In a modern car, your speedometer might look analog, but it is almost certainly digital and driven by the computer that has to monitor all sorts of things anyway. But how did they work before your car was a rolling computer complex? The electronic speedometer has been around for well over a century and, when you think about it, qualifies as a technlogical marvel.
If you already know how they work, this isn’t a fair question. But if you don’t, think about this. Your dashboard has a cable running into it. The inner part of the cable spins at some rate, which is related to either the car’s transmission or a wheel sensor. How do you make a needle deflect based on the speed?
Since the very beginning, solid-propellants have been the cornerstone of amateur rocketry. From the little Estes rocket picked up from the toy store, to vehicles like the University of Southern California’s Traveler IV that (probably) crossed the Kármán line in 2019, a rapidly burning chunk of solid propellant is responsible for pushing them skyward. That’s not to say that amateur rockets powered by liquid propellants are completely unheard of … it’s just that getting them right is so ridiculously difficult that comparatively few have been built.
But thanks to [Half Cat Rocketry], we may start to see more hobbyists and students taking on the challenge. Their Mojave Sphinx liquid-fueled rocket is not only designed to be as easy and cheap to build as possible, but it’s been released as open source so that others can replicate it. All of the 2D and 3D CAD files have been made available under the GPLv3 license, and if you’re in the mood for a little light reading, there’s a nearly 370 page guidebook you can download that covers building and launching the rocket.
Now of course we’re still talking about literal rocket science here, so while we don’t doubt a sufficiently motivated individual could put one of these together on their own, you’ll probably want to gather up a couple friends and have a well-stocked makerspace to operate out of. All told, [Half Cat] estimates you should be able to build a Mojave Sphinx for less than $2,000 USD, but that assumes everything is done in-house and you don’t contract out any of the machining.
Although the designation ‘Air Force One’ is now commonly known to refer to the airplane used by the President of the United States, it wasn’t until Eisenhower that the US President would make significant use of a dedicated airplane. He would have a Lockheed VC-121A kitted out to act as his office as commander-in-chief. Called the Columbine II after the Colorado columbine flower, it served a crucial role during the Korean War and would result the coining of the ‘Air Force One’ designation following a near-disaster in 1954.
This involved a mix-up between Eastern Air Lines 8610 and Air Force 8610 (the VC-121A). After the Columbine II was replaced with a VC-121E model (Columbine III), the Columbine II was mistakenly sold to a private owner, and got pretty close to being scrapped.
In 2016, the plane made a “somewhat scary and extremely precarious” 2,000-plus-mile journey to Bridgewater, Virginia, to undergo a complete restoration. (Credit: Dynamic Aviation)
Although nobody is really sure how this mistake happened, it resulted in the private owner stripping the airplane for parts to keep other Lockheed C-121s and compatible airplanes flying. Shortly before scrapping the airplane, he received a call from the Smithsonian Institution, informing him that this particular airplane was Eisenhower’s first presidential airplane and the first ever Air Force One. This led to him instead fixing up the airplane and trying to sell it off. Ultimately the CEO of the airplane maintenance company Dynamic Aviation, [Karl D. Stoltzfus] bought the partially restored airplane after it had spent another few years baking in the unrelenting sun.
Although in a sorry state at this point, [Stoltzfus] put a team led by mechanic [Brian Miklos] to work who got the airplane in a flying condition by 2016 after a year of work, so that they could fly the airplane over to Dynamic Aviation facilities for a complete restoration. At this point the ‘nuts and bolts’ restoration is mostly complete after a lot of improvisation and manufacturing of parts for the 80 year old airplane, with restoration of the Eisenhower-era interior and exterior now in progress. This should take another few years and another $12 million or so, but would result in a fully restored and flight-worthy Columbine II, exactly as it would have looked in 1953, plus a few modern-day safety upgrades.
Although [Stoltzfus] recently passed away unexpectedly before being able to see the final result, his legacy will live on in the restored airplane, which will after so many years be able to meet up again with the Columbine III, which is on display at the National Museum of the USAF.
Who among us hasn’t at some point thought of building a little vehicle, and better still, a little off-road vehicle for a few high-octane rough-terrain adventures. [Made in Poland] has, and there he is in a new video with a little off-road buggy.
