From Tube And Wing To Just Wing: The Future Of Airliners

August 8, 2021 by Danie Conradie 77 Comments

Airliners have become an unremarkable part of modern life, but unless you happen to be an aircraft enthusiast, you’d be forgiven for thinking the latest Airbus model looks more or less the same as the Boeing 707 that ushered in the Jet Age. But that might soon change, with blended wing airliners looking like the next step in air travel efficiency. In the video after the break, [Real Engineering] takes us on a fascinating tour of the past and possible future of jet airliners.

Contemporary airliners all still follow the same old “tube and wing” design, but have become vastly more efficient. The latest jetliners burn almost 50% less fuel per passenger-km than they did 50 years ago. This is thanks to better engines, improved aerodynamics, reduced weight, and a vast array of other, often invisible changes. However, it’s looking like a more drastic change is needed to keep the progress going, and NASA, Boeing, and Airbus are all betting on blended wing designs to do this.

Blended wing aircraft are basically flying wings, where the cargo-carrying section of aircraft is shorter, wider, and produces lift. This layout can be used to increase the aircraft’s internal volume, and improve aerodynamic losses, by eliminating the tail. Research shows that blended wing design could reduce fuel consumption by as much as 27%. Since load and produced lift are spread more evenly along the entire width of the aircraft, it also reduces the amount of structural reinforcement required for the wings, especially at the root. The large internal volumes also allow other power sources, like hydrogen fuel cells to be used.

Blended wing aircraft are not without challenges. They are inherently unstable and require complex control systems to fly. These control systems depend on sensors, actuators, and software to work properly, and require multiple levels of redundancy. The omission of these redundancies ultimately led to the 2008 crash of a B-2 bomber, and the more recent fatal crashes of Boeing’s 737 MAX airliners. Also, unlike tubular fuselages, blended wing designs are not ideal pressure vessels. However, this is not a major problem thanks to the availability of carbon composite materials to create strong, lightweight structures.

With aircraft technology moving as fast as ever, we look forward to seeing what the future will bring. Whether it’s personal rotorcraft or commercial space flight, it sure won’t be boring.

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Single-Wheel Motorcycle Trailer

August 2, 2021 by Danie Conradie 40 Comments

A motorbike might not take up a lot of parking space, but this is not true for the trailer required to transport one. To solve this problem, [Make It Extreme] built a custom single-wheel motorbike trailer barely wider than the motorcycle itself.

The frame of the trailer is welded together from a couple of sections of large diameter steel tube, with a single car wheel mounted to a C-shaped portion on the rear end. A standard ball hitch would allow the entire trailer to tilt over to one side, so a pin hitch is used instead, with a pivot to allow up and down movement. Another pivot was added to the frame just ahead of the rear wheel to allow the trailer to lower to the ground for loading. It is raised and lowered with a manually pumped hydraulic cylinder, and a small pivoting ramp at the back also acts as a stop for the motorbike’s rear wheel. With the rigid frame and no suspension, we’re just wondering how well it will handle bumps at high speed.

[Make It Extreme] really likes his recreational vehicles, which include a monotrack motorbike, a monowheel, and an all-terrain hoverboard, among others. Continue reading “Single-Wheel Motorcycle Trailer” →

British Big Rigs Are About To Go Green

July 31, 2021 by Jenny List 78 Comments

An increasing fact of life over the coming years will be the decarbonisation of our transport networks, for which a variety of competing solutions are being touted. Railways, trucks, cars, and planes will all be affected by this move away from fossil fuels, and while sectors such as passenger cars are making great strides towards electric drive, there remain some technical hurdles elsewhere such as with heavy road freight. To help inform the future of road transport policy in the UK then, the British government are financing a series of trials for transportation modes that don’t use internal combustion. These will include a battery-electric fleet for the National Health Service and a hydrogen-powered fleet in Scotland, as well as a trial of the same overhead-wire system previously given an outing in Germany, that will result in the electrification of a 12.4 mile section of the M180 motorway in Lincolnshire.

We’ve written about the overhead electrification project in Germany in the past and subjected it to a back-of-envelope calculation that suggested the total costs for a country such as the UK might be surprisingly affordable. The M180 is something of a backwater in the UK motorway network though, so it will be interesting to see how they approach the problem of finding real-world loads for their tests that ply such a short and isolated route. We’d expect the final picture to include all three technologies in some form, which can only be a good thing if it increases the available electric and hydrogen infrastructure. We’ll follow this story, though sadly we may not be able to blag a cab ride on the M180 in one of the trucks.

Bright Bike Light Might Make Them Back Off

July 29, 2021 by Kristina Panos 26 Comments

[Tegwyn☠Twmffat] recently got a job as a part-time bike courier and has come to realize just how dangerous it can be to mix leg-powered transportation with various sizes of engine-driven machinery. Some people would be content with a light, but why use a measly little bulb or two when you can have a giant, illuminated sign with a clear call to action? Because is there really any ceiling when it comes to safety precautions?

We think that 180 LEDs in a familiar formation oughta do it. An ultrasonic sensor detects cars behind the bike with the help of an Adafruit Feather. All those LEDs are controlled by a pair of L293 motor driver chips and a slide potentiometer for some dimming action. After all, they need to get enough juice to be visible in broad daylight, but also be dimmable so as not to blind people at night.

