PLA Gears Fail To Fail In 3D Printed Bicycle Drivetrain

October 10, 2025 by Tyler August 33 Comments

Anyone who has ever snapped a chain or a crank knows how much torque a bicycle’s power train has to absorb on a daily basis; it’s really more than one might naively expect. For that reason, [Well Done Tips]’s idea of 3D printing a gear chain from PLA did not seem like the most promising of hacks to us.

Contrary to expectations, though, it actually worked; at the end of the video (at about 13:25), he’s on camera going 20 km/h, which while not speedy, is faster than we thought the fixed gearing would hold up. The gears themselves, as you can see, are simple spurs, and were modeled in Fusion360 using a handy auto-magical gear tool. The idler gears are held in place by a steel bar he welded to the frame, and are rolling on good old-fashioned skateboard bearings–two each. (Steel ones, not 3D printed bearings.) The healthy width of the spur gears probably goes a long way to explaining how this contraption is able to survive the test ride.

The drive gear at the wheel is steel-reinforced by part of the donor bike’s cassette, as [Well Done Tips] recognized that the shallow splines on the freewheel hub were not exactly an ideal fit for PLA. He does complain of a squeaking noise during the test ride, and we can’t help but wonder if switching to helical gears might help with that. That or perhaps a bit of lubricant, as he’s currently riding the gears dry. (Given that he, too, expected them to break the moment his foot hit the pedal, we can’t hardly blame him not wanting to bother with grease.)

We’ve seen studies suggesting PLA might not be the best choice of plastic for this application; if this wasn’t just a fun hack for a YouTube video, we’d expect nylon would be his best bet. Even then, it’d still be a hack, not a reliable form of transportation. Good thing this isn’t reliable-transportation-a-day!

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Building A Diwheel To Add More Tank Controls To Your Commute

October 7, 2025 by Maya Posch 19 Comments

It’s often said that one should not reinvent the wheel, but that doesn’t mean that you cannot change how the use of said wheel should be interpreted. After initially taking the rather zany concept of a monowheel for a literal ride, [Sam Barker] decided to shift gears, did a ‘what if’ and slapped a second monowheel next to the first one to create his diwheel vehicle. Using much thicker steel for the wheels and overall much more robust construction than for his monowheel, the welding could commence.

It should be said here that the concept of a diwheel, or dicycle, isn’t entirely new, but the monowheel – distinct from a unicycle – is much older, with known builds at least as far back as the 19th century. Confusing, self-balancing platforms like Segways are also referred to as ‘dicycles’, while a diwheel seems to refer specifically to what [Sam] built here. That said, diwheels are naturally stable even without gyroscopic action, which is definitely a big advantage.

The inner frame for [Sam]’s diwheel is built out of steel too, making it both very robust and very heavy. High-tech features include suspension for that smooth ride, and SLS 3D-printed nylon rollers between the inner frame and the wheels. After some mucking about with a DIY ‘lathe’ to work around some measurement errors, a lot more welding and some questionable assembly practices, everything came together in the end.

This is just phase one, however, as [Sam] will not be installing pedals like it’s an old-school monowheel. Instead it’ll have electrical drive, which should make it a bit less terrifying than the Ford Ka-based diwheel we featured in 2018, but rather close to the electric diwheel called EDWARD which we featured back in 2011. We hope to see part two of this build soon, in which [Sam] will hopefully take this beast for its first ride.

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The WindRunner unloading a blade, image Radia.

Giant Airplane Goes Long On Specialization

October 3, 2025 by Tyler August 63 Comments

While not everyone agrees on the installation of wind turbines in their proverbial back yards, one thing not up for debate is that there is a drive to build them bigger, and bigger. Big turbines means big blades, and big blades need to be transported… somehow. If air freight is going to stay relevant to the industry, we’re gonna need a bigger airplane.

A startup called Radia has a plan for that plane, and it is a doosie. The “WindRunner” would clock in at a massive 108 meters (354 feet) long, but with a wingspan of just 80 m (262 ft). That’s very, very long, but it might not be the largest airplane, depending how you measure it. Comparing to the 88 m wingspan for the late, lamented An-225 Mriya, you can expect a lower payload capacity, but heavy payloads aren’t the point here. Wind turbine blades really aren’t that heavy. They’re big, or they can be — the WindRunner is designed to fit a single 105 m blade within its long fuselage, or a pair of 90 m blades.

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A forest green kei truck sits in an actual forest. In its bed is a dark grey box with a small window, wood trim, and a solar panel tilted on its roof. The headlights are on, hinting at the onset of twilight. You have a sudden urge to go glamping now.

Kei Truck Becomes Tiny RV

October 2, 2025 by Navarre Bartz 16 Comments

Tent camping lets you explore places on foot you could never reach another way, but sometimes you want to camp with a bit more luxury. [Levi Kelly] decided to see how small you could make an RV. [via Autopian]

While we won’t argue one way or another on his claim to world’s smallest, as that likely depends on your definition of an RV, starting with a kei truck certainly puts you in a more compact format than something built on a bus chassis. With four wheel drive and a small footprint, this could be better for overlanding than the Rivian bed camper we featured recently.

The 21 sq. ft. (1.95 m²) camper portion itself is framed in 2 x 2s (38 x 38 mm) to save weight and uses foam board insulation. A working faucet uses a pump to draw drinking water from a 5 gallon (19L) refillable jug and empties into a 7 gallon (26L) grey water tank. A solar panel on the roof charges the battery that drives the pump, ventilation fan, and can also be used to run other devices like a hot plate for cooking.

