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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Unconventional Drone Uses Gas Thrusters For Control

You’ve got to hand it to [Tom Stanton] – he really thinks outside the box. And potentially outside the atmosphere, to wit: we present his reaction control gas thruster-controlled drone.

Before anyone gets too excited, [Tom] isn’t building drones for use in a vacuum, although we can certainly see a use case for such devices. This is more of a hybrid affair, with counter-rotating props mounted in a centrally located duct providing the lift and the yaw control. Flanking that is a triangular frame supporting three two-liter soda bottle air reservoirs, each of which supplies a down-firing nozzle at each apex of the triangle. Solenoid valves control the flow of compressed air from the bottles to the nozzles, providing thrust to stabilize the roll and pitch axes. As there aren’t many off-the-shelf flight control systems set up for reaction control, [Tom] had to improvise thruster control; an Arduino watches the throttle signals normally sent to a drone’s motors and fires the solenoids when they get to a preset threshold. It took some tuning, but [Tom] was eventually able to get a stable, untethered hover. And he’s right – the RCS jets do sound amazing when they’re firing, as long as the main motors are off.

This looks as though it has a lot of potential, and we’d love to see it developed more. It reminds us a bit of this ducted-prop drone, another great example of stretching conventional drone control concepts to the limit.

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Air-Breathing Rocket Engine Promises Future Space Planes

If you are a certain age, you probably remember the promise of supersonic transports. The Concorde took less than 4 hours to go across the Atlantic, but it stopped flying in 2003 and ended commercial supersonic passenger flights  But back in the 1970s, we thought the Concorde would give way not to older technology, but to newer. After all, man had just walked on the moon and suborbital transports could make the same trip in 30 minutes and — according to Elon Musk — go between any two points on the Earth in an hour or less. A key component to making suborbital flights as common as normal jet travel is a reasonable engine that can carry a plane to the edge of space. That’s where the UK’s Sabre engine comes into play. Part jet and part rocket, the engine uses novel new technology and two different operating modes to power the next generation of spaceplane. The BBC reports that parts of the new engine will undergo a new phase of testing next month.

The company behind the technology, Reaction Engines, Ltd, uses the engine in an air-breathing jet mode until it hits 5.5 times the speed of sound. Then the same engine becomes a rocket and can propel the vehicle at up to 25 times the speed of sound.

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Marines 3D-Print Part To Repair Multi-Million Dollar Fighter

The good news: all you need to complete the repair you’re working on is one small part. The bad news: it’s only available in a larger, expensive assembly. The worst news: shipping time is forever. We’ve all been there, and it’s a hard pill to swallow for the DIYer. Seems like a good use case for 3D-printing.

Now imagine you’re a US Marine, and instead of fixing a dishwasher or TV remote, you’ve got a $123 million F-35 fighter in the shop. The part you need is a small plastic bumper for the landing gear door, but it’s only available as part of the whole door assembly, which costs $70,000 taxpayer dollars. And lead time to get it shipped from the States is measured in weeks. Can you even entertain the notion of 3D-printing a replacement? It turns out you can, and it looks like there will be more additive manufacturing to come in Corps repair depots around the world.

Details of the printed part are not forthcoming for obvious reasons, but the part was modeled in Blender and printed in PETG on what appears to be a consumer-grade printer. The part was installed after a quick approval for airworthiness, and the grounded fighter was back in service within days. It’s encouraging that this is not a one-off; other parts have been approved for flight use by the Marines, and a whole catalog of printable parts for ground vehicles is available too. This is the reality that the 3D printing fiction of Lost in Space builds upon.

And who knows? Maybe there are field-printable parts in the disposable drones the Corps is using for standoff resupply missions.

[via 3D-Printing Industry]

Fire. Vortex. Cannon. Need We Say More?

Tornadoes are a rightfully feared natural disaster. Fire tornadoes are an especially odious event to contend with — on top of whatever else is burning. But, a fire vortex cannon? That’s some awesome eye candy.

The madman behind this cannon belching huge gouts of fire is none other than Youtuber [JAIRUS OF ALL]. This build is actually an upgrade to one of his previous projects — a fire tornado gun that burned itself out and is now twice-revived — and is arguably better at creating a proper vortex to direct the flames. Built around a modified NERF gun, a pair of 60mm electric ducted fans with some additional venting — and tunable via a speed controller — direct the airflow through slits in a vortex chamber. A backpack of liquid propane literally fuels this phoenix of a flamethrower, so [JAIRUS] had plenty of time to put together some great footage. Check it out!

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Delightful Electromechanical Build Of A Jet Engine Model

[InterlinkKnight]’s jet engine model is a delight to behold and to puzzle out. Many of us have been there before. We know how to build something, we know it’s not the most up-to-date approach, but we just can’t help ourselves and so we go for it anyway. The result is often a fun and ingenious mix of the mechanical and the electrical. His electric jet engine model is just that.

Being a model, this one isn’t required to produce any useful thrust. But he’s made plenty of effort to make it behave as it should, right down to adding a piece of plastic to rub against a flywheel gear in order to produce the perfect high-pitched sound, not to forget the inclusion of the flywheel itself to make the turbine blades gradually slow down once the motor’s been turned off. For the N1 gauge (fan speed gauge) he built up his own generator around the motor shaft, sending the output through rectifying diodes to a voltmeter.

But the most delightful of all has to be the mechanical linkages for the controls. The controls consist of an Engine Start switch, Fuel Control switch and a throttle lever and are all built around a rheostat which controls the motor speed. The linkages are not pretty, but you have to admire his cleverness and just-go-for-it attitude. He must have done a lot of head scratching while getting it to all work together. We especially like how flipping the Fuel Control switch from cutoff to run levers the rheostat with respect to its dial just a little, to give a bit of extra power to the engine. See if you can puzzle it out in his Part 3 video below where he removes the cover and walks through it all.

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