Simple coke can engine

This is a simple coke can Stirling engine you can make in under an hour. No epoxy or RTV needed, just super-glue. It's all supported by steel wire, with spade connectors for all of the bearings.

Important note: It has been found that aluminium drinks cans need additional cooling around the top because the aluminium is so thermally conductive. Use steel cans if you can, such as Pepsi, Tango etc.


Thanks to David Williamson for the diaphragm design/ construction method. Check out his website here!

Materials1 Coke can

• Steel wire wool
• 1.6mm steel wire
• Spring paper clip
• Normal paper clip
• 0.4-0.6mm fishing line
• Super glue
• Thin cardboard from a cereal box
• A balloon
• 6.35mm electrical connector/spade connectors .

Step 1 Open the can with a can opener

Open the top of the can with a can opener.

Comments

[pastorkirbyjohnson]

Middle School Science Fair, here I come!!!!
Awesome!
I had never even heard of a Stirling Engine until this instructable.
My kids and I will have a blast (in a good kind of way) with this.

[8v92]

Trying to figure out why this engine runs is like figuring out why a bumble bee flys, it should not run but it certainly runs quite well. The counter weight in the center seems to resonate and the flywheel is low mass but high inertia. I am not an expert but there are principals at work here that need to be studied. This is a great example of thinking outside the box.

[burnerjack01]

The principle is quite simple. If I may.... There is a displacer inside the can.
This displacer moves up to allow the air within the can to make contact with the hot can bottom. This expands the air which drives the diaphragm up due to expansion. The displacer then drops to the bottom of the can which insulates the air from the heat thereby allowing the surfaces not exposed to the heat to cool the air which allows the air within the can to contract.
The REALLY cool thing about sterling engines is if you drive the shaft instead of the other way around, it becomes a heat pump! Not bad for 1880's tech!

[burnerjack01]

I think it's AWESOME that you are introducing your kids to this!
Not only is this device classified as an external combustion engine and is truly a flex fuel technology which can even run on solar or geothermal heat.
In fact, any heat difference between the "hot cap" and "cold cap" will make it run. This goes all the way back to 1880's Scotland and I have read that it was devised to take the place of the dangerous steam engines used in coal mining at the time. Not a bad job of design by a monk of all people.
Ther is a wealth of history associated with this device.
One last thing, it has been said that this device is one of the most thermally efficient engines ever devised. Good luck with the Science Fair!

[rwcrocker]

Very cool! We built it today. It took a little more finesse bending wire than I had anticipated. If you don't balance it well enough, it wobbles like crazy on the wire legs even if you're holding the base.

We added a 15 mm strip of wet paper towel around the top of the can to act as a better heat sink - it helped a lot.
Thanks a lot for the great instructable!!

[scraptopower]

Wooo! First person to build this ? Please share some photo's if you can :)

The paper towel is a good idea!

Thanks!

[8v92]

I did not see the fishing line going to the displacer in the movie so I thought it was resonating somehow. I still think it is a good design and would work with multiple cylinders. Perhaps an affordable and practical vehicle could be built using a stirling engine.

[christpher]

I gust watched tow helicopters go by woooooooooow

[rikardom]

Awesome!

[tobune]

Very good concept. Trying to make it reality now.

[tokin]

Cool!

[mattle]

Yes it is!

[stumitch]

fantastic! i want to build one!

[teniva]

Just love it and I certainly must try it

[bhaskar0kumawau]

can i use a steel wire instead of fish line and tell me how it works??????

[begunia]

Amazing work my friend!

[kuruting]

Amazing...

[lepar]

Awesome work. Thanks for sharing it with the community.

[merkuri2]

Interesting I must say.Trying to make it now.

[kokina2]

You are awesome and creative!

[torina2]

Excellent work!

[Chowmix12]

I really want to do this project. I have all the things but the wire. Would paperclips work as wire? By the way, would a few drops of water make Stirling engines more effective? I know steam is 100 times the volume of water.

[scraptopower]

I wouldn't have thought paper clips would be long enough, even un-wound. You could try adding another coke can on top for the bearings like my other instructable "make a coke can Stirling egnine" . You can get this kind of wire at garden centres and the like, it's not usually expensive, don't get the really thin 1mm stuff though as that won't work.

My engines that have had small water leaks all splutter to a quick death, maybe it would work but you need to be quite precise in the amount of water :)

[Chowmix12]

the paperclips worked for the crankshaft, I made a flywheel of cardboard and glued it onto the crankshaft. For some reason I couldn't get the engine to work.. I gave up on it...

[sandra-1]

Very cool! We built it today.

[MCzone]

learn to measure
how does 15 cm get that far
you made me waste 30cm of wire.

[MCzone]

oh im sorry i made the mistake

[scraptopower]

Use it for the connecting rods.

[MCzone]

I started using it for the stand and the loop above the basket <:(

[wiinick]

I almost id that too, but my base looks nothing like the picture, but does it work, yes.

[MCzone]

I never did get that tin can working, but its cool

[nishi biswas]

I have tried to assemble a Simple Coke Can Engine, but after several attempt, I failed, so please let me know how would you help me if i become a paid member.

[scraptopower]

Authors on this site are not paid, so being a paid member will make no difference.

Which steps are you having difficulty with ?

[pauli2]

Amazing work have you done.

[scraptopower]

Thank you.

[antonio23]

I found this project very interesting! Trying to make it now.

[wiinick]

well i assembled the thing sadly it doesnt work, its my fault so i am going to see if i messed up with the counterbalace, and there maybe a lot of friction.

[joehudy]

this is probable a dumb question bot what does the displacer do?

[wanzaidi]

Hi every one,

I found this project very interesting. But one question keeps bugging me - why fishing line, not a wire as the conn rod for the displacer?

Wan
p.s. I will be making one soon.

[bryahn]

Sorry if this is a stupid question, but instead of a candle, could you heat this with say a wire coiling around the bottom 2-3 inches of the can? similar to say a water heater element maybe.