Excellent class project! The professor seems a dedicated and enthusiastic man, so you guys are lucky to be guided under such expertise. Well done to all involved in this project!!!!!
When I was in Aerospace College, we had real engines as demos. A couple of Rolls Royce Avons from Hawker Hunters and Vipers from Jet Provosts plus an Adour from a Jaguar still with the Afterburner unit attached. The viper and the Adour were statics but we used to fire up the Avon from time to time. Plus we had a Mk5 jet Provost in the hangar which would be powered up to do gear function tests, dry turbine runs and avionic functions.
tomcatter11 yes, but too bad it cost money to run it and and maintain it, not to mention the space needed, we got alot of jet engines here in USM(malaysian science university).....replicas like these are much much cheaper and almot cost nothing to run it :(
Well that was real nice learning model of how one functions. Was a nice view of the compressor blades and output blades to spin the main intakes. Burn chamber section became a means to spin it all up with a mock up run, All kept to what looks like in a functional means as well! nice work.
10p6 You are completely wrong. The "fan" section produces 80% of the thrust from the engine. The compressor provides the air to be mixed with the fuel to drive the highpressure section... which drives the fan.
obese1konobe guys I hate to be a bummer but this model is simply a replica to demonstrate and learn about how parts are designed/assembled. to have a real feel for what they look like. honestly most of the energy put into the engine (injecting compressed air in this case instead of burning fuel since we're working with plastic) goes to friction from spinning the parts and the thrust created is negligible. that said, in the real version of a design like this one, obese1konobe is right in that the bypass air from the fan produces more thrust than the compressed air on the inside.
obese1konobe As ive been working with PW JT9`s im pretty sure the highpressure section does not drive the fan. It drives the high pressure compressor cause they are on the same spole/shaft, mabey youre talking about something i dont know about? :) if so id like to know :) The fan is driven by the lowpressure turbines, both the lowpressure turbines and highpressure turbines are of course driven by exhausts. True thou is that the fan makes the main thrust for the engine. You do have some reactionpower coming from the core engine as well but the main thrust is from the main fan. If you have ever had youre hand behinde the main fan in a testcell during engine testing you will understand the amount of air that fan moves just at idle, mindblowing actually! Just wanted to clear up the thing about what drives what :) So, you start the enginge by stating the highpressure core/spole/shaft. The exhausts from combining the highcompressor air with JET A1 creats combustion that passses over guidewanes to the highpressure turbine and throu to the lowpressure turbine makeing it rotate to drive the fan. So the fan is on a separete core/spol/shaft than the highpressure spole/shaft. The highpressure core/spole will start the lowpressure core/spole/shaft and you are now runing the engine. Now put some fuel nozzels behind the lowpressure turbinestage and you have a afterburner :D Sorry for bad eng, im a Swede and its been a long time seens i was in school :) Best regards
+10p6 For all those who believe they are giving technical answers, I was referring to the air coming out of the 'Compressed Air Tank' (That big red thing) for the model.
thank you for your criticism. this is an undergraduate class and theres only so much you can really do with it. to your point on seeing how real parts work, we visited multiple manufacturing facilities and machine shops to see how the parts are built and machined. about hands-on, we also used the same machines and tools on our plastic parts to machine them down to .002 inch (if I remember correctly) precision, pretty much the same way commercial machine shops do with their engine parts.
I would hate to be "that guy", but technically way you have is a working model of a turbofan engine, not to be confused with a jet (or turbojet) engine. The difference being that turbofan have a large fan in front of the compressor that is the main source of the engines thrust. The fan is (as mentioned) ran by the turbines in the rear of the engine as stated in your video.
so in theory would it eventually be possible to just have thrust from oxygen? obviously not like this there's hardly any thrust coming out the exhaust but in theory would it be possible?
Did you know that Goerge Brayton... Inventor of the "Brayton cycle" only made piston engines? They were some of the first engines with enough power density to be used for motive power. They were used to power boats and a bus and a rail car. One was used to power the first self propelled submarine. If you want to learn about Barayton's piston engines search Brayton ready motor or Brayton hydrocarbon engine or Selden Automobile.
I was wondering something: According to the description, this is to scale. This means that resultant forces were proportional as well. Subsequently there should have been a lot of thrust produced, even with the relatively low PSI of the compressor. Am I wrong? If not, this represented quite a dangerous situation with persons standing so close by as there were no visible restraints to the model. Additionally, no one including the professor wore PPE, & I think safety has to always be paramount.
What thingiverse item #? Would probably have turned better using steam for the high pressure area. Since a jet engine uses the expansion of gasses in the high pressure area, the steam tho cooler than a flame would give a better turning speed.
I see you point but I was talking more along the lines of really learning how it works by stripping and building an old engine because the best way to learn is by doing, let them build plastic parts all they want I get that but its the hands on approach they need too, so they can look at the parts they are designing and they have a rough idea where they go in the engine, they can see what environment the parts work in, what the other parts are like, i.e. corrosion, burn marks, wear marks etc
Very accurate reproduction of a turbofan. Very similar to pw 615f, the one that makes the tomahawk fly. From this point to a functional one is not that far.
I am building a turbocharger complete with functioning wastegate actuator and blow off valve as part of my mid year project. Did you guys print the bearings or did you buy them? what kind are they (roller or bush)?
melihileri I was going to forget about bearings but decided to design every component of a turbo charger including a functioning oil gallery system. Are you not worried about replacing components that are eventually damaged by the heat produced to the shaft?
frank white sorry about that frank, im afraid i dont remember. i thought you were talking about the starter piece, which is what we didnt have. just looked at the article that covered our plastic engine: uvamagazine.org/articles/printing_awesomeness apparently we did have bearings to hold the dual concentric shafts up in place (which makes sense now that I think about it). Professor David Sheffler from Aerospace and Mechanical Engineering Department at University of Virginia (the gentleman in the video) is the right person to contact (if you can get to him). His contact info should be publicly available on UVA's website. Good luck!
