A Modular Ecosystem That Evolved Around A Simple Diesel Engine

October 6, 2019 by Roger Cheng 20 Comments

High volume commodity products are a foundation of hacking, we’ve built many projects around popular form factors like NEMA 17 stepper motors, 608 bearings, and 280 DC motors. Their high volume led to lower cost, which further increased popularity, and the cycle repeats. A similar thing happened to a style of single-cylinder diesel engine in China, and [Jalopnik] takes us through an exploration of these “Tuo La Ji” (tractor) machines.

Like many popular standards, circumstances elevated this style of engine to become more popular than its peers. Judging from the pictures, the idea is similar to NEMA 17 in that the core essence is a bolt pattern and an output shaft. Different manufacturers offer various capabilities within this space, and a wild assortment of machinery evolved to take advantage of this class of power source.

It starts with a set of wheels and handlebars to create a walk-behind farm tractor, something pretty common around the world. But this particular ecosystem grew far beyond that to many other applications, including full sized trucks with off-road capability that would embarrass most of the genteel SUVs cruising our roads today. They may not be fast, but they only needed to be faster and have longer endurance than beasts of burden to be effective as “a horseless horse”.

Due to factors such as poor crash safety, absence of diesel emission controls, and affordability of more powerful (and faster!) vehicles, these machines are a dying breed. But that won’t change the fact there was a fantastic amount of mechanical hacking ingenuity that had sprung up around this versatile engine building simple and effective machines. Their creativity drew from the same well that fed into these Indonesian Vespas.

Photo by [Brian Holsclaw] CC BY-ND 2.0

Indonesian Jungle Vespas

October 4, 2019 by Sharon Lin 10 Comments

Typically, we associate Vespas with Italians, riding their posh scooters midday under the heat of the Mediterranean sun. In one community, however, the riders and vehicles are pretty different – and by that we mean a whole lot different. Think Mad Max: Fury Road meets The Jungle Book.

The first Vespa arrived in Indonesia in the 1960s when the vehicles were rewarded to Indonesian peacekeepers returning from a mission in Africa. While many of the Vespas on the archipelago maintain the same classic style, some riders have modified theirs into entirely new conceptions.

Indonesian photographer [Muhammad Fadli] captures these riders on their Vespa sampah (“garbage Vespa”) and Vespa gembel (“Vespa drifter”), as they are known by locals. The unique design of the riders is partially attributed to their emergence in the early 2000s coinciding with the fall of the Soeharto authoritarian regime. The newfound freedom and self expression, as well as the relaxed law enforcement, contributed to the development of new types of modified vehicles on the road.

While the scooters are widespread, there isn’t any known count of extreme Vespas in the country. Most of the Vespas are not meant for riding, but rather to show off their physical form. While some are made from cheap steel frames and tires, others are adorned with road scraps and symbols. Anything from buffalo skeletons to machine gun rounds are used to accentuate the design of the scooters, many of which have a punk or metal vibe.

Within the community, there are annual extreme Vespa gatherings, which can draw thousands of riders from all over Indonesia. From frames made of bamboo to frames made of garbage, stalls that collect recyclables to add to their vehicles, and riders from all walks of life, there’s no apparent limit to the builders’ creativity.

[Thanks edmonkey for the tip!]

Build Your Own Solenoid Engine

September 25, 2019 by Bryan Cockfield 13 Comments

A solenoid engine is a curiosity of the electrical world. By all measures, using electricity to rotate something can be done almost any other way with greater efficiency and less hassle. But there’s just something riveting about watching a solenoid engine work. If you want to build one of your own and see for yourself, [Emiel] aka [The Practical Engineer] has a great how-to.

For this build though he used a few tools that some of us may not have on hand, such as a lathe and a drill press. The lathe was used to make the plastic spool to hold the wire, and also to help wind the wire onto the spool itself rather than doing it by hand. He also milled the wood mounts and metal bearings as well, and the quality of the work really shows through in the final product. The final touch is the transistor which controls power flow to the engine.

If you don’t have all of the machine tools [Emiel] used it’s not impossible to find substitute parts if you want to build your own. It’s an impressive display piece, or possibly even functional if you want your build to have a certain steampunk aesthetic (without the steam). You can even add more pistons to your build if you need extra power.

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3D Printing May Be The Key To Practical Scramjets

September 3, 2019 by Tom Nardi 32 Comments

The first scramjet, an airbreathing jet engine capable of pushing an aircraft beyond Mach 5, was successfully flown in the early 1990s. But while pretty much any other technology you could imagine has progressed by leaps and bounds in the nearly 30 years that have passed, the state-of-the-art in hypersonic scramjets hasn’t moved much. We still don’t have practical hypersonic aircraft, military or otherwise, and any missiles that travel at those sort of speeds are rocket powered.

This is somewhat surprising since, at least on paper, the operating principle of the scramjet is simplicity itself. Air rushing into the engine is compressed by the geometry of the inlet, fuel is added, the mixture is ignited, and the resulting flow of expanded gases leaves the engine faster than it entered. There aren’t even any moving parts inside of a scramjet, it’s little more than a carefully shaped tube with fuel injectors and ignitors in it.

