Introduction: Beer Can Jet Engine: Mk II

Picture of Beer Can Jet Engine: Mk II



This is the new and improved version of my Mark I Origional Beer Can Jet Engine. It has a far more severe throat in the air intake to aid compression, a new power suply that is variable and works of mains electricity (instead of a complex power pack) and an inline fuel injection system that opposes the direction of air to improve the fuel-air mixture.

The results were mixed, it wasnt the massive improvement in performance i was expecting but i am pleased that it wasnt a complete failure, i have learned alot about the construction and opperation during my investigation and experimentation and hopefully in the Mark III Engine the culmination of the two builds with result in one engine of definably superior performance.

Visit my website for more information and other similar builds:

Step 1: Gather the Materials and Tools You Will Need

Picture of Gather the Materials and Tools You Will Need

Materials Required:
@ At least 4 Steel cans, specifically the taller ones and bigger ones are better.
@ Copper tubing, i used half inch diameter plumbing tubing i had in the garage for its rigidity as this will hold your engine together.
@ Some flexible plastic fuel hosing long enough for you to be comfortably far enough from a running miniature jet engine, 3m did me, I got some from my local model shop used for nitro cars.
@ An old hair dryer or other air moving device, leaf blower could work, or a ducted fan/propeller.
@ A variable resistor or potentiometer, I used a dimmer switch of a house light switch in series with the mains power pack.
@ A length of wire as long as your rubber hosing at least, two wires needed to power electric motor for your fan.
@ Really small drill bits and a drill, 1mm or less for fuel nozzles.
@ Tape, adhesives and solder would be helpful.
@ Insulation tape
@A solid piece of aluminium at least 2.5cm diameter, cylindrical, aluminium to save weight and you want it to be up to say around 10cm long to improve fluid dynamics and less than around 5cm diameter. this will be the fuel injector and it will also double up to throttle the air flow to increase compression.

Tools Required:
@ Sand Paper, to smooth and remove paint.
@ Soldering Iron possibly to solder the powerpack.
@ Possibly a screw driver for any choca blocks.
@ Drill to drill fuel nossles with.
@ Sharp knife for cutting cans, tape and general use.
@ Scissors for cans tape and general use.
@ Pliers
@ Relevant Safety equipment, gloves, goggles, fire extinguisher and COMMON SENSE.
@Laithe to turn the aluminium. you may be able to use a clamped drill but be very carefull and use your college or schools laithe if possable as then you can be supervised by trained staff while it is in use.
@Assorted cutting bits, files, wire brushes, and other abrasives to

Step 2: Dissassemble the Ducted Fan

Picture of Dissassemble the Ducted Fan

Open your air moving device preferably old hair dryer or a ducted fan from a remote control airoplane. Cheep hair dryers available at supermarkets in the value range and ducted fans from your local model shop.

Obviously make sure if you are using a hair dryer it is unplugged first and you have relevant safety equipment. Take out the electronics and examine it, you do not want the heating coils of the hair dryer, just the propeller and motor; remove the coils if it is possible without hindering the devices ability to move air or blowing the motor, coils in series with the motor act as voltage dividers, removing them is potentialy fatal to the motor. I tried my fan, found it lacking in power so i slowly reduced the length of the heating coil in series with the motor which raised the voltage across the motor increasing its rpm substantialy. Be cautious while doing this because mine is tuned to the point where any further reduction in length would cause a high probability of the heating element getting too hot and burning out, replacing it would be difficult.

You should now have your ducted fan unit with two wires coming out. You now need to get an extension lead of at least 3 meters length in order to distance the controls from the engine while it is in operation. Take your variable resistor and put it in series with the motor, if you use the dimmer switch then it can replace the existing switch. Solder where possible and cover connections with insulation tape. Put the finished electronics in a project box or other non conductive container, safety first.

If possible use a battery rather than mains power as mains power is very dangerous and make sure you get a qualified electrician to check your work, this was easy for me as my brother is a sparky.

You should now be left with a power source connector, a box with a variable resistor in and long wires that are thick enough to handle the current leading to your ducted fan.

Step 3: Start Cutting Up Your Cans

Picture of Start Cutting Up Your Cans

Get your steel cans, make sure they are steel because aluminium will melt and disintegrate in seconds if you try to use it. Dispose of the contents and use a can opener to cut the top of then use a metal file or a sander or something to sand the bottom until the indentation in the middle drops out. if you have the tools then use a core cutter to cut the bottom dent out instead, it will most likely be faster. You should now be left with a can you can see straight down the length of. You can use some pliers to make the flange on the bottom of the can consenric with the outside if you want, this will also make the back hole bigger which is arguably desireable.

