Firing A Clear Vacuum Cannon & Testing Viewer Suggestions 

thanks for being a king of random without clickbait

Try using something like a paper cup for the valve. Just insert it into the pipe bottom side in so that it wedges itself in and holds the pressure when it's being pulled back. You can cut most of the cup off since you just need the wedge shape, and since it's light enough it'll just become part of the projectile like the aluminum did. Alternatively, if you can bring a small vacuum along and have a minor vacuum between the plug and piston going all the time, than you can use anything flat and light as the plug since the vacuum will hold it in place and you won't need the wedge shape. So you'd load the projectile, cover the face with a paper plate or a small piece of cardboard (for stiffness), and it'll be held there by the minor vacuum until you fire. If you're going to use a vacuum pump however, make sure you have a check valve in line so that the pressure doesn't shoot back into the pump. Third option is to get a female-female adapter pipe and just slide that over the aluminum sheets (instead of taping it around the edges each time).

That is pretty awesome! When I was a kid, I built a pressure cannon using a plastic tube, bicycle pump, and a projectile. When the pressure built up enough in the tube, it shot the projectile pretty high. Thank you for sharing.

This is the best DIY channel on RU-vid. No clickbait, just honest and detailed tutorials with great quality. Keep it up!!

I wonder if the mass of your flapper valve is part of the problem? The heavier it is the slower it will be to be pushed out of the way by the air pulse in front of the projectile.

You're an inspiration as always! I have three suggestions for easing the opening of the valve: 1. Make the actual flap part (or rather all that is moving) lighter so that less energy is required to move it. Just grinding of excess bolt and "skeletonize" the metal hinge should make a considerable difference. 2. Hold the valve assembly on with elastic bands to make any potential impact less destructive. 3. When the projectile hits the flap it soon engages with the bottom of it, giving it very little leverage, a pin either at the top of the flap or in the middle of the projectile that engages instead of the actual flap part should yield better leverage.

i made one large enough to fit myself into and smashing the burst membrane from inside, controlling the vacuum pump on the outside via my mobile. Using high explosives I normally suffer burns and lost toes but thanks to this man i arrived at my destination abroad completely and intact apart from a little brain damage, and burn-free.

Fantastically simple, yet so refined.

You can add a rubber band to the valve, and adjust the pivot point, so the closed position is very unstable. A small opening of the valve will cause it to slam fully open.

Need a Joerg Sprave patented rubber-powered valve release.

To make a lighter valve, get a sheet of silicone and a thin plastic disk. Much lighter than a furniture slider. You could easily keep the whole construction at a few grams

Thank you for not becoming a youtuber that cares only about the money. Most channels that used to make quality content now don't and became sellouts, but not you. Your content is actually getting better and better in my opinion. Great video and have a nice day.

I believe many people think of this but just don't say it because it seems obvious and like videos are supposed to be like that so there's nothing to go crazy about. I wanted to say that you make amazing videos, amazing projects and we see that you do put a lot of effort in your videos and projects and I wanted you to thank you for that and I hope you continue making these videos. you never disappointed me and I watched your videos from the beginning.

Original. High Quality. Wonderful content. Love this channel

I love that you really spend the time to explain the forces and other factors involved in your projects. Keep up the good work!

my favourite videos are the cigar box guitar videos, the long build process is super satisfying to watch

Sometimes the simplest things work the best

Please angle the valve! Then it will need to move out of the way less! You would need to alter the pipe, but I am very confident it will change your results!

I really like the idea of a reusable vacuum cannon and would suggest using a weak magnet for attaching the projectile to the pump. Also another suggestion would be to use very weak magnets for attaching the valve to the end of the vacuum cannon. I really hope my suggestions help you with this project and keep on making great videos. -Beau

Its awesome that you still read all of your comments!! Keep the awesome videos coming!!

Have you thought about making a smaller handheld version with the same technique?

I have an idea about how to open the valve. It's adding a secondary tiny cannon that opens the valve some miliseconds before the real proyectile came to the end of the barrel.

3 years later... Still one of the best videos, of one of the best educational conntent creators.

I've been here for a while. i stumbled upon your channel for aprox 6-7 years ago searching for fireworks on RU-vid. i watched alot of your content back then but i were only about 10 or 11 so i didnt think of subscribing. You popped up in my suggested feed not to long ago and im glad i found my way back. Your content is top notch, and i wish you all well with your youtube career

Very cool concept

You may be able to use a spring or several rubber bands to accelerate the flapper open faster than gravity can. I have made a simple diagram that I hope is understandable in how you might be capable of achieving a faster opening of the flapper. i.imgur.com/Or6Rrlu.png

This was the first Vacuum Cannon video I saw, and I immediately went to watch all the others, this is so cool. I'm gonna try to make one

Thanks for doing those experiments and sharing them with us! Idea: Wouldn't a spring-loaded flap do the job? I mean a powerful spring. But you would need some sort of latching mechanism. Thanks for reading this!

An awesome video as usual. By chance can you make the burst flap lighter, maybe using styrofoam. That way the air would require less force to move it faster.

