Solar Boat Makes Waves

August 11, 2023 by Bryan Cockfield 11 Comments

The two best days in a boat owner’s life are the day they buy it, and the day they sell it. At least, that’s the common saying among people who actually spend money to buy a boat. [saveitforparts], on the other hand, looks like he’s going to have many more great days on this boat than that since he cobbled it together nearly for free, and he won’t even need to purchase any fuel for it since it runs on solar power.

The build starts with [saveitforparts] heading out to a literal pile of boats in his yard, unearthing an old single-person sailboat, and then fixing the major problems with its hull. With a new coat of red paint, the focus turns to the drivetrain. Propulsion is handled by an electric trolling motor found at an auction for $8 and is powered by an off-the-shelf battery bank provided by a sponsor of his channel. A pair of solar panels (which were traded for) fitted to outriggers keep the battery bank topped off, and there’s plenty of energy left over with this setup to charge drone batteries and other electronics while out on the lake.

[saveitforparts] reports that the single-passenger solar boat is remarkably stable on the water and fairly quick at full speed thanks to its light weight. He even hypothesizes that it could be fished from. The only thing not particularly stable was towing it to the lake, as the rough roads and permanently-attached solar panel outriggers weren’t particularly congruent with each other. If you’re looking for something similar to carry a few passengers, though, have a look at this much larger version.

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Pedal Car Vs Ministry Of Transport

August 9, 2023 by Jonathan Bennett 48 Comments

[Tim] from the “Way Out West” Youtube channels has started a fun project — building a wooden pedal-car heavily inspired by “Bugsy Malone”. The kids-sized gangsters in that movie got around in kid-sized pedal cars. Apparently kid-sized [Tim] just loved the idea, but just didn’t have the skills or tools to try to build one. But the time has come, and he has spent years putting together a workshop, tools, and skills.

The goal is a 4-wheeled vehicle that can actually be enclosed, to keep the driver out of the rain. It would be petal powered, with an optional electric assist. It should be made of simple materials, like plywood and epoxy. The design would be freely shared, and the overall cost hopefully kept low. Come back after the link to find the rest of the story, including the monkey wrench thrown into the works.
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A Magnetohydrodynamic Drive In The Kitchen Sink

August 7, 2023 by Tom Nardi 58 Comments

The magnetohydrodynamic (MHD) drive certainly sounds like something out of science fiction — using an array of magnets and electrodes, this high-tech propulsion technology promises to silently propel a craft through the water without any moving parts. As long as you can provide it with a constant supply of electricity, anyway.

Of course, as is often the case, the devil is in the details. Even with the obvious scientific and military applications of such a propulsion unit, scaling MHD technology up has proven difficult. But as [Jay Bowles] of Plasma Channel shows in his latest video, that doesn’t mean you can’t experiment with the concept at home. Even better, getting verifiable results is much easier than you’d think.

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The State Of High Speed Rail, And A Look To Tomorrow

August 3, 2023 by Lewin Day 73 Comments

In the 21st century, the global transportation landscape is in shift. Politicians, engineers, and planners all want to move more people, more quickly, more cleanly. Amid the frenzy of innovative harebrained ideas, high-speed rail travel has surged to the forefront. It’s a quiet achiever, and a reliable solution for efficient, sustainable, and swift intercity and intercountry transit.

From the thriving economies of Europe and Asia to the burgeoning markets of the Middle East and America, high-speed rail networks are being planned, expanded, and upgraded whichever way you look. A combination of traditional and magnetic levitation (maglev) trains are being utilized, reaching speeds that were once the stuff of science fiction. As we set our sights towards the future, it’s worth taking a snapshot of the current state of high-speed rail, a field where technology, engineering brilliance, and visions of a greener tomorrow converge.

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Truss-Braced Wings Could Bring New Look To Runways Worldwide

August 2, 2023 by Lewin Day 75 Comments

Airliners have looked largely the same for a long time now. The ongoing hunt for efficiency gains has seen the development of winglets, drag reducing films, and all manner of little aerodynamic tricks to save fuel, and hence money.

Boeing now has its eye on bigger, tastier goals. It believes by switching to a truss-braced wing design, it could net double-digit efficiency gains. It’s working together with NASA to see if this concept could change the face of commercial aviation in decades to come.

