Guys, today we're taking a look at how to build
a very simple tennis ball cannon
made almost entirely out of soup cans.
[Captions by Judy V. at Y Translator] [Music]
We'll show you how to construct the CANnon...
Get it?
Can-- It's not that funny.
And then, we'll try out a few different types of fuel
to see what works best.
All we need to get started is eight or nine cans,
a little bit of electrical tape,
and of course, a can opener.
Here's the basic idea.
Several of these cans lined up together will create a chamber,
where pressure can be built up when our fuel explodes.
A tennis ball suspended about halfway down the barrel
will be launched out the front, flying up to 100 feet.
Of course, you need to get cans that are the right size.
The tennis ball should be able to fit down in,
but not have a lot of extra space on the sides.
More importantly though, is that a lot of cans nowadays
have a modified bottom that's designed to make stacking the cans easier.
While the modified shape of the bottom does make it a lot easier to stack the cans,
it makes it harder to open the bottom with a can opener.
So, what you're looking for is a can that's the same
on the top and the bottom.
If you go through cans regularly, you can just save them up as you use them.
[Music]
Our last two cans, let's cut off the tops,
but not the bottoms.
With one of these two cans, we'll leave the bottom fully attached.
With the other one, we want to do a special cutting job
where we leave two connection points,
one sort of at the top, and one at the bottom.
Then we're going to try and fold that bottom in on itself,
so it can act as a support that still lets a lot of air through.
With the last can, we'll leave the bottom attached,
but let's drill a small hole into it.
[Music]
After rinsing and drying all of our cans,
it's now time to attach them together.
The one with the hole in the bottom is the bottom of our cannon,
and the support should go a little over halfway up the cannon.
Now, using some electrical tape,
we're tightly going to wrap a couple of layers
around the seam where two cans meet.
[Music]
I like to make the folded support at the top of the fifth can.
That way there are four cans above the tennis ball,
and five below.
Nine soup cans taped together is giving us a pretty good barrel,
and our tennis ball rests right at the bottom of the fourth can.
Let's give this bad boy a little bit of decoration
so it doesn't just look like a bunch of cans taped together.
[Music]
Our soup can cannon is now all constructed.
Hello.
Let's see if we can't fire tennis ball out of this bad boy.
When I first started researching this project,
I was told that the best fuel to use is Zippo lighter fluid,
although I've had some problems getting it to work consistently.
So, let's give it a few tries, and then if that doesn't work,
well, we might move on to something else.
Now, the fuel itself is just going to burn if we light it on fire.
So, the goal is to get it to spread out inside the cans,
and then just start evaporating
so, we have fuel fumes filling the chamber
at hopefully just the right ratios that a flame near the hole at the back
will ignite all of it,
and will create a lot of pressure launching our tennis ball out of front.
[Music]
I'm gonna use my little torch.
Any barbecue lighter or regular lighter,
even a match should work just as well.
I'm not going to be pushing the flame inside the cannon,
I'm just going to try and ignite out the back.
[Music]
So, the Zippo lighter fluid maybe can work really well,
and I just don't know the right secret.
There's probably just the right amount of fuel,
just the right way to spread it around,
and just the right amount of time to wait as it turns into fumes.
I think I have an idea for something that will work a little bit simpler.
This is methanol,
and I've done some experiments with it before,
and discovered that it is pretty good at igniting
almost no matter what the mix ratio is.
So, I'm just going to try putting about a capful of this
down into our cannon, we'll see how that works.
[Music]
Well, we got better distance.
The ball actually left the cannon that time,
although not very quickly.
[Music]
That sounded pretty good.
[Music]
Using the methanol, we're getting pretty decent distance.
The balls are launching 40 or 50 feet,
but I think we can do better.
You can see that the balls in these cans are not a perfect fit.
This is the closest size of cans that I was able to find.
If somewhere near you sells a can that holds the tennis ball
even better than that,
you're almost certain to get a lot more distance.
Since we don't have cans that size,
I have two different stop-gap measures we're going to take
to sort of improvised shrinking these cans down.
First, let's try just using a wad of paper towels,
and pushing that down into the barrel.
That should completely closed off all of the air supply,
and we should get a lot more pressure in the chamber,
throwing the tennis ball out a lot harder.
[Music]
Ah, yeah.
Using paper towels as wadding clearly works pretty well.
The other thing we want to try is restricting the barrel down
to a slightly smaller size.
This sheet of craft foam is about a dollar,
and when cut to the right size,
should provide several successful high-powered launches.
The inside of the cans that I'm using have an 8 and 1/2 inch radius.
So, I've cut my sheet to 8 and 1/2 inches,
and now will fit this down as a tube inside the cannon.
You can see that the foam nicely fills the gaps around the tennis ball,
and now it just barely fits in.
Let's add a little bit of fuel,
and see how much of a difference the foam makes.
[Music]
It makes a difference.
It makes a huge difference.
Oh my gosh.
>> Where did it go?
>> It hit the tree about 40 feet up and bounced.
Oh my gosh.
[Music]
Boom!
[Music]
That is a cannon.
The heat seems to have warped the foam by just a little bit,
but I'm pretty sure we can still get some more shots out of it.
[Music]
Remember to check your local laws and ordinances
before building and using something like this.
Depending on where you live, it may not be legal to fire one.
And of course, always be sure you're doing it in a safe environment,
and make sure you're not pointing the barrel
at anything that could ever break or be injured.
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Talk to you then.