Instructables

There I was, in my corner of the basement, my collection of salvaged tin cans sitting in the corner, pondering what I could make... Then a brilliant idea hit me as if I were taking a nap on the train tracks.. I would make a jet engine, from nothing but recycled materials!!

So when I thought about it, having all recycled materials really wasn't possible with my current supplies, while still making it somewhat safe.

EDIT: PLEASE NOTE THIS PROJECT WAS NOT SUCCESFUL, MEANING THE JET I MADE DOES NOT WORK. I HOPE YOU CAN LEARN SOMETHING FROM MY WRITE-UP.

EDIT:
Monday, April 13, 2009: I tested the engine today. I tried to use hydrogen-oxygen gas from my hydrolosys setup and melted part of my fuel system. I will have to do repairs before I can test it again.. I apoligize to everyone who is waiting for a video of it's probable destruction..
Thursday, April 16, 2009: Since last time I purchased a windproof lighter so that I can use the fully combusted butane to run the engine. I held the flame up to the brass tubing, cans, and JB Weld and none of them looked like they were melting. I made a small adapter thing out of spare parts I had lying around so that the lighter could be connected to the fuel input. I had to wait overnight for the JB Weld to dry.. So maybe tommorow, or Saturday..
Monday, April 20, 2009: So my fuel system failed and failed and failed, and melted, and failed again and again.. In an attempt to get something slightly working I went ahead and cut a hole in the side of the main housing and stuck my windproof lighter in to see if I could get it working that way, and the flame went out in less than 10 seconds, I'm not sure why. It was a fun project, and hopefully you can learn from it, and maybe make it work.
A couple improvements I can think of would be:
  • Copper fuel line, instead of brass for a higher melting point
  • Wider diameter fuel line, mine was about 1/16" outer diameter, and even smaller inside, which ended up being way too small
  • make sure that whereever your fuel inputs end up, they have a good amount of clearance from the flametube, during final tests, it was melting from the butane flame..

SAFETY:

This Instructable involves:
  • Cutting stuff
  • Fire
  • Flammable gas
  • JB Weld
  • Sharp Objects
  • Potentially fast moving objects

EDIT: My email recently decided that the instructables robot was spam, so I haven't responded to a lot of comments that I didn't know about. I'm sorry, but I can't do much about it, I tried to fix the problem in my email client..


PLEASE READ THIS INSTRUCTABLE IN ITS ENTIRETY BEFORE BEGINNING TO CONSTRUCT YOUR OWN.
I AM NOT LIABLE FOR ANY RESULTING BAD STUFF THAT OCCURS BECAUSE OF THE INFORMATION PRESENTED HERE.
 
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harstahl9872 months ago
Send me a video.
Hassan 99 months ago
it will not work because only fuel and air mixture will come out it will not burn
The main reason this will not work is because a jet engine will need a combination of compressor-turbine, if you look at the schematics of a real jet engine you will see that for the type of jet engine you were trying to build you would have needed first to create a compressor using a combination of rotors-stators in a convergent chamber, then you would need to incorporate the fuel delivery system and ignition system after that, then you would need the turbine, in an opposite combination of the compressor, that would be stators first, then rotors, in a divergent chamber, ah, and the turbine needs to have a lower number of rotors-stators than the compressor. you would actually be able to use any fuel, but i would recommend actual hobby airplanes gas... or jet fuel... but u might find that harder to come across... you will need to make the turbine blades-rotors from heat-resistant materials, as well as the combustion chamber, and remember that the objective of the fuel injectors is to make an aerosol out of the fuel, so you would need some sort of pump to deliver the fuel at pressure to create an aerosol at the injectors, this pump, with ingenuity can be driven by the jet engine itself after is started by means of external force (meaning for a small engine a crank or so, and a spark plug or some type of ignitor in the combustion chamber). After u get all that working (which might never happen for you, based on the designs you have made so far...) then u can add an augmenter, which is somewhat shaped like an hour-glass and will take advantage of the "Venturi" effect to increase the airflow the engine is pushing.... There's also the afterburner, but that would be too complicated in your case. the whole idea of the Ecological Jet Engine, made out of recycled materials is quite ridiculous (no pawn intended), sorry to say, but a jet engine burns hydrocarbon based fuels, that's not very ecological, and recycled materials are not fit to resist the high temps in the combustion chamber and turbine. I hope my comment gave you some insight on the real workings of jet engines and drives you to search for more content you can find all over the internet on their designs, (also, there are pulse jet engines, which are much easier to construct and you might actually find it possible to build one with not so much effort) I believe that you have the passion to get one working if you get the right designs and technical knowledge. Good Luck! Morgoth "If you think things can't get worse it's probably only because you lack sufficient imagination."
fozzy13 (author)  morgoth_lord4 years ago
I appreciate your information. I have researched it much more since writing this Instructable and have found what I did wrong. As I said in the Instructable I did intend to run it off of hydrogen, making it ecological. I have ideas for a second turbine engine, but not enough time and materials..
Yeah, hydrogen is ECOLOGICAL, but is it ECONOMICAL? NO! Try propane. Much safer and easier to come by.
oh how i do not like making comments on old posts, but you are wrong. it can be economical if you make it yourself www.youtube.com/user/01032010814‎- look up his video on how to make fuel from water, its a lot cooler than it sounds.
fozzy13 (author)  yardkarter3 years ago
Hydrogen may not be particularly economical at the moment, but many people are working to change that. The most convincing attempt I have seen involves a genetically modified bacteria or algae, that produces hydrogen. Also, I am currently working on a solar array to directly make hydrogen. However, I believe I mentioned somewhere that at one point I switched to using butane, which is similar to propane.
Yep, I saw abt the hydrogen... not the best idea for jet engines, but I do know it was all in the ecological intent... I don't have much time to get into building one, but as soon as I can find the time I will be making a small jet engine, I will actually have the parts machined from cad designs of my own so they will be up to specs, but the heat resistant materials for the combustion chamber and the blades in the turbine will cost me a pretty penny. maybe i can get away with having them made out of carbon steel and see how long do they last... anyways... If i get anything going i will post, including CADs...
flyboy19421 year ago
Try starting your next project as a ramjet, it is the same design WITHOUT the fans, and is the simplest jet there is, period. After all, all a jet is is a furnace that vectors its exhaust to produce thrust. Once you have a working ramjet, then you ca get fancy and add fans, making the turbojet you want, but for now, kiss (keep it simple, stupid!) As for all the noise about melting points and not good enough, there is an instructables that makes a working jet/rocket hybrid out of a pickel jar, so dont dissmiss the tin can so quickly. Hope this helps.
fozzy13 (author) 4 years ago
I haven't, as I didn't know there was anything called stove glue, but I believe most any fuel will still burn hotter than that..
n108bg fozzy134 years ago
Well, that's where you may be wrong. A lot of people have copper fuel lines and copper nozzles in their working truck turbocharger jets. Epoxies have a questionable working temp, somewhere between 150 and 300 degrees farenheit. A glue like stove glue is designed to work in extreme temperatures, well in excess of what the metal can do. I would question highly whether the JB weld could hold up to that kind of temperature (which is over 300 degrees for everything aft of the fuel ring.)

