EBike Conversion On A Budget Uses Skateboard Motor

August 28, 2021 by Mike Szczys 30 Comments

[Dave Schneider] has been chasing an electric-bike build for more than 10 years now. When he first started looking into it back in 2009, the cost was prohibitive. But think of how far we’ve come with the availability of motors, electronic speed controllers, and of course battery technology. When revisiting the project this year, he was able to convert a traditional bicycle to electric-drive for around $200.

Outrunner motor drives rear wheel via friction

Electric skateboards paved the way for this hack, as it was an outrunner motor that he chose to use as a friction drive for the rear wheel. The mounting brackets he fabricated clamp onto the chain stay tubes and press the body of the motor against the tire.

The speed of the motor is controlled by a rocker switch on the handlebars, but it’s the sensors in the brake levers that are the neat part. Magnets added to each brake lever are monitored by hall-effect sensors so that the throttle cuts whenever it senses the rider squeezing the front brake (effectively free-wheeling the bike), while the rear brake triggers a regenerative braking function he’s built into the system!

Sure you can buy these bikes, you can even buy conversion kits, but it’s pretty hard to beat the $88 [Dave] spent on the motor when the cost of purpose-built motors is usually several times this figure. The rest is fairly straight-forward, and besides ordering batteries and an electronic speed controller, you likely have the bits you need just waiting for you in your parts bin.

Wooden Monowheel Build Is Simplicity Itself

August 23, 2021 by Dave Rowntree 9 Comments

Monowheels are nothing new, first being patented in the middle of the 19th century, but never really went mainstream due to, well, quite a lot of obvious issues. We’ve got problems with forward visibility, stability, steering, especially at speed, and the hilariously-named ‘gerbiling’ where the rider can spin around inside the wheel akin to a gerbil in a wheel. Fun times! But obviously that didn’t stop [The Q] from adding to the monowheel corpus by building one out of wood.

Sometimes people take on these projects simply for a laugh, like this bright orange one we covered a while back. Sometimes they’re powered by a motor, be it electric or internal combustion. Some are hand-cranked, some are pedal-powered, its all been tried.

[The Q] is no stranger to interesting wooden builds, and this video from a year ago shows him building a very simple direct-pedal-drive monowheel. The vast majority of the structure is wood, glued and screwed the old-fashioned way, with a bit of metalwork where necessary. We particularly like the simple counterweight solution which doubles up as a parking brake. It may look a little ungainly, but we can’t think of a simpler solution that would make much sense.

The build video after the break is six and half minutes of well executed videography for your viewing pleasure.

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Retrotechtacular: LA’s Hilarious Subway Safety Film From 1992

August 13, 2021 by Lewin Day 17 Comments

Subways! They’ve been around for an awfully long time; almost as long as modern railways themselves, believe it or not. Building underground was undertaken in earnest by those in the 19th century, who set out to build networks of stations to allow residents to get around a city quickly and effectively.

That fact should stick in your mind as you sample this glorious retro video from 1992. “L.A. Underground – Safety in the Extreme” is a guide for Californians, aiming to educate residents about the new B Line subway that opened the following year. The video acts as if the subway is a new fangled, mysterious thing, with a couple of confusing off-the-wall moments as well. If you’re a transport enthusiast or get excited about weird public films, this one’s for you.

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China MagLev Train Aspirations Boosted By New 600 Km/h Design

August 10, 2021 by Lewin Day 65 Comments

Maglev trains have long been touted as the new dawn for train technology. Despite keen and eager interest in the mid-20th century, development has been slow, and only limited commercial operations have ever seen service. One of the most well-known examples is the Shanghai Maglev Train which connects the airport to the greater city area. The system was purchased as a turnkey installation from Germany, operates over a distance of just 30.5 km, and according to Civil Engineering magazine cost $1.2 billion to build in 2001. Ever since, it’s served as a shining example of maglev technology — and a reminder of difficult and expensive maglev can be.

However, China has fallen in love with high-speed rail transport in the last few decades and has invested heavily. With an aggressive regime of pursuing technology transfers from foreign firms while building out the world’s largest high-speed rail network, the country has made great progress. Now, Chinese rail transit manufacturer, CRRC Corporation, have demonstrated their newest maglev train, which hopes to be the fastest in the world.

