[Ben Gravy] isn’t your average pro surfer. For one thing, he lives in New Jersey instead of someplace like Hawaii or Australia, and for another he became famous not for riding the largest waves but rather for riding the weirdest ones. He’s a novelty wave hunter, but some days even the obscure surf spots aren’t breaking. For that, he decided to build a surfboard that doesn’t need waves. (Video, embedded below the break.)
The surfboard that [Ben] used for this project isn’t typical either. It’s made out of foam without any fiberglass, which makes the board less expensive than a traditional surfboard. The propulsion was handled by an electric trolling motor and was hooked up to a deep cycle battery mounted in the center of the board in a waterproof box. The first prototype ended up sinking though, as most surfboards can’t support the weight of a single person on their own without waves even without all the equipment that he bolted to it.
After some reworking, [Ben] was able to realize his dream of riding a surfboard without any waves. It’s not fast, but the amount of excitement that he had proves that it works and could fool most of us. This hack has everything, too: a first prototype that didn’t work exactly right and was fixed with duct tape, electricity used in a semi-dangerous way, and solving a problem we didn’t know we had. We hope he builds a second, faster one as well.
Bikes are a great way to get around. They’re cheap compared to cars and can be faster through city traffic, and you can get some exercise at the same time. The one downside to them is that the storage capacity is often extremely limited. Your choices are various bags strapped to the bike (or yourself), a trailer, or perhaps this bicycle side car made from a beer keg.
Sidecars are traditionally the realm of motorcycles, not bicycles, but this particular bike isn’t without a few tricks. It has an electric motor to help assist the rider when pedaling. With this platform [Laura Kampf] has a lot of potential. She got to work cutting the beer keg to act as the actual side car, making a hinged door to cover the opening. From there, she fabricated a custom mount for the side car that has a custom hinge, allowing the side car to stay on the road when the bike leans for corners.
For those unfamiliar, [Laura] is a master welder with a shop located in Germany. We’ve seen some of her work here before, and she also just released a video showing off all of her projects for the last year. If you’re an aspiring welder, or just like watching a master show off her craft, be sure to check those out or go straight to the video below.
If you happen to live near Phoenix, Arizona, have a spare US$10,000 or so kicking around, and have always fancied your own true-to-life commercial flight simulator, today is your lucky day. With just over a week to go on the auction, you can bid on a used flight simulator for a Bombardier CRJ200 regional jet airliner.
The CRJ200 jet was produced between 1991 and 2006, first being introduced in 1992 by Lufthansa. It’s a twin-engine design, with about 50 seats for passengers. With a length of more than 26 meters, 12,500 km (41000ft) ceiling, 785 km/h (487mph) cruising speed and a range of around 3,000 km (1864 mi) (depending on the configuration), it offers plenty of opportunities for the aspiring (hobbyist) pilot.
The auction stands at the time of writing at $4,400 offered and lasts until Monday, January the 28th. Local pick-up is expected, but the FAA-certified simulator comes complete with all of the manuals and the guarantee that it was 100% working before it was disassembled to ready it for auction. Just make sure that you have somewhere to put it before putting in that bid, and you could be the owner of a rig that would leave some of the best we’ve seen so far behind in the dust.
When Charles “Chuck” Yeager reached a speed of Mach 1.06 while flying the Bell X-1 Glamorous Glennis in 1947, he became the first man to fly faster than the speed of sound in controlled level flight. Specifying that he reached supersonic speed “in controlled level flight” might seem superfluous, but it’s actually a very important distinction. There had been several unconfirmed claims that aircraft had hit or even exceeded Mach 1 during the Second World War, but it had always been during a steep dive and generally resulted in the loss of the aircraft and its pilot. Yeager’s accomplishment wasn’t just going faster than sound, but doing it in a controlled and sustained flight that ended with a safe landing.
Chuck Yeager and his Bell X-1
In that way, the current status of hypersonic flight is not entirely unlike that of supersonic flight prior to 1947. We have missiles which travel at or above Mach 5, the start of the hypersonic regime, and spacecraft returning from orbit such as the Space Shuttle can attain speeds as high as Mach 25 while diving through the atmosphere. But neither example meets that same requirement of “controlled level flight” that Yeager achieved 72 years ago. Until a vehicle can accelerate up to Mach 5, sustain that speed for a useful period of time, and then land intact (with or without a human occupant), we can’t say that we’ve truly mastered hypersonic flight.
So why, nearly a century after we broke the sound barrier, are we still without practical hypersonic aircraft? One of the biggest issues historically has been the material the vehicle is made out of. The Lockheed SR-71 “Blackbird” struggled with the intense heat generated by flying at Mach 3, which ultimately required it to be constructed from an expensive and temperamental combination of titanium and polymer composites. A craft which flies at Mach 5 or beyond is subjected to even harsher conditions, and it has taken decades for material science to rise to the challenge.