[Tegwyn☠Twmffat] calls this a simple project that is suitable for beginners. We think that is great, because bespoke safety measures should be accessible for everyone. So go get those Gerbers and make one for yourself! You can check it out in action on the back of a tricycle after the break.

Want a more relaxing ride? Recumbent is the reclined way to go.

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Swamp Gas Will Get You Home

July 28, 2021 by Jenny List 61 Comments

The energy to power a motorcycle has to come from somewhere, be it a power station, a solar panel, a gas station, or a hydrogen plant. There have been many ways to reduce the cost of extracting that energy over the years, but we think [Gijs Schalkx] may have hit upon one of the cheapest and simplest we’ve ever seen. It may not be free gas, but it is free swamp gas! His Uitsloot (we think that’s Dutch for “From the ditch”) motorcycle gets its power from methane generated in the sediment at the bottom of the Netherlands’ many waterways.

At its heart is a venerable Honda Cub moped, we’re guessing of the 50 cc version. On its pillion is a large clear container, inside of which is a balloon filled with gas. He doesn’t go into details in the video below the break, but we’re guessing he’s injecting the gas into the Honda’s airbox from which the engine can suck the gas/air mixture. We like his gas collector, a large inner tube with a collector funnel in its centre that floats on the water. He dons some waders and pokes the sediment with a long stick to release bubbles of methane. He then uses a long hose and a bicycle pump to inflate the balloon with the collected gas. We see him zipping around the streets of Arnhem under this unconventional power, though sadly we don’t see how far a full balloon will take him.

There’s a discussion to be had as to the environmental credentials of this project, but we think given that the naturally generated methane which would find its way into the atmosphere eventually has a greater effect on the climate than the CO2 produced by the engine, he may be onto a winner. It is however not a system that would scale to more than a few drivers poking at bogs with a stick.

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Repair Hack Saves Tesla Owner From Massive Bill

July 16, 2021 by Dan Maloney 74 Comments

As expensive as a new car is, it almost seems like a loss leader now to get you locked into exorbitantly expensive repairs at the dealership’s service department. That’s the reason a lot of us still try to do as much of the maintenance and repairs on our cars as possible — it’s just too darn expensive to pay someone else to do it.

Case in point: this story about a hapless Tesla owner who faced a massive repair bill on his brand new car. [Donald]’s tale of woe began when he hit some road debris with his two-wheel-drive Model 3. The object hit penetrated the plastic shield over the front of the battery pack, striking a fitting in the low-pressure battery cooling plumbing. The plastic fitting cracked, causing a leak that obviously needed repair. The authorized Tesla service center gave him the bad news: that he needed a new battery pack, at a cost of $16,000. Through a series of oversights, [Donald]’s comprehensive insurance on the car had lapsed, so he was looking at funding the repair, approximately half the cost of a new Model 3, out of pocket.

Luckily, he got in touch with [Rich Benoit] of The Electrified Garage, one of the few independent garages doing Tesla repairs and customizations. The video below is queued up to the part where they actually do the repair, which is ridiculously simple. After cutting off the remains of the broken fitting with a utility knife, [Rich]’s tech was able to cut a thread in both the fitting and the battery pack, and attach them together with a brass nipple from the plumbing section of the local home store. The total bill for the repair was $700, which still seems steep to us, but a far cry from what it could have been.

Hats off to [Rich] and his crew for finding a cost-effective workaround for this issue. And if you think you’ve seen his EV repairs before, you’re right. Of course, some repairs are more successful than others.

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Down The Fabrication Rabbit Hole To Build A Recumbent Bike

July 14, 2021 by Mike Szczys 13 Comments

‘Tis the time of the year to find as many reasons as possible to shut off the smartphone and get yourself outside. [Rich Olson’s] newest excuse is a recumbent bicycle he built from at least three donor bikes. Of course we’ve seen any number of bike mods over the years (the tall bikes that integrate a ladder to climb up to the saddle have always held a special place in our hearts), but [Rich] left us a nice trail of bread crumbs on how to get into this yourself without breaking the bank.

He worked from a set of open source plans, with additional instructions laid out by [Brian in Ohio] in a bicycle hacking series on the Hacker Public Radio podcast. We learn in the first installment that you can get your hands on a torch that uses oxygen and MAP gas to braze the pipe joints — a quick Duck Duck Go search turns up kits that have the torch and both gases for about eighty bucks. Ask around your neighbourhood and you’re likely to find some bike frames from the disused and broken cycles lurking in dark garage corners. That first podcast page even has images that show you how to lay out fishmouth cuts where the tubes will meet.

But what really grabbed our attention is the tube bending for the recumbent seat. This is a speciality part that you’re not going to be able to salvage from traditional bikes. [Rich’s] project shows off this image of a bend template and the two main rails he used from the seat; but how did he make those bends? The third episode of [Brian in Ohio’s] series covers the one simple trick that electricians don’t want you to know. Those rails are made out of electrical conduit and you can easily buy/rent/borrow a commonplace conduit bending tool which has the handy advantage of including angle guides.

You’ll find [Rich’s] video after the break which begins with a slideshow and ends with a demo ride. That lets us see the lacing on the back side of the seat fabric that keeps it taught, yet comfy in a way a standard bike saddle just can’t be.

If this still hasn’t convinced you to pick up a torch, you can also build a recumbent with a wooden frame.

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