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From Tube And Wing To Just Wing: The Future Of Airliners

August 8, 2021 by Danie Conradie 77 Comments

Airliners have become an unremarkable part of modern life, but unless you happen to be an aircraft enthusiast, you’d be forgiven for thinking the latest Airbus model looks more or less the same as the Boeing 707 that ushered in the Jet Age. But that might soon change, with blended wing airliners looking like the next step in air travel efficiency. In the video after the break, [Real Engineering] takes us on a fascinating tour of the past and possible future of jet airliners.

Contemporary airliners all still follow the same old “tube and wing” design, but have become vastly more efficient. The latest jetliners burn almost 50% less fuel per passenger-km than they did 50 years ago. This is thanks to better engines, improved aerodynamics, reduced weight, and a vast array of other, often invisible changes. However, it’s looking like a more drastic change is needed to keep the progress going, and NASA, Boeing, and Airbus are all betting on blended wing designs to do this.

Blended wing aircraft are basically flying wings, where the cargo-carrying section of aircraft is shorter, wider, and produces lift. This layout can be used to increase the aircraft’s internal volume, and improve aerodynamic losses, by eliminating the tail. Research shows that blended wing design could reduce fuel consumption by as much as 27%. Since load and produced lift are spread more evenly along the entire width of the aircraft, it also reduces the amount of structural reinforcement required for the wings, especially at the root. The large internal volumes also allow other power sources, like hydrogen fuel cells to be used.

Blended wing aircraft are not without challenges. They are inherently unstable and require complex control systems to fly. These control systems depend on sensors, actuators, and software to work properly, and require multiple levels of redundancy. The omission of these redundancies ultimately led to the 2008 crash of a B-2 bomber, and the more recent fatal crashes of Boeing’s 737 MAX airliners. Also, unlike tubular fuselages, blended wing designs are not ideal pressure vessels. However, this is not a major problem thanks to the availability of carbon composite materials to create strong, lightweight structures.

With aircraft technology moving as fast as ever, we look forward to seeing what the future will bring. Whether it’s personal rotorcraft or commercial space flight, it sure won’t be boring.

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Single-Wheel Motorcycle Trailer

August 2, 2021 by Danie Conradie 40 Comments

A motorbike might not take up a lot of parking space, but this is not true for the trailer required to transport one. To solve this problem, [Make It Extreme] built a custom single-wheel motorbike trailer barely wider than the motorcycle itself.

The frame of the trailer is welded together from a couple of sections of large diameter steel tube, with a single car wheel mounted to a C-shaped portion on the rear end. A standard ball hitch would allow the entire trailer to tilt over to one side, so a pin hitch is used instead, with a pivot to allow up and down movement. Another pivot was added to the frame just ahead of the rear wheel to allow the trailer to lower to the ground for loading. It is raised and lowered with a manually pumped hydraulic cylinder, and a small pivoting ramp at the back also acts as a stop for the motorbike’s rear wheel. With the rigid frame and no suspension, we’re just wondering how well it will handle bumps at high speed.

[Make It Extreme] really likes his recreational vehicles, which include a monotrack motorbike, a monowheel, and an all-terrain hoverboard, among others. Continue reading “Single-Wheel Motorcycle Trailer” →

British Big Rigs Are About To Go Green

July 31, 2021 by Jenny List 78 Comments

An increasing fact of life over the coming years will be the decarbonisation of our transport networks, for which a variety of competing solutions are being touted. Railways, trucks, cars, and planes will all be affected by this move away from fossil fuels, and while sectors such as passenger cars are making great strides towards electric drive, there remain some technical hurdles elsewhere such as with heavy road freight. To help inform the future of road transport policy in the UK then, the British government are financing a series of trials for transportation modes that don’t use internal combustion. These will include a battery-electric fleet for the National Health Service and a hydrogen-powered fleet in Scotland, as well as a trial of the same overhead-wire system previously given an outing in Germany, that will result in the electrification of a 12.4 mile section of the M180 motorway in Lincolnshire.

We’ve written about the overhead electrification project in Germany in the past and subjected it to a back-of-envelope calculation that suggested the total costs for a country such as the UK might be surprisingly affordable. The M180 is something of a backwater in the UK motorway network though, so it will be interesting to see how they approach the problem of finding real-world loads for their tests that ply such a short and isolated route. We’d expect the final picture to include all three technologies in some form, which can only be a good thing if it increases the available electric and hydrogen infrastructure. We’ll follow this story, though sadly we may not be able to blag a cab ride on the M180 in one of the trucks.