Transportation Hacks

1516 Articles

A Die-Cast Car Subframe, Pushing The Limit Too Far?

September 16, 2023 by 81 Comments

A piece of manufacturing news from Tesla Motors caught our eye, that Elon Musk’s car company plans to die-cast major underbody structures — in effect the chassis — for its cars. All the ingredients beloved of the popular tech press are there, a crazy new manufacturing technology coupled with the Musk pixie dust. It’s undeniably a very cool process involving a set of huge presses and advanced 3D-printing for the sand components of the mould, but is it really the breakthrough it’s depicted as? Or has the California company simply scored another PR hit?

We produced an overview of die casting earlier in the year, and the custom sand moulding in the Tesla process sounds to us a sort of half-way house between traditional die casting and more conventional foundry moulding. I don’t doubt that the resulting large parts will be strong enough for the job as the Tesla engineers and metallurgists will have done their work to a high standard, but I’m curious as to how this process will give them the edge over a more traditional car manufacturer building a monocoque from pressed steel. The Reuters article gushes about a faster development time which is no doubt true, but since the days of Henry Ford the automakers have continuously perfected the process of making mass-market cars as cheaply as possible. Will these cast assemblies be able to compete with pressed steel when applied to much lower-margin small cars? I have my doubts.

Aside from the excessive road noise of the Tesla we had a ride in over the summer, if I had a wish list for their engineers it would include giving their cars some longevity.

Header: Steve Jurvetson, CC BY 2.0.

A black race car with white text of sponsors moves across an asphalt surface. There is a blue wall and a green, grassy field in the background. The car has white and red stripes as well.

Students Set EV Acceleration World Record

September 14, 2023 by 29 Comments

Humans have a need for speed, and students from the Academic Motorsports Club Zurich (AMZ) have set a new acceleration record for an electric vehicle with a 0 to 100 km/h (0 to 62 mph) time of 0.956 seconds.

The mythen features four custom electric hub motors with a total output of 240 kW and a vehicle weight of 140 kg (309 lb) thanks to the use of carbon fiber and aluminum honeycomb. The car was able to get up to speed over only 12.3 m (40 ft)! As with many student design team projects, every component was hand built and designed to optimize the power to weight ratio of the vehicle.

The students from ETH Zurich and Lucerne University of Applied Sciences and Arts were excited to regain the record from the team at the University of Stuttgart, having previously held the title in 2014 and 2016. We suspect that they will find any European EV maker’s engineering department excited for the chance to hire them come graduation.

If you want to go fast at a smaller scale, checkout 3D printing RC car wheels for speed, and if you’d rather ride the rails at an accelerated rate, here’s an article on high speed rail.

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How Three Letters Brought Down UK Air Traffic Control

September 13, 2023 by 51 Comments

The UK bank holiday weekend at the end of August is a national holiday in which it sometimes seems the entire country ups sticks and makes for somewhere with a beach. This year though, many of them couldn’t, because the country’s NATS air traffic system went down and stranded many to grumble in the heat of a crowded terminal. At the time it was blamed on faulty flight data, but news now emerges that the data which brought down an entire country’s air traffic control may have not been faulty at all.

Armed with the official incident report and publicly available flight data, Internet sleuths theorize that the trouble was due to one particular flight: French Bee flight 731 from Los Angeles to Paris. The flight itself was unremarkable, but the data which sent the NATS computers into a tailspin came from two of its waypoints — Devil’s Lake Wisconsin and Deauville Normandy — having the same DVL identifier. Given the vast distance between the two points, the system believed it was looking at a faulty route, and refused to process it. A backup system automatically stepped in to try and reconcile the data, but it made the same determination as the primary software, so the whole system apparently ground to a halt.

It’s important to note that there was nothing wrong with the flight plan entered in by the French Bee pilots, and that early stories blaming faulty data were themselves at fault. However we are guessing that air traffic software developers worldwide are currently scrambling to check their code for this particular bug. We’re fortunate indeed that safety wasn’t compromised and only inconvenience was the major outcome.

Air traffic control doesn’t feature here too often, but we’ve previously looked at a much earlier system.

Header image: John Evans, CC BY-SA 2.0.

A silver and black bike sits in front of a dark grey bridge. It is on a hard surface next to green grass. The bike has a large basket area in front of the steering tube that then connects to the front wheel which is at the other end of the basket from the handlebars. It is best described as a long john bike, but is a more modern take on it than the wooden box Dutch bike.

Building A Cargo Bike Dream

September 12, 2023 by 54 Comments

Cargo bikes can haul an impressive amount of stuff and serve as a car replacement for many folks around the world. While there are more models every year from bike manufacturers, the siren song of a custom build has led [Phil Vandelay] to build his own dream cargo bike.

The latest in a number of experiments in hand-built cargo bike frames, this electrified front-loader is an impressive machine. With a dual suspension and frame-integrated cargo area, this bike can haul in style and comfort. It uses a cable steering system to circumvent the boat-like handling of steering arm long john bikes and includes a number of nice touches like (mostly) internal cable routing.

