Surfboard Gets Jet Upgrades

Surfing is a fun and exciting sport but a lot of beginners can get discouraged with how little time is spent actually riding waves while learning. Not only are balance and wave selection critical skills that take time to learn, but a majority of time in the water is spent battling crashing waves to get out past the breakers. Many people have attempted to solve this problem through other means than willpower alone, and one of the latest attempts is [Andrew W] with a completely DIY surfboard with custom impeller jet drives.

The surfboard is hand-made by [Andrew W] himself using a few blocks of styrofoam glued together and then cut into a generic surfboard shape. After the rough shaping is done, he cuts out a huge hole in the back of the board for the jet drive. This drive is almost completely built by [Andrew] as well including the impeller pumps themselves which he designed and 3D printed. The pair of impellers are driven by some beefy motors and a robust speed controller that connects wirelessly to a handheld waterproof throttle to hold while surfing. Once everything was secured in the motor box the surfboard was given a final shaping and then glassed. The final touch was an emergency disconnect attached to a leash so that if he falls off the board it doesn’t speed away without him.

The build is impressive not only for [Andrew]’s shaping skills but for his dedication to a custom jet drive for the surfboard. He spent over a year refining the build and actually encourages people not to do this as he thinks it took too much time and effort, but we’re going to have to disagree with him there. Even if you want to try to build something a lot simpler, builds like these look like a lot of fun once they’re finished. The build seems flawless and while he only tested it in a lake we’re excited to see if it holds up surfing real waves in an ocean.

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Waterjet-Powered Speedboat For Fun And Research

There are a lot of cliches about the perils of boat ownership. “The best two days of a boat owner’s life are the day they buy their boat, and the day they sell it” immediately springs to mind, for example, but there is a loophole to an otherwise bottomless pit of boat ownership: building a small robotic speedboat instead of owning the full-size version. Not only will you save loads of money and frustration, but you can also use your 3D-printed boat as a base for educational and research projects.

The autonomous speedboats have a modular hull design to make them easy to 3D print, and they use a waterjet for propulsion which improves their reliability in shallow waters and reduces the likelihood that they will get tangled on anything or injure an animal or human. The platform is specifically designed to be able to house any of a wide array of sensors to enable people to easily perform automated tasks in bodies of water such as monitoring for pollution, search-and-rescue, and various inspections. A monohull version with a single jet was prototyped first, but eventually a twin-hulled catamaran with two jets was produced which improved the stability and reliability of the platform.

All of the files needed to get started with your own autonomous (or remote-controlled) speedboat are available on the project’s page. The creators are hopeful that this platform suits a wide variety of needs and that a community is created of technology enthusiasts, engineers, and researchers working on autonomous marine robotic platforms. If you’d prefer to ditch the motor, though, we have seen a few autonomous sailboats used for research purposes as well.

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Fueling Up For Fusion: MAST’s Super-X, JET’s Deuterium-Tritium Experiments For ITER, And More

We’ve had nuclear fission reactors in operation all over the world for ages, but nuclear fusion always seems to be a decade or two away. While one cannot predict when we’ll reach the goal of sustained nuclear fusion, the cutting edge in test hardware is advancing at a rapid pace that makes us optimistic. Beginning as soon as this month and extending over a few years, we’re living through a very exciting time for nuclear fusion and plasma physics.

The Mega Ampere Spherical Tokamak (MAST) got a big upgrade to test a new cooled divertor design. JET (Joint European Torus) will be testing the deuterium-tritium fuel mixture that will be powering the ITER (the research project whose name began as an acronym for International Thermonuclear Experimental Reactor but has since been changed to just ITER). And the Wendelstein 7-X stellarator is coming back online with upgraded cooled divertors by next year.

Here the MAST Upgrade’s Super-X divertors have so far shown a ten-fold decrease in the temperature which the divertor is exposed to while carrying thermal energy out of the tokamak reactor. This means a divertor design and ultimately a fusion reactor that will last longer between maintenance sessions. On the stellarator side of things, Wendelstein 7-X’s new divertors may allow it to demonstrate the first continuous operation of a stellarator fusion reactor. Meanwhile, JET’s fuel experiments should allow us to test the deuterium-tritium fuel while ITER is working towards first plasma by 2025.

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Prototyping A Turbojet Engine In The Home Shop

The development of the turbojet engine was a gamechanger in aviation, as no longer would aircraft designers have to struggle with ever larger and more complex piston engines, nor would propellers keep planes stuck below the speed of sound. However, the turbojet is an exacting device, demanding the utmost of materials in order to work successfully. [Integza] discovered just this in his quest to build one at home.

