I remember the supersonic ping pong ball from mythbusters, they found out that air that push the ping pong ball always managed to go around the ball through the tiny gap between the ball and the barrel. So at some point, the length of the barrel will no longer add speed, and even worse in vacuum canon, since some of the escaped air will actually act as cushion and prevented the ball to go through the other end.

I've been making these for years but it's really funny how I just got done making mine again last night and it worked perfectly and then this showed up in my feed this morning

I'm pretty excited for part two!

Just impatiently waiting for part two :D Nice demos!!

Fabulous Bruce ! Wonderful video! Thank You! Looking forward to part 2 🙏☺️

It’s great to see you doing well Mr. Yeany!!

Really great stuff once again! Another entry in my long list of stuff that I want to build...

Thank you for sharing your knowledge. I was just looking for something for a project I am doing that I know will work. Now, not only do I know it will work but, I also know how and why. Much appreciation!!

That was amazing, I never heard of Vacuum Cannon before, and now I think I know why cannons have a long tube (called barrel I think). can't wait for part 2 Thanks

Honestly you're much better than Steve Spangler. He might have a bit of showmanship but you have the skills, knowledge and can interestingly tell what you're doing. Keep it up Bruce!

Superb Robert.

I've wanted to make one of these since I saw the episode on myth busters. These videos gave me the motivation to go ahead and do it. I've had a bit of trouble with cheap mylar balloons failing prematurely so I've switched to the slightly thicker mylar used in some snack food bags. (pirate's booty is the junk food of choice around here) I have a 5 ft tube and so far have been able to get to about 250 mph. I plan to try a few other types of balloons as I think the thicker mylar may be slowing me down. Thanks for the idea! I really enjoyed the videos!

I just made the vacuum cannon for my physics class. They loved it. It will make ballistic pendulums a lot more exciting next year. Thanks for the video and the idea.

I take it back, you are NOT MacGyver, you are Rambo!!!!!!!!!!!!!! LOL. Stay safe and healthy.

Excellent video again

Awesome!!

Noticed at the 12:12 mark when the combined vacuum and compressed air cannon fires you can see some sort of oscillation at the end of the barrel where it appears as if the gasses were attempting to equalize by rapidly flowing in then out then into the barrel end. I hope we get an explanation for that in part 2.

Nice work, thank you. Have you tried anything heavier than a ping pong ball?

The most interesting would be to see what materials and weight will get the furthest ! And how this is calculated !

Most entertaining!

Very cool 👍

Well done

I was gonna comment that you should vacuum tube the the barrel of the pressure cannon but you granted my wish! Also, another reason bit might slower is due to the need to accelerate air already in the barrel of the pressure cannon. With vacuum cannon you have no such resistance.

Awesome

In the pressure cannon, the air in front (target side) of the ball must be accelerated in order to get out of the way of the ball. Air is heavy. The air inside an ordinary refrigerator weighs about 1 kg or 2 lbs. The longer the barrel, the more air must be accelerated so that the ball gets a smaller proportion of the total energy.

I remember this on Mythbusters :)

I made the vacuum cannon and am having trouble getting the ball to exit. Mythbusters used regular packing tape to seal the ends, so I am as well, but the ping pong ball only exits every 3 or so shots. Other times it seems to hit a cushion of air and stop before the end. The ball is almost an exact fit for the pipe, so not much air is getting around, but I still can't get anywhere near the speeds in this video, and that's if it fires out at all.

Legend!

I demonstrated a vacuum cannon at work once. Just the noise from the implosion was enough to make people jump out of their seats.

You are missing the upper level where the compressed air cannon is coupled to the vacuum cannon

I imagine the compressed air cannon would benefit from a sort of scupper valve once the barrel length gets long enough. I would rework that ball valve so it can easily snap open, or exchange it for a fast acting butterfly valve.

Terrific video, I have one of these in my office! Why doesn’t the 126 inch barrel have more velocity than the 108 inch?

Bruce, I'm joining your team when the apocalypse happens.

You know what's really funny I just got done making my own 2-meter long ping pong vacuum device as well

Hi another great video

Imagine combining both...

"Honey, Im going back to the store for beer... i mean science"

I've seen both combined.results where a wee bit on the stout side

I did a thing and physics girl: "I've seen this before"

Cool

I wish that I had the time to build this for my students

you should combine both of the canons by trasphering all the air from the barrel into a airtank behind a valve to add even more pressure difference between the ball

I wonder if you could run them in tandem to get even faster balls.

You need some PLC's for the valve on your compressed air cannon. I know its just for demonstration but lets crank this baby up to 11!

briliant as always. thanks for the vid.

the more barrel you add to the compressed air cannon the more air the ball has to push out of the way, correct ?

A projectile hole is always the same shape. Can you tell us anything about that Brucey? Whether it's an airgun through glass or a ball through a window always the same keyhole looking shape. I even once saw a pigeon fly into and crash through a window and the hole was the same shape. A keyhole looking shape....

Would a better sized projectile perform better? Something closer to the ID of the pipe to create a better seal?

Hmm. An interesting concept to use on large scale weapons. A vacuum sealed barrel.

Attach the vacuum cannon on the tip of the air cannon so you can have lots of pressure in the back and no resistance in the front. :)

Incrível

So theoretically, the max velocity of the vac pump would be the speed of sound ?

If we put a plane figure at the end of the tube, can it make a sonic boom ? 🤔

Very nice, but don't waste food it is very precious.

At the very end of the video, watch the end of the tube. You can see it “breathing” as the pressure tries to equalize with the atmosphere.

make a hole in the ball and fill it with sand...this will give some mass so it can reach crazy speeds and distances

What happen if we combined both vacuum and the compress air cannon?

Physics girl was able to barely measure the output velocity of the vaccum cannon, allowing us to combine it with your video to compare it.... But the one thing I find interesting is that a certified physicist did not think of speed stops while a science teacher did, allowing for better scientific results. And that a can crushes while a tennis ball absorbs the hit so well.

Wat would happen if i put my hand in front

Shoot the ball with the pressure cannon through the vacuum cannon.

Sir there is a you tube channel called Smarter everyday. He does altra slow motion and is also holds degree in aerospace engineering. I think he will be glad to film it for us. Meanwhile can you please tell us some home science projects during covid lockdown. Thanks and stay safe.

So do rockets work in the so called infinite vacuum of space, with such thin walled aircraft as we were told?

10:23 That's alot of damage

Are those ping pong balls nitrocellulose? Don't just throw away the scraps. :)

Hi! I’m the ping-pong police 🚔 and I say you cannot do that to our balls

12:08 air seems to 'bounce' in and out of the barrel...?!

"ONLY 100 ft." :)

3:45 Dear Bruce, I am from Germany and know none of these units even thou I studied computer science here and speak several languages. Please also add metric units to your videos since most people on the planet are used to them. :-)

NightHawkInLight has an excellent series of videos exploring both vacuum and air cannons. It's worth checking out his stuff if this interests you.