On another can cut the top and bottom of the can then slit its length so that you are left with a flat piece of thin steel, this will be used to make your adapter to attach the ducted fan to the combustion chamber.

Step 4: Make Your Combustion Chamber

Picture of Make Your Combustion Chamber

This section is very similar to the equivilent in my Mark 1 Engine. Get One of your cans with both ends taken off and then a second that is just the bottom half of a can with the bottom cut out. slide the shorter can over the bottom of the taller one and twist gently to secure in place with faith and friction.

Take a piece of the sheet metal from a can and roll it into a tube that fits into the two bottoms of the cans. Mark the join and cut off the excess leaving a 10-15mm overlap. put the tube into the bottom of the taller can and make sure it does not protrude into the combustion chamber too far, less than 5mm preferably 0mm which is possable if you have flanged the bottom of the can with pliers. Solder this in possition soldering the tube itself along its seam and the tube into the bottom of the can around its perimeter.

Slide the shorter can over the tube and push it onto the bottom of the tall can so it is secure and solder the perimeter join.

This is your constructed combustion chamber.

Step 5: Make Your Fuel Injector

Picture of Make Your Fuel Injector

My Fuel injector was a part from my brothers attempt to make a self sustaining jet engine while i was at uni. It is made from aluminium and i literaly just thought "oh thats about the right size and shape" and used it with very few changes.

you may find this section difficult without a laithe or a big power drill. You will need a solid piece of aluminium circular section about 3-4" long and about 2" wide, you then need to turn it down to the shape in the picture below or very close to it. This is the restrictor that reduces the area of the inlet manifold raising the input pressure and thus air density allowing for greater compression ratios and the potential for more expansion in the combustion chamber.

In retrospect this piece is far too heavy and a similar hollow alternative would have been far more effective performance wise.

Once your restrictor has been fabricated you need to drill a hole down the centre the same diameter as the external diameter of the thick (10-15mm) copper tube.

You then need to drill several holes around the pieces circumference just after its widest point. This is to improve air-fuel misture. These holes need to be as fine as possible to atomise the liquid fuel as it comes through the hole, Seriously the smaller the better. Mine were too big and i had fuel burning isues with liquid fuel.

Drift the copper tube into the thinner end of the restrictor and secure in place with solder for added security. bend the tube over at a right angle (I realise mine is not a right angle but i didnt have a pipe bender and this was sastisfactory as it fullfilled all the major requirements).

Step 6: Mount the Fuel Injector on the Engine

Picture of Mount the Fuel Injector on the Engine

Now you have the Fuel Injector built you need to mount it on the engine. This is the reason i used the 10-15mm copper tube. It is stiff enough to support the heavy restrictor securely.

Take a piece of the sheet metal from a can that has been cut open end wrap it around your ducted fan exhaust securing in place with a small piece of tape. Then put the other end into the entrance of your combustion cahmber as shown in a picture below. Adjust the sheet metal that is now wrapped into a tube until it is a tight fit in the combustion chamber entrance and allows for a little adjustment so you can change how far it protrudes into the combustion chamber by about an inch.

Draw lines on your tube to show where the overlap is and how far the minimum and maximum protrusion is. Now you need to take the can off the ducted fan again and find a drill bit the same diameter as your 10-15mm copper tube. Mine was 12mm. Clamp a scrap piece of wood in the vice and drill a hole in your tube on the join. Cut off any excess on the inside of the tube leaving at least 15mm overlap and put a slit in one of your holes, the one closest to the edge so that you can slide the copper tube into it without threading it through.

Reconstruct the engine attaching the sheet metal tube to the ducted fan in the position previously marked and test the fit of the fuel injector.

The sheet metal tube is not sturdy enough to secure the fuel injector to the ducted fan with so i used a piece of aluminium box section I "borrowed" from my brother. You could use any sturdy square section material, wood may even suffice. Line up your fuel injector central in the entrance to the combustion chamber and then lie the copper tube ontop of your box section. then draw over it in the outline of the tubes path. Measure and mark the centre of the path and use a set square to translate that line onto its top face and bottom face respectively. Meaure the centre of the sections length and mark it on again using the set square. Since my tube is bent i did not have one hole all the way through the box section rather 2 seoeratly drilled holes so that it would slide through.