With modern composites and the benefit of advanced computer simulations, we’re closing in on solving the physical aspects of surviving sustained hypersonic flight. With the recent announcement that Russia has put their Avangard hypersonic glider into production, small scale vehicles traveling at high Mach numbers for extended periods of time are now a reality. Saying it’s a solved problem isn’t quite accurate; the American hypersonic glider program has been plagued with issues related to the vehicle coming apart under the stress of Mach 20 flight, which heats the craft’s surface to temperatures in excess of 1,900 C (~3,500 F). But we’re getting closer, and it’s no longer the insurmountable problem it seemed a few decades ago.
Today, the biggest remaining challenge is propelling a hypersonic vehicle in level flight for a useful period of time. The most promising solution is the scramjet, an engine that relies on the speed of the vehicle itself to compress incoming air for combustion. They’re mechanically very simple, and the physics behind it have been known since about the time Yeager was climbing into the cockpit of the X-1. Unfortunately the road towards constructing, much less testing, a full scale hypersonic scramjet aircraft has been a long and hard one.
The year is 1894. You are designing a train system for a large city. Your boss informs you that the mayor’s office wants assurances that trains can’t have wrecks. The system will start small, but it is going to get big and complex over time with tracks crossing and switching. Remember, it is 1894, so computing and wireless tech are barely science fiction at this point. The answer — at least for the New York City subway system — is a clever system of signals and interlocks that make great use of the technology of the day. Bernard S. Greenberg does a great job of describing the system in great detail.
The subway began operation in 1904, well over 30 years since the above-ground trains began running. A clever system of signals and the tracks themselves worked together with some mechanical devices to make the subway very safe. Even if you tried to run two trains together, the safety systems would prevent it.
On the face of it, the system is very simple. There are lights that show red, yellow, and green. If you drive, you know what these mean. But what’s really interesting is the scheme used at the time to make them light.
Clamped or bolted to the stern of the boat, outboard motors offer a very easy and (relatively) economical way of powering small craft. The vast majority of these outboards are gasoline powered, with electric models generally limited to so-called “trolling motors” which are often used to move slowly and quietly during fishing. That might be fine for most people, but not [Olly Epsom].
An engineer focusing on renewable energy by profession, [Olly] wanted to equip his small inflatable dinghy with a suitably powerful “green” propulsion system. Deciding nothing on the market quite met his requirements, especially for what manufacturers were charging, he decided to convert an old gas outboard to electric. Not only did he manage to do it for less money than a turn-key system would have cost, but he ended up with a system specifically geared to his exact requirements. Something he says will come in handy if he ever gets around to converting the dinghy to remote control so he can use it as a wildlife photography platform.
Put simply, an outboard motor consists of a gasoline engine with a vertical shaft that’s coupled to a right-angle gearbox with a propeller on the end. Beyond that they’re a fairly “dumb” piece of gear, so replacing the engine on top with something else should be (at least in theory) a pretty simple job. Especially on the small older model that [Olly] decided to use as a donor unit. The 1974 Johnson 2 HP motor didn’t have any tricky electronics in it to contend with; the thing didn’t even have a clutch.
Once [Olly] had removed the old gas engine from the top of the outboard, he designed an adapter plate in OnShape and had it cut out of aluminum so he could mount a beefy 1 kW 48 V brushless electric motor in its place. Connecting the new electric motor to the carcass of the outboard actually ended up being simpler than putting the original motor on, as this time around he didn’t need to reconnect the cooling pumps which would usually pull water from down by the propeller and recirculate it through the engine.
While the mechanical aspects of this project are certainly cool, we’re especially interested in the control system for this newly electric outboard. It uses a 3.2 inch Nextion color touch screen and Arduino Nano to provide a very slick looking digital “dashboard” which can convey motor status and other information at a glance. Unfortunately, [Olly] says the details on that part of the project will be saved for a future post, leaving us with only a single picture of the system’s interface for us to drool over until then.
Low-slung body style. Four-wheel drive. All electric drivetrain. Turns on a dime. Neck-snapping acceleration. Leather seating surface. Is it the latest offering from Tesla? Nope; it’s a drill-powered electric utility vehicle, and it looks like a blast to drive.
Surprisingly, this isn’t a just-for-kicks kind of build. There’s actually a practical reason for the low form factor and long range of [Axel Borg]’s little vehicle. We’ll leave the back story to the second video below, but suffice it to say that this will be a smaller version of the crawler NASA used to roll rockets out to the launch pad, used instead to transport his insanely dangerous looking manned-multicopter. The running gear on this vehicle is the interesting bit: four hefty electric drills, one for each of the mobility cart wheels. The drills are powered by a large series-connected battery pack putting out 260V at full charge. The universal motors of the drills are fine with DC, and the speed of each is controlled via the PWM signals from a pair of cordless drills. The first video below shows [Axel] putting it through its paces; he didn’t hold back at all, but the vehicle kept coming back for more.
We know this cart is in service to another project, but we’d have a hard time concentrating on anything if we had the potential for that much fun sitting in the shop. Still, we hope that multirotor gets a good test flight soon, and that all goes well with it.
