Rubber Band Behemoth Winds Its Way Toward World Record

October 6, 2022 by Ryan Flowers 25 Comments

Egged on by adoring fans who demanded more aircraft videos, [ProjectAir] has decided to break the world record for rubber band powered aircraft… despite having never built a rubber band powered aircraft. Why rubber band power?

Before little two stroke motors became affordable, and long before electric motors and batteries were remotely possible, there weren’t a lot of options for powering your model aircraft. One technology that really took off was that of rubber band power. By winding a rubber band, it could store enough energy to turn a propeller for a short duration. With a 10 foot model taking the current world record, as you can see in the video below the break [ProjectAir] decided to see if he could beat it.

Rubber Band Powered Free Flight c1915 By Unknown author –

Starting with a successful free flight aircraft made of foam board, [ProjectAir] simply scaled it up to an eleven foot wing- one foot larger than the ten foot world record holder. Since there were now eight rubber band motors, a mechanism was created to release the propellers in sync, but this was problematic. Eventually a slightly heavy but solid solution was found.

[ProjectAir] did more testing, more problem solving, and through rapid iterations, he eventually was able to have a successful flight under radio control. His personal goal of a 12 second flight was exceeded, and then Guinness called! They’re interested in certifying his attempt as long as his plane can fly for at least 30 seconds- almost double his current ability. What will he do? Check the video, too, for [ProjectAir]’s challenge to the community to join him in trying to beat the world record. Sounds like fun!

Aside from powering world record attempting radio controlled aircraft, did you know that you can build a rubber band powered refrigerator? It’s true!

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Adding A Third Wheel (And Speed Boost) To An Electric Scooter

September 24, 2022 by Donald Papp 7 Comments

The story of how [Tony]’s three-wheeled electric scooter came to be has a beginning that may sound familiar. One day, he was browsing overseas resellers and came across a new part, followed immediately by a visit from the Good Ideas Fairy. That’s what led him to upgrade his DIY electric scooter to three wheels last year, giving it a nice speed boost in the process!

The part [Tony] ran across was a dual brushless drive unit for motorizing a mountain board. Mountain boards are a type of off-road skateboard, and this unit provided two powered wheels in a single handy package. [Tony] ended up removing the rear wheel from his electric scooter and replacing it with the powered mountain board assembly.

He also made his own Arduino-based interface to the controller that provides separate throttle and braking inputs, because the traditional twist-throttle of a scooter wasn’t really keeping up with what the new (and more powerful) scooter could do. After wiring everything up with a battery, the three-wheeled electric scooter was born. It’s even got headlights!

[Tony]’s no stranger to making his own electric scooters, and the fact that parts are easily available puts this kind of vehicular experimentation into nearly anybody’s hands. So if you’re finding yourself inspired, why not order some stuff, bolt that stuff together, and go for a ride where the only limitation is personal courage?

Wow! You Could Have A (Tiny) V8!

September 21, 2022 by Al Williams 30 Comments

If you grew up before high gas prices and strict emission control regulations, you probably had — or wanted — a car with a V8 engine. An engineering masterpiece created in France, it would define automotive power for the best part of a century. Of course, you can still get them, but the realities of our day make them a luxury. [Vlad] shows us his latest Christmas list addition: a fully-functioning but tiny V8 — the Toyan FS-V800 that has a displacement of two centiliters.

It runs on R/C nitro fuel and is claimed to be the world’s smallest production V8. You can buy the thing built or as a kit and we suggest to protect your street cred, you claim you bought the kit even if you go for the assembled version. The cylinder bores are 17 mm and 16 tiny valves regulate the flow. There are even tiny mufflers for the manifold exhaust. [Dennis] has a video of his operating that you can see below, and his YouTube channel has a lot of information on building the kit and some modifications, too.

Cooling? Water-cooled, of course. The manufacturer claims the engine can rev to 12,500 RPM and can produce over four horsepower. The total size would allow it to fit easily in a five inch cubical volume. You could build it into something, or just display it as a conversation piece. Be prepared for sticker shock, though. We hear the going price for these is about $1,500.

If you’re a bit short on cash or would rather just play with some pretend ponies, this impressive open source engine simulator might be just what you’re looking for.