Aspect Ratio Matters

The ASH 31 glider features wings with an aspect ratio of 33.5, and a lift-to-drag ratio of 56. *Credit: Manfred Munch, CC-BY-SA 3.0*

The key goal of using a truss-braced wing is to enable an airliner to use a wing much thinner and narrower than usual. These “high aspect ratio” wings are far more efficient than the stubbier, wider wings currently common on modern airliners. But why is aspect ratio so important, and how does it help

If you’ve ever looked at a glider, you will have noticed its incredibly long and narrow wings, which stand it apart from the shorter, wider wings used on airliners and conventional small aircraft. These wings are said to have a high aspect ratio, the ratio between the square of the wingspan and the projected area of the wing itself.

These wings are highly desirable for certain types of aircraft, as lift-to-drag ratio increases with aspect ratio. Any wing that generates lift also generates some drag, but this can be minimized through careful wing design. By making the wings longer and narrower, and thus higher in aspect ratio, the wing tip vortices generated by the wing are weakened. This reduces drag on the plane, and quite significantly so. Continue reading “Truss-Braced Wings Could Bring New Look To Runways Worldwide” →

Car Security System Monitors Tiny Voltage Fluctuations

July 25, 2023 by Bryan Cockfield 43 Comments

As the old saying goes, there’s no such thing as a lock that can’t be picked. However, it seems like there are plenty of examples of car manufacturers that refuse to add these metaphorical locks to their cars at all — especially when it comes to securing the electronic systems of vehicles. Plenty of modern cars are essentially begging to be attacked as a result of such poor practices as unencrypted CAN busses and easily spoofed wireless keyfobs. But even if your car comes from a manufacturer that takes basic security precautions, you still might want to check out this project from the University of Michigan that is attempting to add another layer of security to cars.

The security system works like many others, by waiting for the user to input a code. The main innovation here is that the code is actually a series of voltage fluctuations that are caused by doing things like turning on the headlights or activating the windshield wipers. This is actually the secondary input method, though; there is also a control pad that can mimic these voltage fluctuations as well without having to perform obvious inputs to the vehicle’s electrical system. But, if the control pad isn’t available then turning on switches and lights to input the code is still available for the driver. The control unit for this device is hidden away, and disables things like the starter motor until it sees these voltage fluctuations.

One of the major selling points for a system like this is the fact that it doesn’t require anything more complicated than access to the vehicle’s 12 volt electrical system to function. While there are some flaws with the design, it’s an innovative approach to car security that, when paired with a common-sense approach to securing modern car technology, could add some valuable peace-of-mind to vehicle ownership in areas prone to car theft. It could even alleviate the problem of cars being stolen via their headlights.

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VanMoof E-Bike Bankruptcy: The Risks Of Cloud-Connected Transport

July 23, 2023 by Maya Posch 66 Comments

When the bankruptcy of VanMoof, the company behind a series of e-bikes, was announced recently, many probably shrugged at this news. After all, what is an e-bike but a regular bicycle that has some electronics and a battery strapped to it to assist with cycling? Unfortunately for owners of a VanMoof e-bike, their fancy wheels come with a Bluetooth-connected smartphone app that somehow involves storing a special encryption key on the VanMoof servers, as detailed by [Gergely Orosz] at the Pragmatic Engineer. Without this key that is connected to your VanMoof account, your VanMoof app cannot communicate with your VanMoof e-bike.

Although basic functionality of the e-bike will be retained, features such as setting the gear modes, changing assistance mode, locking the bicycle and other features not exposed on the bicycle itself will be lost. Essentially this is the equivalent of losing the remote control to a modern-day TV and getting locked out of 90% of the device’s features.

Fortunately, as [Gergely] and others are (urgently) pointing out to VanMoof e-bike owners, this special key can be downloaded with a Key Exporter project on GitHub, as well as obtained and used with an alternative app by Cowboy Bikes, which is a competitor of VanMoof. The unfortunate reality remains, however, that should you lose this special key, you are going to be in a world of pain as your expensive e-bike now is mostly an e-brick.

(Thanks to [Jan Praegert] for the tip)