Introduction: The Recycled Jet Engine

About: I'm a Mechanical Engineer who has been a part of this community for over 10 years! My interests have evolved over time, and now center around 3D printing.

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.


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..


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..


Step 1: How It Works

Fortunately, I was not without knowledge in my endevor. Being the nerdy teenager that I am, curiosity had spurred me during the late hours of the previous few weeks to discover how exactly we are able to fly. This gnarling curiosity led to a Google search, and many hours of discovering the magic behind what is.. a jet engine

So how does a jet engine work?
As my dramatic narrative of the project mentioned above, I spent a fair amount of time researching how the engine worked out of curiosity. I encourage you to do the same, but I'll try to supply you with enough information to build the jet without doing too much.

  • First, air is sucked, or in our design, fed into the engine, through a fan.
  • The fan pushes the air further into the engine, compressing it further
  • To keep our fuel burning, the air enters the combustion area through what is called a flame tube(also, "flame holder" or "can")
  • The high pressure air and hot exploding fuel, rush towards the exhaust, through another fan, also known as the "turbine" of the engine.
  • The rear fan that is pushed on by the faster-moving gases drives the front fan, causing more air to move into the combustion area, beginning a cycle.

If you do not understand, please take a moment to examine the diagram below, showing the flow of the engine.

I cannot stress enough that you should be intrigued by this engine and want to do your own research on it. Some sources I recommend are here:

Step 2: Gathering Materials

I looked around me, all materials already at my disposal, waiting to be transformed into something incredible.

The things I used for this project are as follows:
  • An assortment of tin cans
  • A coat hanger
  • Some brass tubing from the local hobby store
  • JB Weld
  • A dremel tool
  • A leatherman multi-tool
  • Sandpaper
  • Electrical tape
  • Rubber Bands

I personally believe that in order to do any project you are forced to innovate. You probably won't have the exact same materials to work with, but use your imagination to pull this off with what you have around you!

The only thing that I don't think you can do this without is the JB Weld, which is why it's bolded above. I used this to attach just about everything together, so I don't think you can go without it.

Step 3: Beginning Construction

It was dark, in the late hours of a school night when I first began to construct my machine. I began dremmeling ever-so precise shapes into the cans. As the cans shrieked and sparked my vision was slowly taking shape into the engine I had imagined. The horrible sound filled my ears and the fumes of teh dissipating metal filled my nostrils. I could feel a fine dust of metal lightly coat my skin as the metal wore away from the can.

The first thing we need to do is form the front, main part of the engine that will house the flametube and the fan shaft. This is the orange section in the diagram. We will refer to this as the "main housing".

To do this I took a peach can, which has a wider diameter than most cans, from what I have seen, and cut a hole in the lid as close to the center as I could get.
I placed the lid near the back of the can to mark a spot for a whole inthe back. The holes will need to be slightly wider than the diameter of your coat hanger. These holes will serve to support our shaft and fans.
I used a ruler to mark an "X" shape on the lid of the can. we will need the front of the engine to be open to allow for air intake. I then cut the triangle-looking piecesformed by the "X" shape out of the lid. This piece will be called the "lid", and we won't need it until the very end.

Step 4: The Flametube

Now I knew I must begin the most vital task: Assembling the flame tube. From my research, I knew this very part would make or break my project, and that it had to be done to the best of my ability.

The next step is to assemble the flametube. If you are reading the dramatic narrative, then you know this is the most important part. This is the purple-ish section in the diagram.

