Prop-Driven Cardboard RC Car Doesn’t Skimp On Performance

August 25, 2020 by Donald Papp 17 Comments

[Kryzer Channel] takes making a DIY RC car to a whole new level with this prop-driven electric car that is made almost entirely out of cardboard (YouTube video, also embedded below.) By attaching an electric motor with a push prop to the back of the car, [Kryzer] avoids the need for any kind of drive system or gearing. Steering works normally thanks to some scratch-built linkages, but the brake solution is especially clever.

Braking is done by having a stocky servo push a reinforced stub downward, out of a hole in the center of the car. This provides friction against the road surface. After all, on an RC car a functional brake is simply not optional. Cutting the throttle and coasting to a stop works for a plane, but just won’t do for a car.

Winding thread around metal components then saturating with CA glue makes a durable assembly.

Layers of corrugated cardboard and hot glue make up the bulk of the car body, and some of the assembly techniques shown off are really slick and make the video really worth a watch. For example, the construction of the wheels (starting around 2:24) demonstrates making them almost entirely out of cardboard, saturated with CA glue for reinforcement, with a power drill acting as a makeshift lathe for trimming everything down. A section of rubber inner tube provides the tire surface and a piece of hard plastic makes a durable hub. Wraps of thread saturated in CA glue, shown here, is another technique that shows up in several places and is used in lieu of any sort of fasteners.

The well-edited video (embedded below) is chock full of clever assembly and construction. Unsurprisingly, this is not [Krazer]’s first cardboard vehicle: their video channel has other impressive cardboard models and racers to show off.

Continue reading “Prop-Driven Cardboard RC Car Doesn’t Skimp On Performance” →

How To Get Into Cars: Aero Mods For More Grip

August 19, 2020 by Lewin Day 32 Comments

In 1960, Enzo Ferrari said “Aerodynamics are for people who can’t build engines”. It’s a quote that’s been proven laughably wrong in decades since. Aerodynamics are a key consideration for anyone serious about performance in almost any branch of motorsport. Today, we’ll take a look at how aero influences the performance of your car, and what modifications you might undertake to improve things.

Gains To Be Had

Improving the aerodynamics of your vehicle can mean wildly different things, depending on what your end goal is. Aerodynamics affects everything from top speed, to fuel economy, to grip, and optimizing for these different attributes can take wildly different routes. Often, it’s necessary to find a balance between several competing factors, as improvements in one area can often be detrimental in another.

To understand aerodynamics with regards to cars, we need to know about the forces of lift (or downforce), and drag. Drag is the force that acts against the direction of motion, slowing a vehicle down. Lift is the force generated perpendicular to the direction of motion. In the context of flight, the lift force is generated upwards with respect to gravity, lofting planes into the air. In an automotive context, we very much prefer to stay on the ground. Wings and aerodynamic surfaces on cars are created to create lift in the opposite direction, pushing the vehicle downwards and creating more grip. We refer to this “downwards lift” as downforce.

Continue reading “How To Get Into Cars: Aero Mods For More Grip” →

Ford’s Powershift Debacle

June 3, 2020 by Lewin Day 203 Comments

In the automotive world, change is a constant, and if you’re not keeping up, you’re falling behind. New technologies and methodologies are key to gaining an edge in the market, and companies invest billions each year trying to find the next big thing, or even the next minor incremental improvement.

In just such a quest, Ford Motor Company decided to explore an alternative to the traditional automatic gearbox, aiming for greater fuel efficiency in their small cars. On paper, there were gains to be had. Unfortunately, not everything went according to plan. Continue reading “Ford’s Powershift Debacle” →

Losing A Wheel On Your Commute; 3-Wheelers Vie For The Open Road

May 27, 2020 by Jenny List 76 Comments

We live at an interesting point in time for the technologically minded motor vehicle enthusiast, and we stand on the brink of a major directional shift in how we imagine a car. Within ten years it’s likely that the electric motor will have moved from an extravagance or a fringe choice to a mainstream one, and a piston engine will be the preserve of an ever smaller niche market.

The Electrameccanica Solo three-wheeler car.

Along the way is it possible that the very form factor of an automobile will change, or will cars in decades hence have the same basic shape as those we’re used to? The Canadian company Electrameccanica certainly think so, because they’ve launched a refreshingly different take on commuter transport for one. Their Solo is a three-wheeler car, with two wheels at the front and one trailing wheel at the back configuration. It’s a bold design, but if it’s such an obvious one then why don’t we drive three-wheelers already?