The video below the break mostly covers welding the frame with [Vandelay]’s drool-worthy frame jig, so be sure to watch Part 2 of the video for how he outfits the bike including the internal cable routing and turning some parts for the cable steering system on the lathe. If you get an urge to build your own cargo bike after following along, he offers plans of this and some of his other cargo bike designs. [Vandelay] says this particular bike is not for the beginner, unlike his previous version built with square tubing.

Looking for more DIY cargo bikes? Checkout this Frankenbike, another front loader, or this Russian trike.

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Your Car Is A Privacy Nightmare On Wheels

September 12, 2023 by 116 Comments

There was a time when a car was a machine, one which only came to life when its key was turned, and functioned simply as a way to get its occupants from point A to B. For most consumers that remains the case, but unfortunately in the last decade its function has changed from the point of view of a car manufacturer. Motor vehicles have become a software product as much as a hardware one, and your car now comes with all the privacy hazards you’d expect from a mobile phone or a computer. The Mozilla Foundation have taken a look at this problem, and their disturbing finding was that every one of the 25 major automotive brands they tested had significant failings.

Their quote that the cars can collect “deeply personal data such as sexual activity, immigration status, race, facial expressions, weight, health and genetic information, and where you drive.” had us wondering just exactly what kind of sensors they incorporate in today’s vehicles. But beyond mild amusement at some of the possibilities, it’s clear that a car manufacturer can glean a significant amount of information and has begun doing so largely without the awareness of the consumer.

We’ve railed about unnecessary over-computerisation of cars in the past, but from an obsolescence and reliability perspective rather than a privacy one, so it’s clear that the two issues are interconnected. There needs to be some level of public awareness that cars can do this to their owners, and while such things as this Mozilla investigation are great, the message needs to appear in more consumer-focused media.

As well as the summary, Mozilla also provide a detailed report broken down by carmaker.

Header: Michael Sheehan, CC BY 2.0.

New Electric Motor Tech Spins With No Magnets

September 10, 2023 by 58 Comments

When you think of electric motors, you usually think of magnets. But magnets are heavy, and good magnets can pose problems when you need lots of them. A technology called SESM (separately excited synchronous motors) requires no magnets, but now ZF — a German company — claims to have a different scheme using inductive excitation. Motors that employ SESM tend to be larger and require a direct current to turn the rotor. This DC is often supplied by slip rings or an AC induction with a rectifier. The innovation here is that the inductive excitation is built completely into the shaft, which the company claims makes the motor both compact and powerful.

This kind of motor is usually destined for electric vehicles. The company claims the motor reduces losses by about 15% over conventional techniques. To maximize efficiency, conventional SESM uses slip rings or brushes to transmit power to the shaft. However, ZF claims their inductive improvements are even more efficient and can reduce axial size by around 90 mm.

Another advantage of the technology is that there is no need to provide a dry space for slip rings. That means fewer seals and the ability to cool the rotor with oil as you would with a motor containing permanent magnets. The company plans to offer a 400 V version of the motor and an 800 V that uses silicon carbide electronics.

If you build your own motors, have you tried anything like this? Usually, we don’t see motors this big, of course. We have, however, seen builds of reluctance motors that don’t use magnets.

Teaching A Mini-Tesla To Steer Itself

September 2, 2023 by 4 Comments

At the risk of stating the obvious, even when you’ve got unlimited resources and access to the best engineering minds, self-driving cars are hard. Building a multi-ton guided missile that can handle the chaotic environment of rush-hour traffic without killing someone is a challenge, to say the least. So if you’re looking to get into the autonomous car game, perhaps it’s best to start small.

If [Austin Blake]’s fun-sized Tesla go-kart looks familiar, it’s probably because we covered the Teskart back when he whipped up this little demon of an EV from a Radio Flyer toy. Adding self-driving to the kart is a natural next step, so [Austin] set off on a journey into machine learning to make it happen. Having settled on behavioral cloning, which trains a model to replicate a behavior by showing it examples of the behavior, he built a bolt-on frame to hold a steering servo made from an electric wheelchair motor, some drive electronics, and a webcam attached to a laptop. Ten or so human-piloted laps around a walking path at a park resulted in a 48,000-image training set, along with the steering wheel angle at each point.

The first go-around wasn’t so great, with the Teskart seemingly bent on going off the track. [Austin] retooled by adding two more webcams, to get a little parallax data and hopefully improve the training data. After a bug fix, the improved model really seemed to do the trick, with the Teskart pretty much keeping in its lane around the track, no matter how fast [Austin] pushed it. Check out the video below to see the Teskart in action.

It’s important to note that this isn’t even close to “Full Self-Driving.” The only thing being controlled is the steering angle; [Austin] is controlling the throttle himself and generally acting as the safety driver should the car veer off course, which it tends to do at one particular junction. But it’s a great first step, and we’re looking forward to further development.

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