Remote-Controlled Hypercar Slices Through Air

Almost all entry-level physics courses, and even some well into a degree program, will have the student make some assumptions in order to avoid some complex topics later on. Most commonly this is something to the effect of “ignore the effects of wind resistance” which can make an otherwise simple question in math several orders of magnitude more difficult. At some point, though, wind resistance can’t be ignored any more like when building this remote-controlled car designed for extremely high speeds.

[Indeterminate Design] has been working on this project for a while now, and it’s quite a bit beyond the design of most other RC cars we’ve seen before. The design took into account extreme aerodynamics to help the car generate not only the downforce needed to keep the tires in contact with the ground, but to keep the car stable in high-speed turns thanks to its custom 3D printed body. There is a suite of high-speed sensors on board as well which help control the vehicle including four-wheel independent torque vectoring, allowing for precise control of each wheel. During initial tests the car has demonstrated its ability to¬† corner at 2.6 lateral G, a 250% increase in corning speed over the same car without the aid of aerodynamics.

We’ve linked the playlist to the entire build log above, but be sure to take a look at the video linked after the break which goes into detail about the car’s aerodynamic design specifically. [Indeterminate Design] notes that it’s still very early in the car’s development, but has already exceeded the original expectations for the build. There are also some scaled-up vehicles capable of transporting people which have gone to extremes in aerodynamic design to take a look at as well.

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A cardboard wind tunnel

Optimize Your Paper Planes With This Cardboard Wind Tunnel

We at Hackaday are great fans of hands-on classroom projects promoting science, technology, engineering and math (STEM) subjects – after all, inspiring kids with technology at a young age will help ensure a new generation of hardware hackers in the future. If you’re looking for an interesting project to keep a full classroom busy, have a look at [drdonh]’s latest project: a fully-functional wind tunnel made from simple materials.

A styrofoam car model in a cardboard wind tunnelBuilt from cardboard, it has all the same components you’d find in a full-size aerodynamics lab: a fan to generate a decent stream of air, an inlet with channels to stabilize the flow, and a platform to mount experiments on. There’s even some basic instrumentation included that can be used to measure drag and lift, allowing the students to evaluate the drag coefficients of different car designs or the lift-generating properties of various airfoils. Continue reading “Optimize Your Paper Planes With This Cardboard Wind Tunnel”

High-Speed RC Car Needs A Flight Controller

The fastest ground vehicles on earth are not driven by their wheels but by an aircraft jet engine. At world record speeds, they run on an aerodynamic razor’s edge between downforce, which limits speed, and liftoff, which can result in death and destruction. [rctestflight] wanted to see what it takes to run an RC car at very high speeds, so he built a ducted-fan powered car with aerodynamic control surfaces and an aircraft flight controller.

This high-speed car is built on the chassis of a 1/14th scale RC buggy, powered by 4 EDF (electric ducted fans) mounted on a very long aerodynamic foam board shell. It also has an aircraft-style tail with elevons and rudders for stabilization and control at high speed using an ArduPilot flight controller. The flight controller is set up to stabilize in the roll and yaw axis, with only fixed trim in the pitch axis.

[rctestflight] got the car up to 71 MPH (114 km/h), which is fast for most RC cars but well short of the 202 MPH RC car speed record. It was still quite hard to keep in a straight line, and the bumpy roads certainly didn’t help. He hopes to revisit the challenge in the future with larger motors and high voltage batteries.

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Magnus-Effect RC Aircraft Is A Lot Harder Than It Looks

Conventional airfoil wings have come out on top for getting flying machines airborne over the last century, but there were a few other interesting designs that have come and gone. One of these is the Magnus effect plane, which makes use of the lift produced by a spinning cylinder. [James Whomsley] from [Project Air] decided to build one as a side project, but it ended up being a lot more challenging than what he initially suspected. (Video, embedded below.)

The Magnus effect achieved a bit of viral fame a few years when [How Ridiculous] dropped a basketball down a dam wall with some backspin. [James] T-shaped Magnus effect plane has a pair of spinning cylinders at the top to create lift, driven by a brushless motor using a belt. A second brushless motor with a propeller is on the center carbon fiber tube provides forward thrust, and a rudder provides yaw control. The battery is attached to the bottom of the tub for stability.

The very first flight looked very promising, but [James] quickly ran into a series of problems related to center of gravity, power, pitch control, and drag. After iterations of the build-crash-rebuild cycle, he ended up with larger motors and rudder, shorter “wings”, and a higher thrust motor position. This resulted in a craft still only marginally controllable, but stayed in the air for quite a while. Since the intention was never to turn it into a long-term project, James] called it a success to avoid more yak shaving, and continue work on his airboat and rocketplane.

If you are interested in building one of your own, he put all the findings of his experimentation in a short report. For more inspiration, check out the other Magnus effect plane we covered that used KFC buckets for the wings.

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Retrotechtacular: Discovering Aerodynamics With The Chrysler Airflow

When you think about it, for most of human history we’ve been a pretty slow bunch. At any time before about 150 years ago, if you were moving faster than a horse can run, you were probably falling to your death. And so the need to take aerodynamics into consideration is a pretty new thing.

The relative novelty of aerodynamic design struck us pretty hard when we stumbled across this mid-1930s film about getting better performance from cars. It was produced for the Chrysler Sales Corporation and featured the innovative design of the 1934 Chrysler Airflow. The film’s narration makes it clear why the carmaker would go through the trouble of completely rethinking how cars are made; despite doubling average engine horsepower over the preceding decade, cars had added only about 15% to their top speed. And while to our 21st-century eyes, the Chrysler Airflow might look like a bulked-up Volkswagen Beetle, compared to the standard automotive designs of the day, it was a huge aerodynamic leap forward. This makes sense with what else was going on in the technology world at the time — air travel — the innovations of which, such as wind tunnel testing of models, were spilling over into other areas of design. There’s also the influence of [Orville Wright], who was called in to consult on the Airflow design.

While the Airflow wasn’t exactly a huge hit with the motoring public — not that many were built, and very few remain today; [Jay Leno] is one of the few owners, because of course he is — it set standards that would influence automotive designs for the next 80 years. It’s fascinating too that something seemingly as simple as moving the engine forward and streamlining the body a bit took so long to hit upon, and yet yielded so much bang for the buck.

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A Look At The Most Aerodynamic Cars Ever Built

Whether gasoline, diesel, or electric, automakers work hard to wring every last drop of mileage out of their vehicles. Much of this effort goes towards optimising aerodynamics. The reduction of drag is a major focus for engineers working on the latest high-efficiency models, and has spawned a multitude of innovative designs over the years. We’ll take a look at why reducing drag is so important, and at some of the unique vehicles that have been spawned from these streamlining efforts.

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The Rise And Fall Of The Fan Car

The advent of aerodynamic wings in motorsport was one of the most dramatic changes in the mid-20th century. Suddenly, it was possible to generate more grip at speed outside of altering suspension setups and fitting grippier tyres. However, it was just the beginning, and engineers began to look at more advanced ways of generating downforce without the drag penalty incurred by fitting wings to a racecar.

Perhaps the ultimate expression of this was the fan car. Mechanically complex and arguably dangerous, the technology offered huge downforce with minimal drag. However, the fan car’s time in the spotlight was vanishingly brief, despite the promise inherent in the idea. Let’s take a look at the basic theory behind the fan car, how they worked in practice, and why we don’t see them on racetracks today. Continue reading “The Rise And Fall Of The Fan Car”