the sidewalk when it started. You may remember the classic clip of a Mercedes CLR that was piloted by Peter Dumbreck at Le Mans in 1999 and did a backflip – well, the RC car did something similar because of its own aerodynamics and weight.
To solve the problem, the YouTuber took inspiration from Gordon Murray, the same man who built the beloved McLaren F1. In the late 1970s, Murray worked for Brabham to design a car that would beat the Lotus Type 78.
The Brabham BT46B was born and was affectionately nicknamed the “Fan Car” thanks to the large fan at the rear of the vehicle, which should help cool the horizontally mounted radiator in the books. A very practical side effect was that the air pressure under the car, which was close to the floor thanks to a set of low-slung skirts, was reduced immensely. This technique helped circumvent the ban on “moving aerodynamic devices” and helped the car maintain phenomenal grip on the track.
As you may have guessed, the RC car youTuber designed uses very similar technology. Custom 3D printed ducts house two fans that draw in air from under the car, effectively creating a vacuum that helps keep the tiny vehicle sucked in on the ground. When the fans are activated, the roughly 7.9-pound RC car can produce around 19 pounds of downforce, which is roughly 240 percent of the vehicle’s weight.
The fans allowed the car to maintain 3G acceleration and cornering power. With the fans off, the car tried to keep both acceleration and cornering force above 1G. After some trial and error (and a lot of carnage), the car’s best run from zero to 60 took an astonishing 1.73 seconds, beating the Tesla Roadster’s alleged 1.9 second mark. When adjusting the time for a rollout by one foot (like Tesla measured that time) the calculations point to about 1.46 seconds.
Despite the victory, the RC car revealed a fatal flaw that also forced Brabham to withdraw his fan car from the races. One of the biggest complaints from other drivers who competed against the BT46B was that it would throw rocks at cars behind it – for this reason, the fan car was voluntarily withdrawn before it could be banned. This complaint has long been debated about its validity; As shown in the YouTube video, however, the RC car threw up enough stones to actually break the protective lens of the GoPro attached to the back.
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