3D Printed Spuds Are Begging To Be Fired

The ballistics of humble potato is a time-honoured research topic for everyone who likes things that go bang. The focus of such work is usually on the launcher itself, with the projectiles being little more than an afterthought. [drenehtsral] decided that the wares of the local organic ammunition supplier were not good enough for him and his minions, so he designed and then 3D printed some rifled potato cannon slugs.

The design was done using OpenSCAD, has a number of adjustable parameters like infill and rifling. We doubt that the rifling introduces any spin, since it is being fired from a smooth bore barrel, but as always 3D printing brings the capability to quickly test different ideas. A quick search on Thingiverse shows a number of 3D printed spuds, so [drenehtsral] is not the first give it a go. However, this did bring to our attention that the field of spud gun projectiles is begging to be explored.

There is enough space inside a projectile to fit an IMU and logging electronics, which would give some very nice empirical data (providing you can recover it of course) on spin, acceleration, and trajectory that can be used to further improve designs. Spring loaded stabilising fins would be cool, and maybe someone can even manage to implement some form of guidance? The possibilities are endless! If you’re up for the challenge, please document your work it and let us know.

As you would expect we have no shortage of potato cannon themed content, ranging from cartridge firing and bolt action versions to antenna launchers and Arduino-powered fire control systems.

Monster Bush Plane Is A One-Off Engineering Masterpiece

All of us dream of reaching a point in life where we have the knowledge, skills, energy and resources to pull off builds that match our wildest dreams. [Mike Patey] is living that dream and with a passion for engineering and aviation that is absolutely infectious, he built Draco, the world’s most badass bush plane.

Draco started life as a PZL-104MA Wilga 2000, which already had impressive short take off and landing (STOL) capabilities for a 4 seater. Its original 300 hp Lycoming piston engine failed catastrophically in 2017, very nearly dumping [Mike] in Lake Utah. He decided it was a good excuse to start building his dream plane, and replaced the motor with a Pratt & Whitney PT6 turboprop engine, putting out a massive 680 hp.

Almost the entire plane was upgraded, and the engineering that went into it is awe-inspiring, especially considering that [Mike] did most of it himself. This includes a redesigned fuel system, enlarged wing and control surfaces, new avionics, oxygen system, upgraded landing gear and an array of lights. The wing tip landing lights are actually from a Boeing 737. [Mike] estimates that the upgrades cost somewhere in the region of a million US dollars. All the highlights of the build is documented in series of videos on [Mike]’s YouTube channel. What we would give for a personal workshop like that…

Try not to let your jaw hit the floor when watching the video after the break.

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Rideable Tank Tread: It’s A Monotrack Motorcycle That Begs You To Stop Very Slowly

There will always be those of us who yearn for an iron steed and the wind through your hair. (Or over your helmet, if you value the contents of your skull.) If having fun and turning heads is more important to you than speed or practicality, [Make it Extreme] has just the bike for you. Using mostly scrapyard parts, they built a monotrack motorcycle — no wheels, just a single rubber track.

[Make it Extreme] are definitely not newcomers to building crazy contraptions, and as usual the entire design and build is a series of ingenious hacks complimented by some impressive fabrication skills. The track is simply a car tyre with the sidewalls cut away. It fits over a steel frame that can be adjusted to tension the track over a drive wheel and a series of rollers which are all part of the suspension system.

Power is provided by a 2-stroke 100cc scooter engine, and transmitted to the track through a drive wheel made from an old scuba tank. What puts this build over the top is that all of this is neatly located inside the circumference of the track. Only the seat, handlebars and fuel tank are on the outside of the track. The foot pegs are as far forward as possible, which helps keep your center of gravity when stopping. It’s not nearly as bad as those self-balancing electric monocycles, but planning stops well in advance is advisable.

While it’s by no means the fastest bike out there it definitely looks like a ton of fun. Build plans are available to patrons of [Make it Extreme], but good luck licensing one as your daily driver. If that’s your goal, you might want to consider adding a cover over the track between the seat and handlebars to prevent your khakis from getting caught on your way to the cubicle farm.

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