Use a centre punch on your marks where to drill and drill your holes with a drill bit the same diameter as the copper tube so the tube is a tight push fit into the holes.

Put the components together and secure them in place with the strongest adhesive available, either solder or areldite/epoxy resin is recomended. Then for extra security I used some Duct Tape.

Step 7: Fuel Inlet Port

Picture of Fuel Inlet Port

The 10-15mm tube is too thick to deliver the fuel down as the engine does not require that much fuel. so i drilled a 6mm hole in the tube an inch from the mount and soldered in an inch long piece of 6mm copper tubing then cut off the excess 10-15mm tubing and crimped and soldered the end of the 10-15mm tube shut.

The 6mm pipe is where you will attach your rubber fuel resistant hose to.

Step 8: Put It All Together

Picture of Put It All Together

The combustion chamber and ductedfan/fuel injector should now be complete, put it together and get ready for a test run. I have experimented with different fuels but the most stable and easy to work with thus far is lighter gas, Butane that comes in a can similar to a large can of deoderant. These usually come with some small plastic adapters in the cap. Take the long one and push it into the end of your fuel hose you will use the valve in the can itself to vary the fuel input. Its crude but works.

Secure the engine for example in a vise or on the buggy like the one i made which i will upload the instructions for soon. Plug in the power, fuel tubes and don your safety gear. Do a last minute check that everything is set up right, that there are no leaks in the fuel line and that the electronics are properly insulated and have been checked by a qualified electrician. Make sure the engine is very firmly secured and that you have you man on stand by with the fire extinguisher, a guy to cut off the power if neccessary, one to film the test run and one on stand buy with a phone in case anything goes wrong.

Step 9: Test It

Picture of Test It

You have done your safety check and everything is ready to go. The engine is not self lighting therefore you will need a lighter with a very long handle or idealy a blow torch as the flame is harder to blow out.

Make sure the fan is always spinning blowing air through the engine BEFORE any fuel is put in as if it is done the other way around you could get the highly flamable butane on the electric motor or element which may lead to combustion in the wrong part of the engine and you may cause irreversable damage to it. The electric engine should not be span too slowly as this can damage the motor, do not be afraid to put a decent draft through the engine to start it but bear in mind that the less air is going through the easier it will be to start.

Once the fan is pushing air through the engine slowly push down on the butane valve to let a small amount though. At this point you should have someone pointing a blow torch flame in the exhaust path from a safe possition (not directly infront of it from the side).

You should get a flare out the back, as soon as this happens it is team work time, the fan controller should start to increase the air flow and the fuel controller should slowly increase the fuel flow while trying to keep an invisable flame or blue cone, no orange or yellow flames should be present but too little fuel and too much air will blow out the engine and visa versa you will get big yellow and orange flames which are not wanted.

Once you have the hang of it try making a rig for it to push along or hang it from the rafters in your garage and from the angle recorded in the video the thrust can be calculated via some simple maths.

Please can you send me any videos you make of your attempts or any photos as they will be much apretiated.


ashish tripathi (author)2015-10-20

if i will joint it with a small remote controlling plane... the i could able to control it... with remote....

if not then where i have to work in order to work in that way..?

well,your have to be able to control the amount of gas or fuel too

If you use an Electric Ducted Fan (EDF) with a speed controller, instead of the hair drier parts, it will be more easily integrated into the remote control plane. Otherwise you need to run the hair drier motor off batteries, and since it was designed to run off 240vAC, that gets complicated and difficult.

Then you can use a servo to push the butane can to squirt in the fuel.

A modified stungun/taser, or potentially; disposable camera, would be able to provide remote ignition.

Other people have done this. For example:

ThePyroDUCK (author)LetsBuildOne2016-09-14

I cant understand Why use an EDF?? Cant we straightaway put the motor with props inside the tude? That ll work like a duct and so an EDF wont it??

Charith95 (author)2013-07-18

i'm not clear how to start the combution .Don't we need to supply electric shock or fire externally to start the process. how to protect the fan by the combution ?. please reply me to my email.. email-

bman46 (author)Charith952016-05-08

Yes, u need to light the gas on fire when having the hair drier blowing air through it

200496 (author)2014-02-23


I am going to make this soon but I would just like to ask whether you need a fan or can you work without it ?

bman46 (author)2004962016-05-08

You need a fan to start the air flow, but u can use some other things to start the air flow

DEEJAY642 (author)2016-01-06

this is SOOOOOOOOOO cool!!!!!!!!!!!!!!! i so wanna make one of these

FERGUS BEN (author)2015-01-28

it works! nice instructable

BADAMI (author)FERGUS BEN2015-11-06

can u send me a video which shows how to start the construction ???
if u have one. please it would be really a great help
@Fergus Ben and LetsBuildOne

Matt428 (author)2013-04-16

On the title, it is supposed to be spelled mach II, not mark II

mlinguist (author)Matt4282015-08-16

Mark II is another way of saying version II.

