Producing Ozone at 3500 RPM


Motors are fun, and high voltage even more so. We’re guessing that’s what went through [brazilero2008]’s mind when he put together an electrostatic motor using upcycled parts he found lying around.

The electrostatic rotor works by connecting a very high voltage, low current power supply – in this case an industrial air ionizer – to a set or rotors surrounding a plastic rotor. The hot electrodes spray electrons onto the rotor, which are picked up by the ground electrodes. If the system doesn’t arc too much, you have yourself a plastic rotor that spins very, very fast.

[brazilero]’s device is made out of an aluminum turkey pan, a few acrylic tubes, and a few cardboard disks; all stuff you can find in a well-stocked trash can. After completing the device, it was taken apart and finished and screwed onto a beautiful painted jewelry box. Very cool for something you can make out of trash, and dangerous enough to be very interesting.

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3D Printed Cutaway Jet Engine Sounds Great

Thanks to the wonders of 3D printing, you can now have a 3D printed a jet engine of your very own. Unlike jet engines we’ve seen before, this one comes with no chance of the operator getting burned to a crisp. [Gerry] is a self-proclaimed “broken down motor mechanic” from New Zealand. He’s designed a rather awesome jet engine in 3D Software, and printed it on his UP Plus printer. The engine itself is a cutaway model of a high-bypass turbofan engine. While we’re not sure which make and model of jet engine this cutaway represents, we’re still very impressed.

This isn’t just a static display model – the engine will actually spin up with the help of compressed air.  Separate start and run tubes send air to the turbine and main fain respectively. It even has that distinctive turbofan “buzz saw” sound. While this model is relatively safe, [Gerry] does warn to keep the pressure down, or it could come apart. To that end we’d recommend adding a regulator before the quick disconnect.

The Thingiverse project is a bit light on instructions.  However this situation is remedied by [hacksaw], who posted a pictorial and build log up on pp3d. [Hacksaw] did run into a few problems with the build, but nothing a little bit of superglue couldn’t fix. It may have fewer moving parts, but this definitely puts our old Visible V8 Engine kit to shame.

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An homemade 48cc V8 engine with injection

A few months ago we mentioned [Keith]’s first project in the works, a 1/4 scale V8 engine. Today, we are amazed to see that his engine is finished and running really smoothly. What is even more impressive is that the entire project has been completed on manual mills and lathes. The thread on the Home Model Engine Machinist forum contains his build log in which he details how all the different parts were made. The engine has an electric starter, uses a fuel injection system and [Keith] even made his own injection molds for several plastic parts. The ECU is based on the Megasquirt-II, we guess it must have taken [Keith] many tries before correctly setting its parameters. A video of the engine in action can be viewed after the break.

You can find our previous coverage of this project as well as other miniature engines on this feature from last April.

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(Please Don’t) Build a Jet Engine from a Toilet Paper Holder

Turbo charger Jet Engines have long been considered one of the holy grails of backyard engineering. This is with good reason – they’re hard to build, and even harder to run. Many a turbo has met an untimely end from a hot start or oil starvation. [Colin Furze] however, makes it look easy. [Colin] is a proponent of crazy hacks – we’ve featured him before for his land speed record holding baby carriage, and his pulse jet powered tea kettle.

In his latest video set, [Colin] takes a toilet brush holder, a toilet paper roll holder, a few plumbing fittings, and of course a small turbocharger from the scrap yard. Somehow he converts all of this into a working jet engine. The notable thing here is that there is no welding. Some of the joints are held together with nothing more than duct tape.

Calling this a working jet engine is not really an overstatement. As every backyard jet jockey knows, the first goal of DIY jets (aside from not hurting yourself) is self-sustaining. Turbines are spun up with air hoses, vacuums, or leaf blowers. The trick is to turn the fuel on, remove the air source, and have the turbine continue spinning under its own power. Once this happens, your engine is performing the same “Suck, Squeeze, Bang, Blow” combustion process an F-18 or a 747 uses.

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Restoring an Industrial Tractor


[Nickolas] dropped us a tip about a Youtube channel where [stevewatr] documents the restoration of an Oliver 770 tractor through no less than 133 videos. These videos span the last year, starting with finding the tractor in fairly dense undergrowth. He spends quite a bit of time troubleshooting the engine, explaining his thought process, and showing all of the steps he takes to get the tractor running reliably again. He also delves into fixes for the electrical and hydraulic systems.

In his tip, [Nickolas] said he just couldn’t stop watching, and we agree, this is really a fascinating series. One of the things we love about these videos is that [stevewatr] doesn’t filter out his mistakes. That means we get to see his failures and successes… Everything from how jump starting wasn’t possible with a small jumper wire, to getting the engine to start cold without a primer. That’s the beauty of our fail-of-the-week posts. Absorb it all, and you’ll be prepared when you run into related problems yourself.

[stevewatr’s] last video doesn’t show a completed tractor, so we look forward to seeing what happens as the project progresses. Even if you aren’t interested in having a tractor of your own, you can certainly use some of this information while building your own personal mech. Give it a try!

Electrified Yard Equipment Hauls Grass


[AmpEater] spent the summer converting yard equipment from internal combustion to electric power. The conversions run from a relatively tame Wheel Horse, to an insane Cub Cadet. The Wheel Horse lost its Kohler engine in favor of a hydraulic pump motor from a crown forklift. 48 volt power is supplied by MK lead acid gel cells. An Alltrax 300 amp controller keeps this horse reigned in.

On his Reddit thread, [AmpEater] says he is especially proud of his Cub Cadet zero turn ride on mower. For those who aren’t up on lawn implement terminology, a “zero turn” means a mower with zero turning radius. Zero turn mowers use two large wheels and tank style steering to turn within their own radius. We bet this style mower would also make a pretty good robot conversion, however [AmpEater’s] zero turn is still setup for cutting the grass.

After pulling the V-twin motor the 48 volt Motenergy ME-1004 was put in place. Batteries are 3 x Enerdel 48V 33 amp hour lithium ion packs. The packs are wired in series to provide 144V nominal. Right about here is where our brain started to melt. A 48V motor on 144V has to mean magic smoke, right? This is where the motor controller magic comes in.

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DIY 250 lb thrust Liquid Oxygen/Kerosene Rocket

Robert’s Rocket Project has been going on for a long time. It has been around so long that you can go all the way back to posts from 2001, where he talks about getting his first digital camera! The site is dedicated to his pursuit of liquid fueled rocket engine building. It’s a great project log and he has finally come to the point where he will be testing his first flight vehicle soon.

His latest project is a 250lbf regeneratively cooled engine. It uses kerosene as the fuel, and liquid oxygen as the oxidizer. The neat thing is he utilizes the temperature change of the liquid oxygen expanding to cool the chamber and nozzle before being burned. This allows for a very efficient and powerful combustion of the fuel. He has some videos of testing it on his site, we just wonder why he doesn’t host them on YouTube or something…

Anyhow, there’s more than enough info on his site to try and recreate some of his experiments, but perhaps you should start here instead: How to Design, Build and Test Small Liquid-Fuel Rocket Engines.

[Thanks Ray!]