Well, that all sounds very lovely and all. they could do placements in a "real" machine shop where we chase tolerances to 0.0001" of an inch, in the aerospace field 0.002" may as well be an inch depending on what the part will be used for, I fully agree and understand the limitations of your course and how you can only go so far into the field but you have to agree there is a big gap between training and reality, much like there is between theory and practice......
You'd prefer that the students who'll one day work on, build or design these engines to start working with no experience at all? For a call center that's fine, but for something that might carry my butt cross country to see the folks, it's nice to know they've done this sort of thing in school. Though, I wish a turbofan in this size was actually sold, most of the engines in this range are turbojets, which burn way more fuel. If they had made a real one, it would have cost a sizable fortune.
Of course it's not going to be a 'real' turboprop, an engine of that size would cost a huge amount of money to build due to the materials required to withstand operating temperatures on the first stage turbine. It's a pretty cool prop to get students interested in mechanical engineering, it's also a pretty cool bit engineering in it's own right considering its balanced well enough to not shake itself to pieces.
Hiya, wooho, i wish i could understand more about how a turbine works. Im working in a hover videogame for that reason, can i give here the link for it? Im a Indie dev. Thks and good job!
I had seen somebody make real electric motors using 3d printed parts. Its on RU-vid. I think they can spin up to 18000 rpm before destroying themselves. Look for Christoph Laimer- Halbach motors
Freeman Gentlefuck the professor worked at the company for a long time. I’m guessing he had drawn them up in the first place for the company so either recreated or somehow had access (uva being a Virginia public university, sometimes the engineering department gets research contracts that come with educational resources like this).
if i was a teacher i would place a turbojet , you know , one of these homemande jets with a turbo from a car or truck in that classroom , and start it up , they will understand the principe in one day even less in 5 minutes.
Next step, alloy 3D printing and using Jet A... it's been 7 years since the first PLA 3D printers have been available. Now you can 3D print using Titanium filament and some other 'interesting' alloys.
+MarbleDemo Amen to that! Sure, when it comes to mathematics engineers can solve complex calculus equations on one hand 100' up in the air on a high wire balancing a tray of glasses in the other hand standing on one foot balancing a beach ball on the big toe of their other foot all while having a gorilla fuck them up the ass but give them a set of tools and tell them to take an engine apart they're as dumb as a bag of rocks. Like my dad used to say: "just because you're educated doesn't meant you're smart" and if I've seen one instance of where some college educated stooge has degrees out the wazoo yet zero common sense I've probably seen a billion!
+Phayzyre105 buddy it's meant to teach undergraduate students how to use 3D design software to design (not mathematically, just art design practice) and build parts then machine them down to a precision (I think we did .002 of an inch) in a shop using tools and machines, then put them together into an assembly in which parts fit each other and move together. I'd say there's plenty to be learned there and they apply to lots of other areas. The pressure, hear, fuel, ignition, etc. all that apply to a few select people who choose to actually do engine design and manufacturing for a living. We mostly took the skills to prototype new ideas. Can't cover everything in a simple 3-credit undergrad course, nor would anyone want to. Also, trust me, engineers respect mechanics way more than you think. the two professions require mastery of a completely different set of skills. No engineer claims they can do a mechanics job.
melihileri As a nearly 30+ year aviation technician I know all about jet engines, reciprocating engines, turbo props, etc. No, I'm not saying that all engineers are assholes but I can tell you from experience, the good ones are very far and very few between whereas the others are so infused with conceited arrogance and look down their noses at people you could wring it out of them like squeezing a sponge! I to have a four year degree in operations management and I deal with engineers all the time, especially the ones who think they "know it all." But I'll give credit where credit is due; when you wrote "we mostly took the skills to prototype new ideas" really speaks volumes. For millennia the innovators and inventors have been not necessarily people with intellectual smarts but those who could comb through the depths of their imagination take an idea in their heads and with their hands build some amazing things. Engineers simply took those ideas and further advanced them. Sure, there was many trials and errors and yes some fatalities also ensued but my point was if you have all kinds of smarts but can't imagine and innovate you're pigeonholed. Even Albert Einstein said that imagination is more important that knowledge.
Mike Ponder Precisely!! And speaking of the SR-71 Kelly Johnson and his team built it with slide rules, pencils, paper and their imaginations. Some of his team weren't even degreed engineers! Nowadays we have what....a gaggle of MBA and PhD toting engineers who have a battery of ultra super sophisticated computers, software that's out of this world and a plethora of design knowledge yet we cant seem to build diddly squat nowadays! It's like we spend ten years building a prototype and another X number of years testing the damn thing and by the time it's ready for service the desire to even want it is killed off thanks to cost overruns, schedule delays and engineering changes. The F-35 is running into that problem right now as we speak!
tbh i'd prefer if students had an actual engine to train on, that way they know exactly what their dealing with when it comes to this high level of engineering
Planes use compressed air to start their engines. It's more efficient than spinning the shaft with an electric motor, which would then need to be built to withstand the combustion temperatures. Also note that this is only a model, and demonstrates how a real jet engine would work... without any boom or bang
Hello i am khodor Shehab I am a mechanical engineer I am planing to do a similar project a home I wish you can help me by giving me sort of paper or guidance so I can walk on through the procedure thank your
