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Be an Aeronautical Scientist: Make your Own Jet Engine for a few Pennies.

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You can make a real jet engine for five minute's work and the price of a spoonful of meths - how cool is that?!?

I doubt there's a better way to re-use all those jars under the sink. Much more fun than a trip to the bottle bank.
 
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Step 1: Materials and equipment.


Stuff I had lying around:

> Pasta sauce jar

> Matches

> A hammer

> A screw (it should have been a nail, but what the heck).

> A tin tray

Stuff I had to buy:

> Meths

Step 2: Making it (the lucky way)

OK, admission time - I got lucky with this Instructable.

Jam Jar Jets are by no means my idea, and I knew very little about them:

Knock a hole in the lid of a jar, splash some meths in the jar, give it a shake and light the meths.

So that's what I did, and it worked first time.

After running for a short time, with a noise like an angry moped, the temperature got too high for the jar and it gave way.

That was expected.





Then I tried to repeat the thing...

Step 3: What goes wrong...


"Daddy, show us how you made the jet engine!"

"Not a problem", thinks I.

I grabbed another jar, smacked a hole in the lid, splashed in some meths and lit it.

Foosh, then nothing. It didn't work. (There's not much point watching past the first few seconds of this video.)



After some research, it turned out that the hole was too big. If you make a jam jar jet, and it goes foosh and then does nothing, like it does in the first video above, then the hole in the lid is too big. Go make another one.

(Later)

If your jet lights, goes foosh, and then goes RRRR for a moment, like it does in the second video, then your hole is not quite big enough.



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d_dmob8 months ago

Nice work.....

I would like to ask how many minutes does it take for the flight and how much distance covered with the fuel full?

Kiteman (author)  d_dmob8 months ago

I'm afraid that this doesn't actually fly, it lacks the thrust.

Running time varies, but is usually around a minute.

d_dmob Kiteman8 months ago

Thanks!!!

andrea biffi9 months ago

Do you think it will work with a bottle too? It could be an easy way to break the bottle after engraving a groove to make a glass, but it probably smashes...

Kiteman (author)  andrea biffi9 months ago

It depends on the bottle - if it has a short neck, it might.

Give it a try - the worst that could happen is that you make an alcohol lantern.

All right, I'll let you know :-)

manoo1 year ago
is alcohal fine
Kiteman (author)  manoo1 year ago
Whiskey, rum, vodka, pure alcohol should all work.

Beer, cider, they do not contain enough alcohol to burn.
manoo Kiteman1 year ago
how to make it
Kiteman (author)  manoo1 year ago
The alcohol? Ferment some, then distil it.

The jet? Scroll up...
manoo Kiteman1 year ago
how to make it
manoo1 year ago
how to make it
manoo1 year ago
how to make it
tobychan2 years ago
I drilled a hole in the cap of a 500ml Lucozade bottle around 8mm hole diameter. Then put in enough meths so that when you give it a shake, it just about coveres the inside of the bottle. I laid it on its side, put a flame to the hole and it went blasting off about 10 meters!
These engines were used in the V1 and V2 rockets by Germany. They would calculate fuel consumption and put exactly enough fuel in so that it ran out over London and the warhead would plummet down.
So what exactly is a Meth?
Kiteman (author)  lancealotx212 years ago
<em>Meths</em> is actually methylated spirits - please read the rest of the comments.
Kiteman (author)  lancealotx212 years ago
<em>Meths</em> is actually methylated spirits - please read the rest of the comments.
Could you use rubbing alcohol?
Kiteman (author)  Mythbuster Kid2 years ago
If it's flammable, then yes.
Thanks.
IronWill2 years ago
pretty cool, but I'm concerned about the potential glass shards being scattered IF it was to explode.
perhaps use a tin can or at least tape the glass container. so that it may break but not harm anyone.

nice guide though.
Kiteman (author)  IronWill2 years ago
They don't explode - the big hole in the top means they can't build up enough pressure to do that.

The reason they break is because the temperature differences across the thickness and height of the glass causes fatal fractures.
still not worth the risk too much meth is being used.
i am not saying your project is flawed, I'm giving a heads up to those new to it.
If you want safety, rub the bottom of the jar on the sidewalk and suspend the whole thing from a cord. That way the bottom will blow off without causing any frags.
Kiteman (author)  IronWill2 years ago
Hey, it's cool.

Everybody should assess their own risks, and if my project is too much for you, I'm not insulted.
boom man562 years ago
where did you git the Meths?
Kiteman (author)  boom man562 years ago
You'd need to ask your parents to buy it. See other comments for suppliers.
Have you tryed using this to propel a model rocket? ( Or other mode of transport?)
Kiteman (author)  The Dark Lord2 years ago
No - the burn cycle it very sensitive to symmetry, and tends to stop when you lay the jar on its side.

I do keep meaning to try adding an absorbent pad to hold fuel at the bottom of the jar to see if it works in its side then, so maybe you'd like to experiment for me?
I suspect that it is the air fuel mix that is killing it when you lay it on it's side. Try putting your hole near the top of the jar instead of the center and see if that works for you.
Kiteman (author)  BrianRandleas2 years ago
According to what I've read*, the burn needs to be symmetrical to be successful.



(* Which isn't much)
andy555514 years ago
is there a way so it doesn't brake at the end?
i keep mine water cooled and also wrapped the glass in duct tape so if it does break its easy to clean up without getting cut. you can also just drill a hole in a can of broth and just use that.
That was my thought on using a metal can as well. A beer can or soda can pierced from the bottom instead of "Popping the top" should work as well. If you can find a way to pull the bottom into a cone shape that should also give better results if your wanting even negligible thrust. If you are using a metal canister you should also be able to lay it on it's side. More important than the shape of the flame is the air to fuel mixture you are obtaining.
Kiteman (author)  andy555514 years ago
Some people recommend standing the jar in cold water, but I would like, one day, to make a metal version, maybe with water flowing round heat-transfer pipes...
Aldeas Kiteman3 years ago
Have you looked up the heller/lockwood version of the valveless pulsejet? That version uses a u shaped arrangement of the tube with and expanded combustion chamber to set up the harmaonic combustion pulse. one guy ran a gocart on one of these things using propane as a fuel.
BitBoink Aldeas2 years ago
Ya I remember SRL (Survival Research Laboratories) did a pulse cart back in the 90's. The pipe was glowing bright orange-hot right behind his head if I my memory serves well ... was insane looking!
or possibly have a undamaged lid freeze the jar with the meths inside and then swap lids? but then again it might get hot fast and break sooner
I haven't tried this specifically,
but just as a reference to something I have done, unintentionally,
Rap a jar containing a candle in a cold, wet rag. The glass breaks pretty quickly, large cracks, some shattering, the works. so i'd assume that cold liquids, of any kind, with hot glass is a no go. 
about to go try this with a beer can replacing the jar, thet way it cant smash and the hole is a pretty good size anyway.
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