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Finally We Can Watch The Deere Cracking Def Con Talk

September 12, 2022 by Jenny List 12 Comments

A few weeks ago, some tantalizing social media posts emerged from a Def Con talk, in which [Sick Codes] broke into the screen control unit for a John Deere tractor live on stage, and proceeded to play a special Deere-themed DOOM level upon it. At the time there was nothing more to go on, but we’re pleased to find out that the whole talk has been put online.

The talk starts with an introduction to the topic, to the basics of the control units within the machine and to the various different ages of Deere screen unit. We find that the earlier machines, which are still at work on farms worldwide, rely on outdated Windows CE versions, though the very latest screens run a Linux variant.

It’s one of these last screens to which he turns his attention, and we’re treated to an in-depth look at some of its secrets. After a lot of dead ends and learning exercises the final result is distilled into a pogo pin adapter for the hardware part, and a simple enough cron job to bypass one of Deere’s defenses by keeping the filesystem writable so a file can be updated. There’s a bit more detail about the special DOOM level too, as a special bonus.

You can see our original mention of this talk, or read some of our past Deere coverage.

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Motorcycle Builder Makes Downhill Mountain Bike

September 9, 2022 by Bryan Cockfield 17 Comments

[Allen Millyard] is a premier British motorcycle builder. In these circles he is widely regarded and his custom motorcycles are nearly world-famous. But when his son took up downhill mountain biking, he decided to put his skills building a different type of vehicle. This is the Millyard MR001, one of the most unique mountain bikes ever built thanks to some design choices that solve many problems otherwise inherent in bicycles.

Perhaps the most immediately striking design of this bike is the aluminum space frame, a lightweight but extremely strong frame necessary for the high speeds and stresses of downhill mountain biking. Upon closer inspection, however, the sealed drivetrain warrants further inspection. Unlike most mountain bikes with gears, this one eliminates the typical derailleur which hangs below the rear gears. The gears are instead above the pedals in front of the rear tire, are completely sealed eliminating the maintenance requirements of a typical bike, and are designed in such a way that they can be shifted without the bike moving.

Despite the bike being built in 2007, it still includes plenty of features that still aren’t widely adopted in mountain biking. It’s also nearly completely silent thanks to the custom drivetrain, and [Allen] reports that it still sneaks up on other mountain bikers as a result. This is essentially the opposite problem of another bike we’ve seen around.

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Electric Surfboard Gets An Overhaul

September 6, 2022 by Matthew Carlson 5 Comments

One of the realities of building your own hardware is that it will more often than not lead to constant tinkering and revisions. [Simon]’s 3D printed electric surfboard is no exception as it recently got an overhaul. The motors were upgraded from 5000 W to 7500 W, most parts were redesigned to use bearings, and the impellers were swapped out. Luckily, almost all the electronics inside were suitable for reuse.

We previously covered the surfboard in question, and we’re always excited to see an old project revisited. The bearing reduces vibrations and allows the system to last longer. Despite the water cooling on the motors, the temperatures were still getting relatively high when running full tilt. So rather than buying more efficient (and more expensive) motors, he opted to reduce the load on the motors by changing out the impeller from a double to a single. But this meant cutting and grinding a new shaft as now needed to be one impeller shorter.

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Small Engine Failure Leads To Impromptu Teardown

September 1, 2022 by Tom Nardi 20 Comments

When the 6.5 HP (212 cc) Harbor Freight Predator engine in his kid’s go-kart gave up the ghost after some particularly hard driving, [HowToLou] figured it would be a good time to poke around inside the low-cost powerplant for our viewing pleasure. As a bonus, he even got it up and running again.

For an engine that has a retail price of just $160 USD, we’ve got to admit, the inside of the Predator doesn’t look too shabby. Admittedly, [HowToLou] determined that the cause of the failure was a blown connecting rod, but he also mentions that somebody had previously removed the engine’s governor, allowing it to rev up far beyond the nominal maximum of 3,600 RPM. No word on who snuck in there and yanked the governor out, but we’re betting it wasn’t the 7-year old driver…

Replacing the connecting rod meant taking most of the engine apart, but for our education, [HowToLou] decided to take it a bit further and remove everything from the engine. After stripping it down to the block, he re-installs each piece while explaining its function. If you’ve ever wanted to see what makes one of these little engines tick, or perhaps you’ve got a Predator 212 cc in need of a repair or rebuild, the presentation is a fantastic resource.

Incidentally, this isn’t the first time we’ve seen the go-kart in question — back in June, we covered the unique electric reverse that [HowToLou] came up with for it.