Unlike most home jet engine builds, this one doesn’t use a turbocharger or go with a simpler pulse jet design – though [Integza] has built those, too. This is a proper radial-flow turbojet design. The build uses a 3D-printed compressor, which is possible as it doesn’t have to deal with much heat. However, for the turbine, [Integza] realised that plastic wouldn’t cut it. After experiments with ceramic resins failed too, a 3D printed jig was instead built to allow sheet metal to easily be crafted into a workable turbine. Other internal components were made out of concrete for heat resistance, and a combustion chamber welded up out of steel.

The engine did run after several attempts, albeit for just ten seconds before components started to melt. While the engine is a long way off being flight ready, it goes to show just how hard it is to build even a bench-running turbojet. Even major world powers have struggled with this problem over the years. Video after the break.

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Jet Powered Go Kart Built With RC Gear

Turbine cars never quite came to be, despite many experiments in the 20th century. Despite their high power output for their size, they’re just not well suited to land transport applications; even the M1A1 tank has been much maligned for its turbine power plant. That didn’t stop [Warped Perception] for throwing a jet on the back of a kart though, and it looks like a whole lot of fun. (Video, embedded below.)

The build starts with a garden variety gokart, with the piston engine and all associated running gear stripped off in haste. The RC-sized turbo jet is then mounted on an elegant aluminium bracket, neatly welded on to the back of the car. It’s hooked up with its electronic controller, with throttle controlled by an RC transmitter. It’s not ideal trying to steer one-handed with another on the stick, but these are the sacrifices made when parts don’t arrive in time.

Early testing revealed issues with air ingestion into the fuel line over bumps, but overall performance was impressive. Future plans involve a top speed run which we can’t wait to see. Of course, if it’s not outrageous enough for your taste, consider [Colin Furze’s] pulsejet build.

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80 Years From Invention, China Is Struggling With Jet Engines

The jet engine has a long and storied history. Its development occurred spontaneously amongst several unrelated groups in the early 20th Century. Frank Whittle submitted a UK patent on a design in 1930, while Hans von Ohain begun exploring the field in Germany in 1935. Leading on from Ohain’s work, the first flight of a jet-powered aircraft was in August 27, 1939. By the end of World War II, a smattering of military jet aircraft had entered service, and the propeller was on the way out as far as high performance aviation is concerned.

With the invention of the jet engine so far in the past, one could be forgiven for thinking that the technology has long been mastered around the world. However, recent reports show that’s not the case. China is a great example, facing issues with the development of jet engines for their indigenous military aircraft.

Closely Guarded Secrets

China’s development of ballpoint pen tips was a national news story in 2017. Source: Xinhua

In the age of the Internet and open source, technology moves swiftly around the world. In the consumer space, companies are eager to sell their product to as many customers as possible, shipping their latest wares worldwide lest their competitors do so first. In the case of products more reliant on infrastructure, we see a slower roll out. Hydrogen-powered cars are only available in select regions, while services like media streaming can take time to solve legal issues around rights to exhibit material in different countries. In these cases, we often see a lag of 5-10 years at most, assuming the technology survives to maturity.

In most cases, if there’s a market for a technology, there’ll be someone standing in line to sell it. However, some can prove more tricky than others. The ballpoint pen is one example of a technology that most of us would consider quaint to the point of mediocrity. However, despite producing over 80% of the world’s ballpoint pens, China was unable to produce the entire pen domestically. Chinese manufactured ballpoint tips performed poorly, with scratchy writing as the result. This attracted the notice of government officials, which resulted in a push to improve the indigenous ballpoint technology. In 2017, they succeeded, producing high-quality ballpoint pens for the first time.

The secrets to creating just the right steel, and manipulating it into a smooth rolling ball just right for writing, were complex and manifold. The Japanese, German, and Swiss companies that supplied China with ballpoint tips made a healthy profit from the trade. Sharing the inside knowledge on how it’s done would only seek to destroy their own business. Thus, China had to go it alone, taking 5 years to solve the problem.

There was little drive for pen manufacturers to improve their product; the Chinese consumer was more focused on price than quality. Once the government made it a point of national pride, things shifted. For jet engines, however, it’s somewhat of a different story.

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3D Printed Pulsejet Uses Tesla Valve

For most people, a jet is a jet. But there are several different kinds of jet engines, depending on how they operate. You frequently hear about ramjets, scramjets, and even turbojets. But there is another kind — a very old kind — called a pulsejet. [Integza] shows how he made one using 3D printed parts and also has a lot of entertaining background information. You can see the video below. (Beware, there is a very little bit of off-color language and humor in the video, so you might not want to watch this one at work.)

They are not ideal from a performance standpoint, but they are easy to make. How easy? A form of pulsejet was accidentally discovered by a young Swiss boy playing with alcohol in the early 1900s. Because of their simplicity, they’ve been built by lots of different people, including rocket pioneer Robert Goddard, who mounted one to a bicycle.

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