propellor

4 Articles

This Electric Outboard Conversion Makes For A Quiet Day On The Water

November 29, 2022 by 21 Comments

Nothing beats a day on the lake in a little boat with an outboard motor putt-putting along behind you. It’s great fun, if perhaps a little noisy with all that putting going on. And maybe that oily sheen on the water in your wake is not so nice. it could be that the fish are a little annoyed with your putting, too. Come to think of it, outboard motors are a bit of a problem.

Fortunately there’s a better way, like converting an old outboard motor to electric. It comes to us by way of [Anton], who happened upon the perfect donor platform — a 5-hp outboard by Crescent, sporting a glorious 1970s color scheme and a motor housing shell perfect for modding. He started by ripping the old engine and drivetrain out of the housing to make room for the BLDC motor and its driver. The motor was a project in itself; [Anton] rewound the original stator with much thicker wire and changed the coil configuration to milk as much torque as possible out of it. What started as a 180-kv motor ended up at 77 kv with much more copper and new Hall sensors for the controller. He also put a ton of effort into waterproofing the motor with epoxy resin. With a 3D-printed prop and a streamlined fairing, the new motor looks quite at home on the outboard. In fact, the whole thing barely looks customized at all — the speed control is even right on the tiller where you’d expect it.

The video below shows the build and a test run, plus an analysis of the problems encountered, chief of which is water intrusion. But as [Anton] rightly points out, that’s easily solved by reusing the original driveshaft and mounting the motor above the waterline, like this. Still, we like the look of this, and the idea of knocking around on the water nearly silently seems wonderful.

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da Vinci-like quadcopter

Renaissance-Style Drone Would Make Da Vinci Proud Four Times Over

February 1, 2022 by 7 Comments

For as much of a genius as Leonardo da Vinci obviously was, modern eyes looking upon his notebooks from the 1400s tend to see his designs as somewhat quaint. After all, his concept of a vehicle armored with wood would probably only have survived the archers and pikemen of a Renaissance battlefield, and his curious helicopter driven by an Archimedes screw would certainly never fly, right?

Don’t tell that to [Austin Prete] and his team from the University of Maryland, who’ve built a da Vinci-style quadcopter that actually flies. Called the “Crimson Spin”, the quad is based on a standard airframe and electronics. Details are sparse — the group just presented the work at a vertical flight conference — but it appears the usual plastic props are replaced with lightweight screws made from wire and some sort of transparent plastic membrane. Opposing pairs of screws have the opposite handedness, which gives the quad yaw control. There’s a video embedded in the link above that shows the quad being tested both indoors and out, and performing surprisingly well. We’d imagine that Crimson Spin might not do so well on a windy day, given the large wind cross-section those screws present, but the fact it got off the ground at all is cool enough. It kind of makes you wonder where we’d be today if da Vinci had access to BLDCs.

For as fanciful as da Vinci’s designs can be, we’ve seen a fair number of attempts to recreate them in modern materials. His cryptex is a perennial favorite for hackers, and his bizarre piano-esque “viola organista” has been attempted at least once.

Thanks to [Peter Ryseck] for this tip.

Repaired Manned Multicopter Flies Without Horrifying Crash

July 28, 2016 by 81 Comments

[amazingdiyprojects] has been making lots of test flights in his crazy eight propeller gasoline powered danger bucket.

We last covered the project when he had, unfortunately, wrecked the thing in a remote-controlled test flight.  He later discovered that the motor’s crankshaft bearings had, well, exploded. The resulting shrapnel destroyed the motor and crashed the drone. He described this failure mode as “concerning”.

Also concerning is the act of stepping into the seat once all the propellers are started up. He tags this as “watch your step or die”. Regardless, he also describes flying in the thing as so incredibly fun that it’s hard to stay out of it; like a mechanical drug. It explains why his channel has been lately dominated by videos of him testing the multicopter. Those videos are found after the break.

The device drinks 0.65-0.7 liters per minute of gasoline, and he’s been going through reserves working out all the bugs. This means everything from just figuring out how to fly it to discovering that the dust from the ground effect tends to clog up the air filters; which causes them to run lean, subsequently burning up sparkplugs. Dangerous, but cool.

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VertiGo Robot Drives Up Walls

July 24, 2016 by 19 Comments

This collaboration between ETH and the Disney empire’s research arm is a ultra-light robot that can roll across horizontal surfaces and also transition and climb walls.

The robot has four wheels with one steerable set, but its secret sauce is the two propellers gimbaled on its back. Using these propellers it can move itself across the ground, but also, when approaching a wall, provide enough thrust to overcome the gravity vector.

Naturally, the lighter the robot, the less force will be needed to keep it on the wall. That’s why the frame is made from carbon fiber corrugated sandwich panels. The motors, batteries, and controllers are all also light and small.

We liked how the robot was, apparently, using its propellers to provide additional stability even while on the ground. There is a video after the break, and more information can also be found on the Disney Research webpage.

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