two-stroke

5 Articles

This Is The Bike You Wanted Your Dad To Make You When You Were Eight Years Old!

November 16, 2019 by 22 Comments

The ever-resourceful [Turbo Conquering Mega Eagle] has an excellent excuse for starting on projects, he’s building them for his kids and making videos. We’re not so sure his little motorcycle wasn’t built because Dad also wants to have a go though, because it seems he had quite a lot of fun testing it.

The build starts with a Chinese petrol conversion kit for a bicycle. There’s a little twofour-stroke motor and a basic chain drive to a large sprocket intended to fit on the opposite side of a bicycle wheel to the pedal sprocket. He uses a pair of pneumatic wheelbarrow wheels for which he makes a new bush and to which he welds the sprocket. These go into a fairly simple hardtail frame for which he makes a padded motorcycle seat, and from then on he’s ready to go.

The result is a rather cool little non-road-legal motorcycle that we suspect most readers will have a hankering to own. We’re not so sure about its seeming lack of brakes though. Judge for yourself, the video is below the break.

This isn’t the first home made small bike we’ve brought you, though it’s a lot safer than the first one.

Continue reading “This Is The Bike You Wanted Your Dad To Make You When You Were Eight Years Old!” →

Adopting An Orphaned Ultralight

November 29, 2018 by 69 Comments

Owning and flying your own small airplane offers a nearly unmatched level of freedom and autonomy. Traveling “as the crow flies” without having to deal with traffic on the ground immediately shrinks your world, and makes possible all sorts of trips and adventures. Unfortunately the crippling downsides of plane ownership (storage and maintenance costs, knowledge that you might die in a fiery crash, etc), keeps most of us planted squarely on terra firma.

But not [ITman496]. His dream of owning an ultralight has recently come true, and he’s decided to share his experience with the world. He’s got a long way to go before he slips the surly bonds of Earth, but there’s no better place to start than the beginning. In a recent blog post he documents the process of getting his new toy home, and details some of the work he plans on doing to get it airworthy.

The plane in question is a Mini-MAX that [ITman496] has determined is not only older than he is, but has never flown. It was built by a retired aircraft mechanic who unfortunately had problems with his heart towards the end of assembly. He wisely decided that he should find a safer way to spend his free time than performing solo flights in an experimental aircraft, so he put the plane up for sale.

After a considerable adventure transporting the plane back home, [ITman496] found it was stored in such good condition that the engine started right up. But that doesn’t mean it’s ready for takeoff by any stretch of the imagination. For his own safety, he’s planning on tearing down the entire plane to make sure everything is in good shape and assembled correctly; so at least he’ll only have himself to blame if anything happens when he’s in the air.

One the plane’s structure is sound, he’ll move on to some much needed engine modifications including a way to adjust the air-fuel mixture from inside the cockpit, improvements to the cooling system, and installation of a exhaust system that’s actually intended for the two-stroke engine he has. When that’s done, [ITman496] is going to move onto the real fun stuff: creating his own “glass cockpit”.

For Hackaday readers who don’t spend their time playing make believe in flight simulators, a “glass cockpit” is a general term for using digital displays rather than analog gauges in a vehicle. [ITman496] has already bought two daylight-readable 10.1″ IPS displays which he plans on driving over HDMI with the Raspberry Pi. No word on what his software setup and sensor array will look like, but we’re eager to hear more as the project progresses.

If you’re not lucky enough to find a mostly-complete kit plane nearby on Craigslist, you could always just make your own airplane out of sheets of foam.

Fail Of The Week: Leaf Blowers Can’t Fly

November 12, 2018 by 31 Comments

Leaf blowers, the main instrument of the suburban Saturday symphony, are one of the most useful nuisances. It doesn’t take much work with a rake to convince even the most noise-averse homeowner to head to the Big Box Store to pick one up to speed lawn chores. Once you do buy one, and feel the thrust produced by these handheld banshees, you might wonder, If I let go of this thing, would it fly? 