turbojet n108bg3 years ago
Actually, fuel lines are external to the combustion chamber. Mainly the parts disposed of flames are the combustion chamber itself including the flame holder, the internal fuel injection nozzles and ingnitors, the exhaust the turbine and the housing around them. A usual EGT value is from 500 to 700 in celsius, so for at lest the above parts, you should use materials only that are guaranteed to resist 700 preferably 900°C. I am not sure if foodcans are able to handle that. Also, I don't know what amount of heat the stove glue can take, however if you tell me "up to 1000°C" that means it's probably not safe enough for the critical components.

fozzy13 got stuck mostly because of erratic design. The very first thing that shows up is that there is no compressor in his build. This is essential to get the fuel burned (and thus the work done). The project would have to meet the following, very minimal, and by no means complete list of requirements:

- Air gets sucked into the air inlet
- Air gets compressed by the compressor (slowing down the flow raises pressure, however under a certain flow-speed-limit, the compressor will "stall")
- Pressurized air (rich in oxygen) gets into the combustion chamber
- Fuel gets "sprayed" in the pressurized air
- The mixture burns due to the present heat or ignition
- Expanding gases exit through the exhaust
- Flow from the exhaust of the combustion chamber pass through the turbine
- The turbine forces the compressor to continue its rotation
- Gases leave the engine (intake must not exceed outlet or flow will stop because of air jam)
- All the parts starting from the combustion chamber and its components must me made of a highly heat-resistant material (Preferably the whole engine)
- Rotorblades/Fans must be well-balanced
fozzy13 (author)  turbojet3 years ago
Wow lots of information there! I have been considering starting another attempt at a jet engine soon, but we'll see what kind of time I have.

Thanks for the comment!!
OH! I forgot another important warning. Looks like it isn't mentioned in the docs here. Rotating speed of your fans must be restricted under MACH 1, otherwise the parts will break off causing serious damages, injuries or even death. Thus you must keep you fans under (20417.7 / (fan_daimeter_in_meters * 3.14)) RPM for the above security reasons.

For example if you choose the Cummins ST-50 to make your jet out of, it has a diameter of about 5 inches, so for simplicity, let's say this matches the diameter of the compressor. Then, your diameter is 0.127 meters, so the max RPM should be under 20417.7 / (0.127 * 3.14) RPM, that is 51174.4548 RPM

Actually the centrifugal compressor of the turbo seems to be resistant to the sound barrier (as people often mention 100000 RPM operations), however a 5 inch axial compressor would possibly "explode" above 51174.4548 RPM
This is not mandatory of course, but it is wise to keep in my when experimenting. Supersonic fantips must withstand the extreme conditions...
i m interested with th theories & calculations to design the jet. so can u tell me what do u mean by the above no: 20417.7 ?
To be honest, it was quite a time ago and I don't remember where (or out of what) I've found this value. If I put it simply, you have a 0.127 metres diameter, which in turn gives you a circumference of 0.39878 (around 40cm).
This, to reach 340m/s (the speed of sound) needs to have an RPM of 852 so I really don't know. I've abandoned researching this stuff long time ago. My apologies.

