Here's a trio of curated content from around the Web, showcasing videos of homebrew efforts to construct small jet engines. Two are made out of repurposed junk, while our cutting-edge first example is a student engine created using a 3D printer.
One would think such an engine, built by students in a Jet Engine Manufacturing Class at the University of Virginia's Mechanical and Aerospace Engineering Department, would melt. However, as Professor David Sheffler notes in this YouTube video, it's a demo engine. "We're using compressed air, instead of having an actual flame in there that would burn up our parts," he says.
The model is a dual-concentric turbofan. It's got a high-pressure compressor spun by a high-pressure turbine, and a low-pressure turbine spinning the fan up front.
Under-$100 engine
Our next example is an oldie but goodie, in multiple senses of the phrase. It was designed by Dave Chovanak in 1965 when he was a student at Nevada Southern University. In the YouTube video, he says it was made with $85 worth of junk parts, including components drawn from a flower vase and Hoover vacuum cleaner, and has bearings made out of copper plumbing fittings.
The engine, called "The Rebel," is said to weigh 5 lbs. and deliver 8 lbs. of thrust. It spins at 35,000 rpm at maximum throttle. Unfortunately, the video doesn't show the completed engine or its operation.
The finished engine can be seen in Chovanak's Photobucket stream (click on the image below):
Test-stand turbo
Our final video is a rudimentary jet engine constructed out of a turbo off of a Continental TSIO-520. The latter is a conventional piston aircraft engine from the early 1960s, made by Teledyne.
It's mounted on a test stand and, when lit, is satisfyingly noisy. However, it doesn't seem to deliver a whole heck of a lot of thrust. This one was uploaded to YouTube by kyleandellenb, with editing by Jonathan Santhouse.
Editor's note
Gadget Freak Jr. is an effort to broaden the range of projects we showcase by scouring the Web universe for interesting and relevant material. We'd like your opinions on this first offering, and we also welcome your contributions. Please write to me at alex.wolfe@ubm.com.
Credits: A complete story on the U. Va. student jet engine, written by Steve Rousseau, first appeared in July on Popular Mechanics. Our embedded video was obtained from YouTube, to which it was uploaded by Boricualn1707.
The info on the Dave Chovanak $85 "Rebel" engine was drawn from the video and the description posted on Batygoldfly's YouTube channel. The picture of Chovanak holding the engine comes from Dave's Photobucket stream.
I am glad to see you have rethought your position. The opposite of wreckless is not meek, but the opposite of cavelier is thoughtful. Your cavelier attitude toward the safety of coworkers that was presented in your first post has been replaced by a more thoughtful response. I just hope the attitude shift was real and not contrived when you realized how silly the first post sounded.
Hey Ivan... I was hoping that someone who built one of these 'turbo-jets' would post. I've watched a few hours worth of the videos that the backyard mechanics have of these up on YouTube... They look like a fun toy to experiment with.
And going with an old auto turbocharger seems relatively safe.
As an electrical engineer, my peers raise their eyebrows when they learn of my interest in jet engines. I love reading about, and sometimes experimenting with, turbines and pulse jets, and an occasional rocket (OK, so it's not an air-breathing jet engine).
I enjoyed the construction article and I'd like to add to the commentaries an experience I had with a pulse jet and the useful lessons I learned. Please see the following link in Design News magazine:
I remember so long ago reading in Popular Mechanics how a backyard mechanic built a tiny jet for his glider so he wouldn't have to use a tow plane - and apparently it worked! So as a kid I read through all the jet engine articles in the encyclopedia and everything they had at the library.
Jets deliver decent fuel economy and incredible power density but they are the opposite of "tractable" in that they don't really make a lot of (low speed) torque and they don't handle changes in power output very well. However, I always figured a small jet running an appropriately geared generator would make an admirable hybrid powerplant for a car.
Then again diesel-electric locomotives were the original hybrid, and I've never heard of a jet-electric locomotive, so maybe it isn't such a good combo in reality.
Actually jet engines have terrible fuel consumption. As do turbine powered shafts as in turbine powered cars. Their big advantage is power/weight.
It's only very recently that high bypass turbofans on airliners became comparable to other engines on a distance/payload/fuel basis. And this requires operation at very high speeds & altitudes.
There was a rash of demonstration turbine cars in the 60's but then came the oil crisis ...
Interesting - according to whoever contributed to Wikipedia, the "micro turbine" is recognized as a promising technology for powering future hybrid electric vehicles. Efficiency of modern versions approaches that of reciprocating engines. Hotter exhaust is also more useful for cabin heating/cooling. Range Rover is apparently currently working on another turbine powered car (a turbine electric hybrid) as a follow up to their failed 1960 Rover turbine prototype that, lacking an electric intermediary stage, had terrible throttle response. So interesting! Wow, maybe batman was right after all, maybe jet cars will finally become reality. If the turbine has just 1 moving part like the electric intermediary, maintenance should really be a thing of the past.
I don't know how viable a turbine would be for a car. Look at the Abrams tank, which needs 7 gallons of jet fuel just to light the engine. It's got a 500 gallon tank but I believe Abrams tanks in battle need a hefty supply line to support them, because they have to be refueled every four hours.
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