The Rotary-X Engine Is A Revolution In Thermodynamics

February 15, 2021 by Kristina Panos 119 Comments

If you’re running an army, chances are good that you need a lot of portable power for everything from communications to weapons control systems. When it comes to your generators, every ounce counts. The smaller and lighter you can get them, the better.

Connecticut-based company LiquidPiston is developing a high-powered generator for the US Army that uses the company’s own rotary x-engine — a small, light, and powerful beast that sounds like a dream come true. It can run on gasoline, diesel, natural gas, kerosene, or jet fuel, and is scalable from 1 to 1,000 horsepower (PDF).

Co-founder and CEO Alex Schkolnik describes the design as a combination of the best parts of the Otto and Atkinson cycle engines, the Diesel, and the Wankel rotary while solving the big problems of the latter two. That sounds impressive, but it doesn’t mean much unless you understand how each of these engines work and what their various advantages and disadvantages are. So let’s take a look under the hood, shall we?

Continue reading “The Rotary-X Engine Is A Revolution In Thermodynamics” →

Europa Decision Delivers Crushing Blow To NASA’s Space Launch System (SLS)

February 12, 2021 by Tom Nardi 110 Comments

These days, NASA deciding to launch one of their future missions on a commercial rocket is hardly a surprise. After all, the agency is now willing to fly their astronauts on boosters and spacecraft built and operated by SpaceX. Increased competition has made getting to space cheaper and easier than ever before, so it’s only logical that NASA would reap the benefits of a market they helped create.

So the recent announcement that NASA’s Europa Clipper mission will officially fly on a commercial launch vehicle might seem like more of the same. But this isn’t just any mission. It’s a flagship interplanetary probe designed to study and map Jupiter’s moon Europa in unprecedented detail, and will serve as a pathfinder for a future mission that will actually touch down on the moon’s frigid surface. Due to the extreme distance from Earth and the intense radiation of the Jovian system, it’s considered one of the most ambitious missions NASA has ever attempted.

With no margin for error and a total cost of more than $4 billion, the fact that NASA trusts a commercially operated booster to carry this exceptionally valuable payload is significant in itself. But perhaps even more importantly, up until now, Europa Clipper was mandated by Congress to fly on NASA’s Space Launch System (SLS). This was at least partly due to the incredible power of the SLS, which would have put the Clipper on the fastest route towards Jupiter. But more pragmatically, it was also seen as a way to ensure that work on the Shuttle-derived super heavy-lift rocket would continue at a swift enough pace to be ready for the mission’s 2024 launch window.

But with that deadline fast approaching, and engineers feeling the pressure to put the final touches on the spacecraft before it gets mated to the launch vehicle, NASA appealed to Congress for the flexibility to fly Europa Clipper on a commercial rocket. The agency’s official line is that they can’t spare an SLS launch for the Europa mission while simultaneously supporting the Artemis Moon program, but by allowing the Clipper to fly on another rocket in the 2021 Consolidated Appropriations Act, Congress effectively removed one of the only justifications that still existed for the troubled Space Launch System.

Continue reading “Europa Decision Delivers Crushing Blow To NASA’s Space Launch System (SLS)” →

Linux Fu: Serial Untethered

February 11, 2021 by Al Williams 28 Comments

Serial ports used to be everywhere. In a way, they still are since many things that appear to plug in as a USB device actually look like a serial port. The problem is that today, the world runs on the network. Sure, you can buy a terminal server that converts a serial port to an Ethernet port, but what fun is that? In this article, I’m going to show you how to stream serial ports over the network using some available Linux tools. It isn’t perfect, and it won’t work for every case, but when it works it works well.

Everything is a File, Until it Isn’t

At some point in the past, Unix — the progenitor of Linux — treated virtually everything as a file, and all files were created more or less equal. Programs didn’t care if a file was local, on the network, from a tape drive, or arriving over a named pipe.

But things started to change. Even though a serial port is just a file under Linux, it has some special attributes that let you set, for example, baud rates. Worse, some programs “know” too much about files and insist on certain naming conventions. So, in theory, you should be able to create a network socket, connect one end to a serial port and the other end to a program, and be done with it. In theory.

Continue reading “Linux Fu: Serial Untethered” →

Tesla Recalls Cars With EMMC Failures, Calls Part A ‘Wear Item’

February 11, 2021 by Zoe Skyforest 150 Comments

It’s a problem familiar to anyone who’s spent a decent amount of time playing with a Raspberry Pi – over time, the flash in the SD card reaches its write cycle limits, and causes a cavalcade of confusing errors before failing entirely. While flash storage is fast, compact, and mechanically reliable, it has always had a writeable lifespan much shorter than magnetic technologies.