It’s time to examine a few of the properties of a three-wheeler, and along the way visit some of the past attempts at this configuration.

Continue reading “Losing A Wheel On Your Commute; 3-Wheelers Vie For The Open Road” →

Wall-Climbing Robot Grabs Prize

May 19, 2020 by Bryan Cockfield 24 Comments

Gravity is a nice thing to have most of the time, but sometimes it would be nice to be able to ignore it for certain applications. Rock climbing, for example, would be much easier, as would performing bridge inspections in the way that a group of mechanical engineering cadets (students) at The Citadel, a military college in South Carolina, were tasked with doing. Frustrated with the amount of traffic backups that normal bridge inspections caused, they invented a robot that defies gravity, and won a $10k prize for their efforts.

The result is essentially an RC car with a drone built in, or looking at it another way it’s a drone with wheels. The car is able to drive on vertical surfaces to inspect the bridges by using its propellers to force itself onto the surface. The lack of complicated moving parts or machinery, like a cable suspension system or other contraption, makes this device exceptionally versatile for the task at hand, reduces the amount of time needed for inspections, and can do them more safely and without closing lanes of traffic. The group hopes to build a second prototype soon and present it to the Department of Transportation for approval for more widespread use.

The need for tools like these is in high demand now as well, especially in the United States where crumbling infrastructure is often not thought about, taken seriously, or prioritized. Even for bridges that aren’t major pieces of infrastructure, tools like these will prove to be very useful.

Thanks to [Ben] for the tip!

How To Get Into Cars: Nat Atmo Engine Mods

May 19, 2020 by Lewin Day 54 Comments

While the car world is obsessed with everything boosted these days, many still yearn for the smooth power delivery and sonorous tone of a naturally aspirated engine. Of course, everyone still wants to go fast, so here’s how you go about getting more power out of your car without bolting on a big turbo or whining supercharger.

Intakes: This Can Get Pretty Invovled

A modified intake installed on a Honda S2000. Also referred to as “cold-air intakes”, they aim to suck in air at lower temperature which helps produce more power – hence the shield between the air filter and exhaust.

The intake is one of the first modifications made by many budding car enthusiasts. Throwing on a chromed intake pipe with a big pod filter was the mod to have back in the Fast and Furious era. Power gains can be had, though typically these are minor – on the order of 5-10 horsepower at most. It all depends on the car in question. A BMW M5 V10 was designed for high performance, with a highly advanced intake with individual throttle bodies from the factory. It’s unlikely any eBay parts are going to unlock horsepower that BMW’s engineers didn’t already find. Conversely, early Mazda Miatas are known to have a restrictive intake, largely due to the flap-type air flow meter. Replacing this with a freer-flowing setup has merit.

Continue reading “How To Get Into Cars: Nat Atmo Engine Mods” →

Lock Your Keys In The Car On Purpose With Aluminum Foil

April 22, 2020 by Bryan Cockfield 74 Comments

[TJ] is a surfer, and drives his car to get to the beach. But when he gets there he’s faced with a dilemma that most surfers have: either put his key in your baggies (shorts) or wetsuit and hope it doesn’t get lost during a wipeout, or stash it on the rear wheel of his car. Hiding the keyfob by the car isn’t an option because it can open the car doors just by being in proximity to the car. He didn’t want to risk losing it to the ocean either, so he built a waveguide of sorts for his key out of aluminum foil that lets him lock the key in the car without locking himself out.

Over a series of trials, [TJ] found out that his car, a 2017 Chevy Cruze, has a series of sensors in it which can determine the location of the keyfob based on triangulation. If it thinks the keyfob is outside of the car, it allows the door to be locked or unlocked with a button on the door handle. If the keyfob is inside the car, though, it prevents the car from locking via the door handles so you don’t accidentally lock yourself out. He found out that he could “focus” the signals of the specific sensors that make the car think the keyfob is outside by building an open Faraday cage.

The only problem now is that while the doors can be locked, they could also can be unlocked. To solve that problem he rigged up an ESP32 to a servo to open and close the opening in the Faraday cage. This still means there’s a hidden device used to activate the ESP32, but odds are that it’s a cheaper device to replace than a modern car key and improves security “through obscurity“. If you have any ideas for improving [TJ]’s build, though, leave them in the comments below. Surfers across the world from [TJ] to the author would be appreciative.