LetsBuildOne (author)mlinguist2015-08-17

Thanks mlinguist, an apt username it seems. I've renamed to clarify.

jasshopper (author)2014-09-02

Is there any alternative fuel that could be used like petrol or kerosene if yes how or what changes should be done to this?

jakeuplink (author)jasshopper2014-09-25

If you could turn it into a mist (possibly from an ultrasonic humidifier attatchment) you could use any fuel in theory

thundercookie (author)2014-04-05


willdubz (author)2014-02-01

Im going to try to make this today but am going to try to have the power controlled by a raspberry pi and control the pi via local server. The only thing I wouldn't know were to find is the aluminum fuel nosel.

jegdhfgrbfhf (author)2010-11-02

This is brilliant,
I'm going to use a s- force fan that spins upto 40,000 rpm and they can lift there self off the ground does anyone have any views on it.

can u plz tell me in detail, how did you calculate the thrust for the mark 2 engine!!! I am trying to make a similar engine but am having some problems in the calculations.....
reply soon!!!

Aren't they around 48v? If your planning to have it mobile rather than on a static rig you may want to consider how your going to power it. They draw quite a few amps so your battery is going to need to be large and will deplete quickly... Sounds like it would be a beast though!

You may also find that it moves air faster than the burn rate of the fuel so the flame front won't maintain in the combustion chamber so you may need to use a flame tube to slow the airflow from the fan enough to maintain the combustion. This is simply a steel tube you squirt the fuel into with holes around the outside to regulate the air flow. If you google "Flame Tube" you should find several examples.


pyrotheblazehog (author)2013-07-22

whats the mesurements for this?

raghad muqaddas (author)2013-07-08


SkeptiCol (author)2013-01-01

I'm not sure if it's something Intructables are doing, or how this was loaded, but I am having trouble following as all the photo's are at the start and all the text at the end. My brain is having trouble matching the pics to the steps.

LetsBuildOne (author)SkeptiCol2013-01-01

Yeah this is new, It didn't always look like this. In future Instructables I'll make loads of little steps instead.

agm510 (author)2012-09-05

What did you use as a fuel

LetsBuildOne (author)agm5102012-09-05

Butane lighter refills. They come pressurised and don't require a regulator. I also tried petrel but it doesn't have atomising fuel nozzles.

Verstrent (author)2012-05-08

Can i use it for flying project such as flight shoes?

LetsBuildOne (author)Verstrent2012-05-09

Flying projects should be fine though I would need more information to say if they would be ok for 'flight shoes'. Just in case it was you're plan, it is not gradable that these engines could lift themselves vertically let alone a person aswell.

Verstrent (author)2012-05-08

if flying shoes sucesses, i could fly around the world

rayabel (author)2011-12-04

Please take several photos and decide if you need to take more photos until you get a focused photo.

Other than that, cool engine.

LetsBuildOne (author)rayabel2011-12-19

The engine doesn't exist any more and the photo's taken weren't for instructable use. They were mainly for posterity. In future I will make sure I get high resolution, focused photographs in future though. Thanks for the feedback.

I am from india and made an rc plane in brussels, I make rc planes, rc trucks, rc sidecar and rc speed boats I wanted to make something new so i thought to make an jet engine. Can you please tell me how to build it , Can I use iron (mosquito spray )cans, I used a hairdryer deduct fan and a rc helicopter motor.Can you tell me the what to do in the step 5 (fuel injectors).Please reply me as fasty you can . Please please please help help me!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Try the fuel ring from my Mark I engine:

The ducted fan and heli motor will work great. so will the mosquito can. make sure it is COMPLETELY empty before you think about opining it though and wash it thoroughly as the contents were poisonous.