[Peter Sripol] had that very thought and set about building a couple of leaf blower powered planes to answer the question. It’s probably not a spoiler alert to report that the answer is no, but the video below is a fun watch anyway. The surprising thing is just how close both planes came to succeeding. The first plane was a stripped-down Ryobi two-stroke leaf blower suspended from a giant wing and tail section that very nearly got off the ground. Version 1.1 gained a retractable electric boost propeller – strictly for take-offs – and lost a lot of excess weight. That plane practically leaped into the air, but alas, servo problems prevented [Peter] from shutting down the electric and flying on Ryobi alone. Even a servo fix couldn’t save the next flight, which cratered right after takeoff. A version 2.0, this time using a brutally modified electric leaf blower, was slightly more airworthy but augured in several times before becoming unflyable.

What can we learn from all this? Not much other than it would take a lot of effort to make a leaf blower fly. We appreciate all of [Peter]’s hard work here, but we think he’s better off concentrating on his beautiful homebrew ultralight instead.

Continue reading “Fail Of The Week: Leaf Blowers Can’t Fly” →

3D-Printed Parts Torture-Tested In Nitro Engine — Briefly

February 22, 2018 by 11 Comments

Additive manufacturing has come a long way in a short time, and the parts you can turn out with some high-end 3D-printers rival machined metal in terms of durability. But consumer-grade technology generally lags the good stuff, so there’s no way you can 3D-print internal combustion engine parts on a run of the mill printer yet, right?

As it turns out, you can at least 3D-print connecting rods, if both the engine and your expectations are scaled appropriately. [JohnnyQ90] loves his miniature nitro engines, which we’ve seen him use to power both a rotary tool and a hand drill before. So taking apart a perfectly good engine and replacing the aluminum connecting rod with a PETG print was a little surprising. The design process was dead easy with such a simple part, and the print seemed like a reasonable facsimile of the original when laid side-by-side. But there were obvious differences, like the press-fit bronze bearings and oil ports in the crank and wrist ends of the original part, not to mention the even thickness along the plastic part instead of the relief along the shaft in the prototype.

Nonetheless, the rod was fitted into an engine with a clear plastic cover that lets us observe the spinning bits right up to the inevitable moment of failure, which you can see in the video below. To us it looks like failing to neck down the shaft of the rod was probably not a great idea, but the main failure mode was the bearings, or lack thereof. Still, we were surprised how long the part lasted, and we can’t help but wonder how a composite connecting rod would perform.

Still in the mood to see how plastic performs in two-stroke engines? Break out the JB Weld.

Continue reading “3D-Printed Parts Torture-Tested In Nitro Engine — Briefly” →

An Open Source Two Stroke Diesel

April 8, 2016 by 42 Comments

With a welder and a bunch of scrap, you can build just about anything that moves. Want a dune buggy? That’s just some tube and a pipe bender. Need a water pump? You might need a grinder. A small tractor? Just find some big knobby tires in a junkyard. Of course, the one thing left out of all these builds is a small motor, preferably one that can run on everything from kerosene to used cooking oil. This is the problem [Shane] is tackling for his entry to the 2016 Hackaday Prize. It’s an Open Source Two-Stroke Diesel Engine that’s easy for anyone to build and has minimal moving parts.

[Shane]’s engine is based on the Junkers Jumo 205 motor, a highly successful aircraft engine first produced in the early 1930s and continued production through World War II. This is a weird engine, with two opposed pistons in one cylinder that come very close to slamming together. It’s a great design for aircraft engines due to it’s lightweight construction. And the simplicity of the system lends itself easily to wartime field maintenance.

The Jumo 205 was a monstrous 12-piston, 6-cylinder engine, but for [Shane]’s first attempt, he’s scaling the design down to a 50cc motor with the intent of scaling the design up to 125cc and 250cc. So far, [Shane] has about 30 hours of simple CAD work behind him and a ton of high-level FEA work ahead of him. Then [Shane] will actually need to build a prototype.

This is actually [Shane]’s second entry to the Hackaday Prize with this idea. Last year, he threw his hat into the ring with the same idea, but building a working diesel power plant is a lot of work. Too much for one man-year, certainly, so we can’t wait to see the progress [Shane] makes this year.

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