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.
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):
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.
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 firstname.lastname@example.org.
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 think you have just perfectly illustrated Martin's point. Even with all the testing and safe practices utilized on the space program accidents still happened and lives were lost. To assume those were the only lives that would have been lost if all of the precautions had not been attended to is just plain wrongheaded. Why do you think the missions were suspended after each of those tragdies? Studies were conducted and changes made so those would be one time occurances.
As for as your "We are all going to buy the farm" attitude: I hope you have the decency to tell all of your coworkers of your feelings before you engage them in any activity that could be hazardous. If you continue to work in that manner, you will not have to worry about that nursing home. My hope is that you do not take anyone along with you. Stupid may be a harsh word, but it will do until a better one comes along.
I think that the term, "stupid" is a little harsh. People place way-too-much emphasis on safety to the point that it impedes R & D efforts. True, the students, and faculty need to take precautions, but if we buy-into your philosophy, we wouldn't have had a great run with the Space Shuttle. We lost two ( 2 ) crews, but while tragic to be certain, you didn't see anyone back-away from future missions, either. Life's dangerous, period, and end, and we're all going to, "buy the farm" sooner, or later. I'm not seeing a down-side to dying while doing something that you're passionate about - it sure-as-Hell beats dying while taking a dump in the Nursing Home restroom.
A couple years back when I had some downtime between jobs my friend Asim and I built a nifty jet engine using a turbocharger. The interesting part was constructing the combustion chamber. I designed it and created the CAD drawings and had a local machinist cut the metal from scraps I got at a boeing scrap yard in Kent WA. teh compbustion chamber was about 20 inches long and made of some Inconel pipe I found.
It worked well enough but it turns out to create any kind of useful thrust the engine has to move a lot of air. The turbochargers from cars and big trucks have very heavy casings to resist catastrophic failures so I was not too worried about the high speed compressor rotor coming apart.
The idea we were working on was to create a Solar powered engine to drive a PMG directly coupled to the turbine. Unfortunately I had to go back to work but it was certainly a fun project. I wish I had the pictures and the thermal analysis software I wrote for it.
Unbelievably stupid; When an overspeed sends 2 halves of a centrifugal compressor in opposite directions, you can get two students at once. Then, the unloaded turbine can overspeed and blow. A tour of a real test cell with pictures of the torn up concrete walls looking like machine gun pits and ripped up casings should be coming from the professors. Even the brilliant designers and builders at Pratt, Rolls or GE keep concrete or 20 pains of glass between themselves and the new product........
It should also be noted that the use of small jet engines has become quite common in the model airplane field. Well, quite common in a somewhat limited sense! Model jet turbines with impressive performance are readily available although the costs are (at least to this penny pinching engineer) pretty high (somewhere in the $2,000 and up range) and there are a number of model airplanes available to house these engines.
The newer ones are incorporating an impressive amount of 'smarts' (i.e. uP controllers) for much greater ease in starting and running. The engines are also incorporating trust control including vectored thrust control (i.e. the engine's output can be slewed from the normal axis to permit some amazing variations in the aircraft's flight path).
The performance of these jet equipped models is truly impressive .... and loud!
Love this treatment. Very cool to see the juxtaposition of the jet engine created in the university setting, all buttoned up and produced (unbelievably so) with a 3D printer compared to the guy in what looks to be his basement with the 40-year plus crinkled up design plans. Either way, great stuff and a perfect way to showcase the back-room innovations happening every day.
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