Unfortunately, pulling it off in practice is quite a bit harder. Part of the problem is that a scramjet doesn’t actually start working until the air entering the engine’s inlet is moving at around Mach 4, which makes testing them difficult and expensive. It’s possible to do it in a specially designed wind tunnel, but practically speaking, it ends up being easier to mount the engine to the front of a conventional rocket and get it up to speed that way. The downside is that such flights are one-way tickets, and end with the test article crashing into the ocean once it runs out of fuel.

But the bigger problem is that the core concept is deceptively simple. It’s easy to say you’ll just squirt some jet fuel into the stream of compressed air and light it up, but when that air is moving at thousands of miles per hour, keeping it burning is no small feat. Because of this, the operation of a scramjet has often been likened to trying to light a match in a hurricane; the challenge isn’t in the task, but in the environment you’re trying to perform it in.

Now, both Aerojet Rocketdyne and Northrop Grumman think they may have found the solution: additive manufacturing. By 3D printing their scramjet engines, they can not only iterate through design revisions faster, but produce them far cheaper than they’ve been able to in the past. Even more importantly, it enables complex internal engine geometries that would have been more difficult to produce via traditional manufacturing.

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Putting Carbs On A Miata, Because It’s Awesome

August 8, 2019 by Lewin Day 100 Comments

Carburettors versus electronic fuel injection (EFI); automotive fans above a certain age will be well versed in the differences. While early EFI systems had their failings, the technology brought with it a new standard of reliability and control. By the early 1990s, the vast majority of vehicles were sold with EFI, and carburettors became a thing of the past.

The Mazda Miata was no exception. Shipping in 1989, it featured not only multiport fuel injection, but also a distributorless ignition system. Consisting of two coilpacks in a wasted spark configuration, with computer-controlled timing, the system was quite advanced for its time, especially for a budget sports car.

Despite the Miata’s technological credentials, those in the modified car scene tend to go their own way. A man by the name of Evan happened to be one such individual and decided to do just this — scrapping the EFI system and going with a retro carburetor setup. It was around this point that this I got involved, and mechanical tinkering ensued.

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NASA’s “Green” Fuel Seeks Safer Spaceflight By Finally Moving Off Toxic Hydrazine

July 1, 2019 by Tom Nardi 35 Comments

Spaceflight is inherently dangerous. It takes a certain type of person to willingly strap into what’s essentially a refined bomb and hope for the best. But what might not be so obvious is that the risks involved aren’t limited to those who are personally making the trip. The construction and testing of space-bound vehicles poses just as much danger to engineers here on the ground as it does to the astronauts in orbit. Arguably, more so. Far more individuals have given their lives developing rocket technology than have ever died in the cockpit of one of them.

Reddish brown exhaust of hydrazine thrusters

Ultimately, this is because of the enormous amount of energy stored in the propellants required to make a rocket fly. Ground support personnel need to exercise great care even when dealing with “safe” propellants, such as the classic combination of kerosene and liquid oxygen. On the other end of the spectrum you have chemicals that are so unstable and toxic that they can’t be handled without special training and equipment.

One of the most dangerous chemicals ever used in rocket propulsion is hydrazine; and yet from the Second World War to the present day, it’s been considered something of an occupational hazard of spaceflight. While American launch vehicles largely moved away from using it as a primary propellant, hydrazine is still commonly used for smaller thrusters on spacecraft.

When SpaceX’s Crew Dragon exploded in April during ground tests, the release of approximately one and a half tons of hydrazine and nitrogen tetroxide propellants required an environmental cleanup at the site.

But soon, that might change. NASA has been working on a project they call the Green Propellant Infusion Mission (GPIM) which is specifically designed to reduce modern spacecraft’s dependency on hydrazine. In collaboration with the Air Force Research Laboratory at California’s Edwards Air Force Base, the space agency has spearheaded the development of a new propellant that promises to not just replace hydrazine, but in some scenarios even outperform it.

So what’s so good about this new wonder fuel, called AF-M315E? To really understand why NASA is so eager to power future craft with something new, we first have to look at the situation we’re in currently.

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Building A Turbocharger Turbojet

March 25, 2019 by Lewin Day 17 Comments

Jet engines are known to be highly demanding machines, requiring the utmost attention to tolerances, material specifications, and operating regimes. If any of these parameters are ignored, failures can be catastrophic and expensive. Despite these exacting requirements, it is possible to build a jet engine in the home workshop – and using a turbocharger is a great way to do that. (Video also embedded after the break.)

[Tech Ingredients] does a great job of discussing the basic concepts behind the turbocharger jet engine build, and how various parameters impact performance and efficiency. Through the use of various rules of thumb, developed over years of experimentation by home builders and engineers alike, it’s possible to whip up a functioning engine without too much trial and error. The video breaks down and discusses the thermodynamics at play, as well as practical considerations like cooling and lubrication, in several easy to digest steps.

Jet engines are a popular high-octane build, and we’ve seen it pulled off before by makers like [Colin Furze]. The trick is to pull it off without causing yourself serious injury.

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