The video which we’ve paced below the break is quite long, and it’s one of those restful metalworking films in which we see the finished project take shape bit by bit. In this case the buggy has a tubular spaceframe, with front suspension taken from a scrap quad and a home-made solid rear axle. For power there’s a 500cc Suzuki two-cylinder motorcycle engine, with a very short chain drive from its gearbox to that axle. The controls are conventional up to a point, though we’d have probably gone for motorcycle style handlebars with a foot shift rather than the hand-grip shift.
The final machine is a pocket drift monster, and one we’d certainly like to have a play with. We’d prefer some roll-over protection and we wonder whether the handling might be improved were the engine sprung rather than being part of a huge swing-arm, but it doesn’t appear to interfere with the fun. If you fancy a go yourself it’s surprisingly affordable to make a small vehicle, just build a Hacky Racer.
Here in the United States, we’re lagging behind the rest of the world when it comes to shiny new passenger rail, despite being leaders in previous centuries. The Federal Railroad Administration (FRA) has just released a story map of how the US could close the gap (a little).
The Corridor Identification and Development (CID) Program is a way for FRA to provide both funding and technical assistance as corridor sponsors (mostly state Departments of Transportation) evaluate either new intercity service or expansion of existing services. While it isn’t a guarantee of anything, it is a step in the right direction to rebuilding passenger rail capacity in the US.
Some cities would be getting rail service back for the first time in decades, and perhaps even more exciting is that several of the routes being studied are for high speed rail “primarily or solely on new trackage.” As any railfan can tell you, vintage rails aren’t the best for trains going fast (sorry, Acela). With recent polling showing strong public support for the build out of high speed rail, it’s an exciting time for those who prefer to travel by rail.
We don’t think you’ll be able to ride a gyro monorail, nuclear-powered, or jet train on these proposed routes, but we do hope that Amtrak and FRA are looking to the state-of-the-art when it comes to those high speed alignments. While you’re eagerly awaiting new passenger service, might we recommend this field guide to what all those different freight cars going by are for here in North America?
Subway cars have a tough life. Moving people through a city efficiently underground every day and night takes a toll on the hardware. To keep things running efficiently, NYC rebuilds its cars every six years.
The enormous job of refurbing a subway car back to factory spec happens in one of two yards, either in Brooklyn or Manhattan. The cars are pulled off their 16,000 lb trucks, and treated to an overhaul of their “doors, windows, signage, seats, floor tiles and HVAC.” The trucks are inspected and wheels can be reground to true at the six year mark; they get all new wheels every 12.
Once everything is repaired, the shiny and like-new components are inspected and reassembled to go back out on the line. While it’s no small job, the overhaul shops can process over 1,000 cars in a year to keep things running smoothly. Before the overhaul program was introduced in the 1980s, NYC subway cars typically experienced failures every 16,000 miles, but between the scheduled maintenance and other advances that number has soared to an average failure rate every 140,000 miles.
Fiddle around with cars long enough and you’ll realize two things: first, anything beyond the simplest repairs will probably require some kind of specialized tool, and second, those tools can be prohibitively expensive. That doesn’t mean you’re out of luck, though, especially if you’ve got scrap galore and a DIY spirit, as this junk bin fuel injector test stand ably demonstrates.
[Desert Rat Racer]’s test rig is designed to support four injectors at once and to test them under conditions as close as possible to what they’ll experience when installed. To that end, [Rat] mounted a junk intake manifold to a stand made from scrap wood and metal found by the side of the road. A pickle jar serves as a reservoir for the test fluid — he wisely used mineral spirits as a safer substitute for gasoline — and a scrap electric fuel pump pressurizes a junk fuel rail, which distributes fuel to the injectors under test.
For testing, the injectors are wired up to an electric injector tester, which is one of the few off-the-shelf components in the build. The fuel pump and injectors are powered by the 12 volt rail of a scrapped PC power supply. Just being able to watch the spray pattern is often enough to find a faulty injector, but in case a more quantitative test is indicated, each injector is positioned over a cheap glass cylinder to catch the test fluid, and scraps of a tape measure are used to measure the depth of the collected fluid. No fancy — and expensive — graduated cylinders required.
While we truly respect the hackiness of [Desert Rat Racer]’s build, the concept of avoiding buying tactical tools is foreign to us. We understand the logic of not dropping a ton on a single-use tool, but where’s the fancy blow-molded plastic case?