To make this I first selected a can with about a half inch smaller diameter than my peach can.
I then cut a few centimeters off of the top of the can to leave room for the front fan that will go there later. We will refer to this as the "flametube can".
I took the lid from an identical peach can and cut and dremeled until it fit tightly inside my main housing. We will refer to this as the "flametube lid". (This part may be unneccesary for you, depending on what the lid looks like coming out of your can opener.)
Make sure it's a snug fit without getting it stuck, as we will JB weld it in later.
Mark and cut the second lid similar to the first, but make the triangular pieces smaller, to allow the flametube can to be attached to it.
Next align the flametube lid to the back of the flametube can to mark and cut a hole for the fan shaft.
Then align the flametube lid with the front of the flametube can and JB Weld them together.
Rubber band them to keep them aligned and steady and allow to set overnight. The combination of the flametube lid attached to the flametube can will now be referred to just as the "flametube".
Once the JB Weld has set, poke or drill holes along the side of the flametube to let air through.

Step 5: The Exhaust

Having both my main housing and flametube completed, my vision was piecing itself together much more nicely than anticipated. A nearly imperceptible, yet present, flame of excitement sparked within me. I knew my next move was to complete the exhaust.

After what you've gone through so far, this part is really a piece of cake. This is the green part in the diagram.
Fist I selected a can slightly smaller in diameter than the one we used for the flametube. This will be referred to as the "exhaust can".
Next trace the exhaust can onto the back of the main housing. This was pretty easy because it lined up perfectly with the grooves on the bottom of the can.
Draw another circle with a smaller diameter that you will cut along on the bottom of the main housing. We need a smaller diameter than the actual exhaust can so that we have room to JB Weld it.
Use a ruler to draw yet another "X" type shape on the back of the main housing like before. There should already be a hole marked for the shaft to work around.
Cut out the triangular-like pieces on the main housing.
On the exhaust can, draw a circle on the bottom to be cut out. Again, there are awesome grooves to help you. You'll want to keep the resulting disk in tact for the fan shaft later.
Finally, JB Weld the exhaust can to the main housing. This combination will now be referred to as the "housing".

Step 6: The Fuel System

Alas! Every project must be related to fire in some way! This was however, a challenge for me to solve, as the hours of construction quickly dissipated into nothingness. It had to be done, even though it meant I would have to sacrifice the idea of all-recycled to protect my safety.

This part was tricky. I planned to run this off of the butane in disposable lighters, as they're cheap and have a built-in fuel control mechanism, yay!.. Now, it doesn't seem like a very good idea to build any sort of system that is going to be responsible for directing flammable gas out of less-than-reliable recycled items, so I used some brass tubing from the hobby store. I could have used four lighters, and the brass fittings from disposable lighters for fuel injectors, but I wouldn't be able to deliver fuel from each lighter at the same time, light it, and try to get the fan shaft moving, just not enough hands. Your fuel system will depend on what fuel you're actually using, so it could be very different from mine. This part isn't pictured in the diagram, but the red arrows depict where the fuel would enter.
Now for the actual steps, I first bent a piece of brass tubing roughly around the wider part of the housing.
Then, I drilled four equally spaced holes around the main housing, in front of the flame tube.
Next, I drilled four holes in the flametube adjacent to the ones we just drilled on the housing. The holes should be on the flat space between where the air is directed and the side of the housing. This should make more sense if you look at the pictures.
Next, I cut four small pieces of the brass tubing and bent them into a sort of "L" shape and slid them through the holes on the housing, and through the holes on the flametube.
Then, I JB Welded them into place, really globbing it on there to keep everything pressure tight, hopefully. You should let this set overnight.

Good morning sunshine! Since the JB Weld has set up, here's what to do next.
First, we're going to cut some notches in the brass tubing that is bent around the wider part of the housing where the "L" shaped pieces are sticking out. These notches will be a little wider than the outer diameter of the tubing, so that the "L" pieces can stick into them, allowing fuel flow.
Next, align the "L" pieces with the bent piece of brass tubing and secure them loosely with thin strips of electrical tape.
I then used a lighter to melt the tape a little bit, hoping to make it tighter on the tubing, but I don't know if it really helped much.
Then we're going to break out the JB Weld again and REALLY glob it over the joints between the "L" pieces and the bent tubing so that no fuel will leak out.
Let it set overnight, and you may have to patch up some spots tomorrow, and let those set.