Flash storage failures in the computer behind Tesla’s famous touch screen are causing headaches for drivers.

Of course, with proper wear levelling techniques and careful use, these issues can be mitigated successfully. The surprising thing is when a major automaker fails to implement such basic features, as was the case with several Tesla models. Due to the car’s Linux operating system logging excessively to its 8 GB eMMC storage, the flash modules have been wearing out. This leads to widespread failures in the car, typically putting it into limp mode and disabling many features controlled via the touchscreen.

With the issue affecting important subsystems such as the heater, defroster, and warning systems, the NHTSA wrote to the automaker in January requesting a recall. Tesla’s response acquiesced to this request with some consternation, downplaying the severity of the issue. Now they are claiming that the eMMC chip, ball-grid soldered to the motherboard, inaccessible without disassembling the dash, and not specifically mentioned in the owner’s manual, should be considered a “wear item”, and thus should not be subject to such scrutiny. Continue reading “Tesla Recalls Cars With EMMC Failures, Calls Part A ‘Wear Item’” →

The $50 Ham: Digital Modes With WSJT-X

February 10, 2021 by Dan Maloney 33 Comments

As it is generally practiced, ham radio is a little like going to the grocery store and striking up a conversation with everyone you bump into as you ply the aisles. Except that the grocery store is the size of the planet, and everyone brings their own shopping cart, some of which are highly modified and really expensive. And pretty much every conversation is about said carts, or about the grocery store itself.

With that admittedly iffy analogy in mind, if you’re not the kind of person who would normally strike up a conversation with someone while shopping, you might think that you’d be a poor fit for amateur radio. But just because that’s the way that most people exercise their ham radio privileges doesn’t mean it’s the only way. Exploring a few of the more popular ways to leverage the high-frequency (HF) bands and see what can be done on a limited budget, in terms of both cost of equipment as well as the amount of power used, is the focus of this installment of The $50 Ham. Welcome to the world of microphone-optional ham radio: weak-signal digital modes.

Continue reading “The $50 Ham: Digital Modes With WSJT-X” →

Would You Like Fries With Your Insect Burger, Ma’am?

February 10, 2021 by Jenny List 167 Comments

A trip to a supermarket is a rare luxury in a pandemic lockdown, but were I to cruise the aisles with my basket today I’d probably come away with a healthy pile of fruit and veg, a bit of meat and fish, and maybe some cheese. My shopping basket in 2031 though might have a few extras, and perhaps surprisingly some of them might be derived from insects. That’s a future made a little closer, by EU scientists declaring that farmed insect products are safe for humans and animals to eat.

Global map showing meat consumption in 2013 — Is meat consumption at this level sustainable? Our World In Data, CC BY 3.0.

We humans, like some of our fellow great ape cousins, are omnivores. We can eat anything, even if we might not always want to eat some things twice. As such, the diets of individual populations would in the past have varied hugely depending on the conditions that existed wherever they lived, giving us the ability to spread to almost anywhere on the planet — and we have.

Over the past few hundred years this need to subsist only on foods locally available has been marginalized by advances in agriculture. For those of us in developed countries, any foodstuff that takes our fancy can be ours for a trivial effort. This has meant an explosion of meat consumption as what was once a luxury food has become affordable to the masses, and in turn a corresponding agricultural expansion to meet demand that has placed intolerable stresses on ecosystems and is contributing significantly to global warming. It’s very clear that a mass conversion to veganism is unlikely to take place, so could farmed insects be the answer to our cravings for meat protein? It’s likely to be a tough sell to consumers, but it’s a subject that bears more examination. Continue reading “Would You Like Fries With Your Insect Burger, Ma’am?” →

The Modding, Restoration, And Demise Of A $3M Analog Computer

February 9, 2021 by Chris Lott 24 Comments

How do you rapidly record the output from your three million dollar analog computer in the 1940s when the results are only available on analog meters? The team responsible for the Westinghouse 1947 AC Network Calculator at Georgia Tech was faced with just this problem and came up with a nifty solution — hack the control panel and wire in a special-purpose drafting table.

What Is It?

What is this beast of a computer? Machines of this type were developed during and after World War 2, and strictly speaking, belong in the category of scale models rather than true computers. Although these machines were very flexible, they were primarily designed to simulate power distribution grids. There is a lot of theory under the hood, but basically a real world, multi-phase distribution system would be scaled to single-phase at 400 Hz for modeling.

The engineers would “program” the machine by connecting together the appropriate circuit elements (like capacitors, inductors, transmission lines, generators, etc.) on big patch panels. Thus programmed, a 10 kW motor-generator located in the basement would be started up and the simulation was underway. Continue reading “The Modding, Restoration, And Demise Of A $3M Analog Computer” →