If you would like to build one, buy a turbocharger first and then look around for info on how to attach a combustion chamber to it, give it a fuel and oil supply and always wear some ear protectors.

Regards
I feel it impotant to warn you: I'm new to this stuff. The things I mentioned above are those I found out till now, and far less than complete. I've even omitted some details in order to keep the comment as short as possible.

This thread can help you a lot (as driving you through the steps of making a simple home made jet engine):
http://www.instructables.com/id/How-to-build-your-own-Jet-Engine/

Unfortunately the workaround of attaching a shaft to get power out from the engine is not described here, so it is up to you. If you want to simply use the thrust, then this is a complete step-by-step tutorial for you. It works with nearly any fuel of your choice. (I didn't try it because I don't have funds to buy a turbocharger and a welding machine).
You can find lots of vids about these jets made out of a turbocharger on youtube. I warn you again: These stuff are extremely loud, so never experiment without a good hear-protection.

Also check out this one: http://www.instructables.com/id/Design-a-Jet-With-The-Unknown-Basics/

It's got a lot of important basic information that helps thinking around your project.

Good luck!
Great effort! But i really don't think it's possible to make a crude jet engine out of tin cans and some metal scraps, you'll never get enough compressions lol. But still very nice design, if you had machined parts you could probably make this work!
beehard443 years ago
did this actually work? a video of it running would be awesome
fozzy13 (author)  beehard443 years ago
No, this did not actually work, or else I would have made a video.
this is not gonna work...the problem is the space between blades and the case, the blades shape and the number of blades...as n108bg said, this type of engine work's with high rpm's so it's like a ticking bomb...if you really wanna build this turbine, you should try good materials not food cans. i understand that you're trying to build something complicate, easy, simple and cheap, but it's hard... sorry for my bad writting ;) i'm romanian
Be more imaginative
excuse me?...i don't understand what did you want to say...
micnic3 years ago
Dude u are brilliant and imaginative.dont be discouraged because it did not work.try using an electric motor to keep the blades moving before firing
___3 years ago
I built this. I haven't had any luck with it, but the Instructable was in-depth. It looks great and is an awesome conversation starter.
fozzy13 (author)  ___3 years ago
Awesome! Thanks for the comment. Do you have any pictures of the build or finished product??
___ fozzy133 years ago
Ill try to take some
eric m3 years ago
Sorry kid.

you don't know anything about jets or heat or melting point.

tin cans? lol. come one. read and learn. try the library for rc books.
Ki1o4 years ago
It sure looks cool, I can give you that.
fozzy13 (author)  Ki1o3 years ago
Thanks!! Unfortunately thats all it has..
kikiclint4 years ago
I wonder if tin can blades like yours would work for a turbomolecular pump to create high vacuum? They spin at around 80000RPM though, so balance is of utmost importance.
fozzy13 (author)  kikiclint4 years ago
Hmmm, maybe that would work, but these blades specifically wouldn't work, as they are definately NOT perfectly balanced..
yeah, but they might be a good start with careful detail to precision. I wonder if they could handle the strain from centipetal acceleration? I wouldn't want to be nearby if it failed.
fozzy13 (author)  kikiclint4 years ago
I suppose they may be useful as a first mockup, but other than that I wouldn't want to be near something that fast made from cans that wasn't computer-cut.. And, bearings would be a must..
tjdtjd14 years ago
The explanation was very helpful - i'm probably going to make some kind of a jet engine for my AS tech project
fozzy13 (author)  tjdtjd14 years ago
I'm glad it helped you out, if you make anything share it with us!!
Romanader4 years ago
Hey, hydrogen isn't a bad idea. With a touch of research, it would make one whallop of an engine. Look at the Continuous Detonation Engine (CDE) or pulse detonation engine (PDE). One other example is the oblique detonation wave engine (ODWE). They run off of the hydrogen/oxygen golden ratio detonation principal to attain theoretical hypersonic speeds of up to mach 5. Granted, rolled tin/steel cans might not be the best choice of materials for this, but you have one hell of an idea rolling here. Nice job.
fozzy13 (author)  Romanader4 years ago
Thanks! I'll definately try to look into those
crysec4 years ago
Come on morgoth_lord give him a chance, all what has been invented is for 2 reasons WAR or ACCIDENT , fozzy13 keep it up, just do a little more research, and u will come up with an improve
jamster5454 years ago
I think part of the problem is you might need something to start the fan blades spinning. In an aircraft jet engine they don't simply light the fuel and let it go, they "spin up" the engines first (father is an airline pilot). If you get the blades spinning first before you add ignition it might work better. Even blowing compressed air through the intake might get them spinning.
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