Good luck :)

Thanks for a quick reply.About your engine my friend (the one who helped me in my projects and the owner of avionic modelsime in brussels sebastien maes thinks that the engine may burst on this temp. after a few seconds.And about the hairdryer fan he said it wont work . He told me to use a stainless steel can.And to use an edf fan.About the fuel it may explode so we may use kerosene. He told me that he can ask anyone to make an lathe fuel injector.He want the plans for it can you send me them on my email- , and if you want to make an engine which may produce a lot of thrust and work for a lot of time you can follow these steps :) Can you please send me some pdf on my email as I cannot be a member on this website as my mom won't allow me. :)

Won't the iron will melt at higher temp.

please send me pdf and plan for fuel injector

Iron and steel melt around 1500 dg C but your engine shouldn't melt, Mine didn't. To ensure this, sleeve the combustion chamber in a tube that leaves a gap around the circumference and overhangs the exhaust by a short distance. This will act like a venturi and draw cold ambient air over the hot combustion chamber, cooling it and aging to the engines thrust.

Don't use the fuel injector from this engine, it is heavy and didn't work well. Use the one off the mark I engine. That worked well.

An EDF we will work much better than a hair drier, if you have one, use it.

You can use kerosene but you will need atomising fuel injectors and a fuel pump. This is much more complex than using pre pressurised gaseous butane.

If you still want the CAD I can send it you but the mark I solution is much better.

Thanks again for a quick reply.About the fuel injector i will ask Sebastien maes and see what will he say.What can we do to increase the thrust? About the butane gas he said it is dangerous to use it and it may burst and harm us.Can you send me the pdf for this engine? Which engine worked better- mark1 or mark2 ?

Sleeving the combustion chamber in a second larger tube that overhangs the exhaust will increase thrust as it draws cold air in via the venturi effect, this air is heated while simultaneously cooling the combustion chamber, as the air heats up it expands, as this air is mixed with the exhaust gasses it produces further thrust. This is the same as most modern jumbo jet engines. The majority of the air bypasses the combustion chamber.

You can also increase thrust by increasing the power of the fan, the amount of fuel burnt and the temperature at which it is burnt.

If you use butane you should use a nice long delivery hose. The first time you use it, it will flush the air out of the hose leaving only butane. Without oxygen the butane cannot burn so your butane canister can be remote from your engine and it will be relatively safe to use.

The mark one engine was significantly better than the mark two. Mainly because of the fuel injector, it was heavy and didn't work particularly well.

I am e-mailing you the pdf's now

Thanks a lot :):):):):):):)

Wesley666 (author)2011-10-28

Been working on a jet engine again, its almost done and ready to test. It is a turbofan design, self sustaining, so no electric motor turning the compressor, and I made it from an old computer and a soup can. I used bushing from computer fans instead of bearings, I am hoping they won't melt, they shouldn't but its a possibility. The casing of the computer was steel so I used that to make everything. It was very hard to make 3 turbines that were balanced, but I did it. I am just finishing the combustion chamber and the turbine in the back that drives the compressors in the front. I used a long shaft from a CD drive, it was the shaft for the tray to go in and out on. Will post pictures of it sometime, and will try to video tape me attempting to start it.

Also, whether or not mine works or fails horribly, I had a great idea for the next one. First, I want to make it bigger, easier to work on, second I want 2 to 4 Fuel Injectors from a car that I can use to inject gasoline or other liquid into the combustion chamber and last, I want to get a machine shop to make some parts so they are perfect. I think this would step it up even more and produce something that would work without a problem.

Wesley666 (author)Wesley6662011-10-28

As well, a spark plug with a system that continually fires a spark every second or so, to make sure the thing stays lit and I don't have to light it with a torch to begin with.

LetsBuildOne (author)Wesley6662011-12-19

I currently have a bag full of fuel injectors, a high pressure pump, coil packs and a spark plug or two for just this purpose. This project is on the back burner for now though as the current project is an electric bike and research into water injection and hydrogen power for internal combustion engines.

Aron313 (author)2011-12-16

How much thrust?????

LetsBuildOne (author)Aron3132011-12-19

Around a pound or half a kilo.

hayme (author)2011-08-13

don't call me crazy but if you can make this thing stable and mount it on some kind of hydraulic device and put it on your arm, is it possible that you just have built a jet sword type thing? Tell me the possibilities.

LetsBuildOne (author)hayme2011-08-13

I suppose so. Especially with petrol as the fuel. Kind of like an arm mounted flame thrower if that's what you wanted.

rabb72994 (author)2011-07-22

possibly a spent C02 cartridge?

LetsBuildOne (author)rabb729942011-07-23

Yep, that would work.

About This Instructable




Bio: I build stuff because it isn't available to buy, or is too expensive, or the ones you can buy don't do what I ... More »
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