(You may be thinking "Jeez, I'm using a ton of this expensive JB Weld!" You're really not, I used a little less than half a tube, and I had a ton of mistakes that I didn't document that used a lot of it)

Step 7: The Fan Shaft

The time had come, the part that I had feared since I began the build: The Fan Shaft. The only part that moves on the whole engine, but yet actually makes it work. a failure here would destroy all that I had done already, and yet, I trudged on.

This part really isn't super difficult. I really knew nothing about aerodynamics, or how an ideal fan would work, so I pretty much made it up as I went along, and made a bunch of mistakes. This is the light blue part in the diagram.

First of all, you should cut out the middle bottom part of your coat hanger that will be used for the shaft if you haven't already.
For the fans, the first thing you need to do is find the small circle that we cut from the bottom of our exhaust, this will be our rear fan.
Use a ruler, and do your best to find the center, mark it, and cut a hole.
Draw a circle round the center hole that will mark how far the blades reach towards the center.
Draw a diameter with your ruler, and continue dividing the sections until you have the amount of blades you desire. Mine has six.
Cut along the lines to make your blades and bend them in one direction, since this is the first one, it doesn't really matter.
Place a little bit of JB Weld where the blade contacts the small circle you drew to reinforce it.
Obtain a can lid slightly smaller in diameter than the diameter of your peach can of the housing, mine was from a tomato sauce can.
Same thing as the rear fan.
Mark and cut the center.
Mark and cut blades, I used a couple more on this front fan.
Bend blades into shape, making sure they are going the same way as your read fan.
Reinforce joints with JB Weld.

After the JB Weld sets on your fans, slide the back fan onto the shaft, the coat hanger and JB Weld it in place.
Slide the shaft through the engine, making sure the back fan isn't caught on anything.
Slide your front fan on the front of the engine, there should be room for about an inch of the shaft to protrude past the front of the engine.
JB Weld your front fan in place.
Let the many JB Welded items set overnight.

Step 8: Touching Up

The fire of excitement that had sparked in me earlier was now roaring with an uncontrollable yearning to run the engine. It looked like it should work, and was calling me to start it and propel myself at high speeds down the pavement, cherishing those strange looks from my neighbors as signs of a job well done. But lo, I wasn't finished yet, and I pressed on evermore through the night.

Now, for the most part the job is done, except for some tweaking. I did spend a ton of time tweaking. Some tweaks I had to do are as follows:
  • Add on the front cap on with electrical tape, I had to be able to move it around a bit, to get my fan to fit in.
  • Bend and trim the front fan so that it would spin freely.
  • Mess around with the fuel system a bunch.
  • Add a small piece of plexiglass to the front of the shaft to keep the shaft in place.

I thought that list would be longer.. Anyway, getting the fans and shaft all spinning freely without catching on anything was the biggest challenge, and took a LONG time.

Step 9: Finishing Up

And now, good people, I bid you adu, for my work here is done. I have delivered to you my story to the best of my ability and now must depart, but I wish you all the best wishes ever.

Alright, yay! We're done. Just as a final word, I'm going to point out again that this project uses nearly all recycled materials. It may not seem like it during the build, but all the major components of the engine are recycled, saving our planet - Yay saving the planet! I actually forgot at points as I was building this that all this stuff would've been wasted. I put a lot of work into this project and hope I provided enough information for some of you to duplicate this.

Ok, three more things that would really make me happy:
1. Comment! I never seem to get many comments when I put things online, either on here or youtube or anywhere else, and I like comments! : )
2. Rate! I often forget to rate things, but it would be nice if you didn't.
3. Vote for me in the Epilog Contest! I'm kind of submitting this late, and I don't really think this is good enough to win, but only if you think it's helpful and informative should you vote for it.

Thanks for reading!

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