A teeny tiny wood stove can be used for heat, although [Kelly] is using a different fuel source to reduce unpredictability from a wood fire in such a small space. A faucet-mounted sprayer can be routed to the outside of the camper to create a makeshift shower and is run from the sink water system. There’s even a small cabinet above the foot area of the bed to house a portable toilet and a bubble window to observe your surroundings while you do your business.

We’ve seen some even smaller campers, like this vintage-inspired bike camper, or this more streamlined version. If you want the most efficient RV ever then check out this solar-powered one.

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A suitcase made of two rectangular plastic crates latched together sits prone on a concrete floor. The top shell is a beige-ish grey with a navy check and the word "JerseyMaid" on it updside down. The navy bottom crate is navy with the letters "lsen" in large cursive font ant the letters "ORATION" in smaller print below it. Much of the text is covered by a large latch and a power tool battery mount. Bright pink tape affixes a blue tarp skirt to the bottom of the hover suitcase.

Hovercraft Suitcase Gives Your Luggage A Smooth Ride

September 25, 2025 by Navarre Bartz 8 Comments

The wheels on roller suitcases are one of their primary failure points. After the destruction of the wheel mount on her DIY suitcase, [Laura Kampf] wondered if it would be better to dispense with wheels altogether.

To give her suitcase a lift, [Kampf] decided to turn it into a hovercraft so it couldn’t be stopped by pavement or puddles. The first task was finding an appropriate fan, and a compact leaf blower donated it’s body to makerdom for the project. After reducing the blower to it’s constituent components and finding a secret turbo switch, work began on the momentum curtain.

“Nose-holing” the arrangement and size of the holes to pipe air through the stapled tarp and tape skirt seemed to be the bulk of the trial-and-error in this one. Based on other hovercraft designs [Kampf] found, keeping the holes near the center of the inflated portion gave better lift. In the end, the carry-on is able to lift a decent amount even on its lowest setting, resulting in a suitcase that is “not embarrassing” for travel. No word yet on what TSA thinks.

If you’re looking for another unexpected lift off, how about a full-sized flying Delorean replica? We’ve also covered some of the reasons why we don’t see more of these all terrain wonders.

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Solar-Powered RC Boat Has Unlimited Range

September 25, 2025 by Bryan Cockfield 5 Comments

For RC aircraft there are generally legal restrictions that require the craft to stay within line of sight of the operator, but an RC boat or car can in theory go as far as the signal will allow — provided there is ample telemetry to let the operator navigate. [Thingify] took this idea to the extreme with a remote-controlled boat that connects to a satellite internet service and adds solar panels for theoretically unlimited range, in more ways than one.

The platform for this boat is a small catamaran, originally outfitted with an electric powertrain running on a battery. Using a satellite internet connection not only allows [Thingify] to receive telemetry and pilot the craft with effectively unlimited range, but it’s a good enough signal to receive live video from one of a pair of cameras as well. At that point, the main limiting factor of the boat was the battery, so he added a pair of flexible panels on a custom aluminum frame paired with a maximum power point tracking charge controller to make sure the battery is topped off. He also configured it to use as much power as the panels bring in, keeping the battery fully charged and ready for nightfall where the boat will only maintain its position and wait for the sun to rise the next morning.

With this setup [Thingify] hopes to eventually circumnavigate Lake Alexandrina in Australia. Although he has a few boat design issues to work out first; on its maiden voyage the boat capsized due to its high center of gravity and sail-like solar panels. Still, it’s an improvement from the earlier version of the craft we saw at the beginning of the year, and we look forward to his next iteration and the successful voyage around this lake.

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Retrotechtacular: The Ferguson System

September 24, 2025 by Jenny List 37 Comments

Of the many great technological leaps made in the middle of the 20th century, one of the ones with perhaps the greatest impact on our modern life takes a back seat behind the more glamorous worlds of electronics, aeronautics, or computing. But the ancestor of the modern tractor has arguably had more of an impact on the human condition in 2025 than that of the modern computer, and if you’d been down on the farm in the 1940s you might have seen one.

The Ferguson system refers to the three-point implement linkage you’ll find on all modern tractors, the brainchild of the Irish engineer Harry Ferguson. The film below the break is a marketing production for American farmers, and it features the Ford-built American version of the tractor known to Brits and Europeans as the Ferguson TE20.

The evolution of the tractor started as a mechanisation of horse-drawn agriculture, using either horse-drawn implements or ones derived from them. While the basic shape of a modern tractor as a four wheel machine with large driving wheels at the rear evolved during this period, other types of tractor could be found such as rein-operated machines intended to directly replace the horse, or two-wheeled machines with their own ecosystem of attachments.

As the four-wheeled machines grew in size and their implements moved beyond the size of their horse-drawn originals, they started to encounter a new set of problems which the film below demonstrates in detail. In short, a plough simply dragged by a tractor exerts a turning force on the machine, giving the front a tendency to lift and the rear a lack of traction. The farmers of the 1920s and 1930s attempted to counter this by loading their tractors with extra weights, at the expense of encumbering them and compromising their usefulness. Ferguson solved this problem by rigidly attaching the plough to the tractor through his three-point linkage while still allowing for flexibility in its height. The film demonstrates this in great detail, showing the hydraulic control and the feedback provided through a valve connected to the centre linkage spring. Continue reading “Retrotechtacular: The Ferguson System” →