This will probably also not work, but instead of one big valve at the end you could use... two half valves. Maybe if one half opens to the top and one to the bottom they need less time to tree the way for the projectile. Last but not least suggestion: Put some corn starch in the end of the tube, so it gets shot out by the projectile.

I was a subscriber years ago. about 6 years I think. WOW thing have gotten a lot better. old subscriber coming back.

I love the sound it makes when it fires.

So the issue seems to be you need to get the flap to open before the projectile gets too near it. The only suggestions I can think of might be too mechanically complex. You could borrow a technique from semi-automatic rifles that use the gas pressure from the barrel to operate the bolt., except in reverse. A separate gas tube that will use a piston (instead of a bullet) to open the valve as the air comes rushing in. A spring would also help, using the same "over-center" sort of arrangement you're using with gravity and the hinge, it wouldn't take much force to open the valve enough for considerable spring pressure (A rubber band mounted perpendicularly to the barrel) to yank the valve open quickly. Timing becomes a problem because since you're depending on the vacuum in the barrel to launch the projectile, you want that opening to come as late as possible. You'd need to use your high speed to figure out how long it takes for the valve to clear the barrel and how far from the end of the barrel the projectile has to be to give that time. The moment that valve opens, you lose any thrust because the vacuum is relieved. Frankly, you might just be better off with a faster way to make foil caps, say, making a bunch of collars that you can prepare in advance that fit over the end of the barrel.

Looking at the slow motion frame by frame, it looks like the flap maintains a constant (too slow) angular velocity after it loses its seal. Perhaps you could design a valve that is slightly recessed into the barrel and sealed with an o-ring like your piston. This might give the air pressure more time to accelerate the flap to the necessary speed to push it out of the way, instead of only pushing in the instant before it loses its seal.

Excellent! I have used your previous video in my science class to ask the kids to guess what would happen. This one would be very clear for them to see exactly what's going on. Thank you.

the slow mo cornstarch/smoke shots are interesting because they show a resonance of the air going in and out

awesome vids keep them up

thats a shame that you have 1.2mil subs but a little views

Been watching for years, love this guy’s content 👍🏼

I just love your voice. So soothing.

maybe you could get a faster valve with a mice trap like mechanism (spring loaded valve)

I didn't know Ted Cruz had such a smart brother

I'm sure we would all love more x-carve videos! Love your content! Keep up the great projects.

I have a pretty simple idea about your valve problem. Instead of making a mechanism that relies on that hinge you could use a magnet mounted to the tube just to hold the disk on with the least amount of force so when the air rushes back in it just pops the valve off as it travels along the tube.

Why even use a hinged valve? Soft rubber or silicone on a piece of aluminium should hold it to a well sanded pvc edge by itself and pulling the tube into vacuum will secure it in place, add a couple of feet of fishing line on the valve and to the barrel (or ground) to recover it. Hinge just adds extra weight & friction.

ich mag Züge...

You can also make a small device based on your coaxial piston design. Put a cap onto the outer pipe and drill a hold to accommodate a smaller pipe, maybe a half inch wide, to use as a barrel. Using the same centering technique from the coaxial cannon video, make sure it doesnt extend all the way past the length of the outer pipe. Then, modify the piston by drilling a hole at the top to create an airtight seal with the inner barrel and the outer casing. This way, when you pull it back, it will extend past the inner barrel and air will rush in creating a VIOLENT SUCKING MACHINE

I think these are gonna be my science project next year.

I like trains...

you should try to put a set of magnets in the piston/projectile to hold the projectile back when loading :)

Never stop being amazing. Never stop making us say "wow!! How did he think of that?!" Never stop making us excitedly show our other science nerd friends your videos. Never stop delivering smiles to all you reach.

1. A smaller pipe alongside, maybe with its own piston, with the end sealed against an extension of the flap. The air will travel faster as it doesn't need to push a projectile. Might be a little too fast, though. 2. An off-center spring that will accelerate the flap once it passes the equilibrium point. 3. An inset valve, so that it accelerates to greater speeds before losing the seal.

I recently started watching your channel and love it!!! Two problems with the cannon:A-Use same bent/set forward valve with a Vertical Spring/or L shape coming back under. B:-Use a Magnet or Electro-Magnet to hold the projectile... I guess winning the science fair in grade school paid off... Lol... Simple, yet effective. Hope it works for you. I think I'll build my own now too! Awesome videos you are great at this. If you use an Electro-Magnet, just use a small wire that disconnects just before the end of the pull or not depending on how powerfull it has to be... L8R. -Chad.

Cut the front end of the tube at a 30-40degree angle. Make an ovular valve to cover the opening. This way, the valve would have to travel a shorter distance to get out of the way of the projectile. Gravity would also assist the valve better this way. Use a string to hold the valve in place until the vacuum build up is enough to hold the valve, then let go off the string, then pull the piston further until release.

In my opinion, you should take advantage of the principle of energy conservation! Build a bullet that hermetically seals the top of the tube and has the same mass, or a slightly lower mass, than the bullet that collides behind! It should have a one-way valve inside to get out the compressed air just before the impact !! Do this test !!! ;)

One suggestion: it seems you would need additional mechanical spring type support to open the flapper. The key would probably be to engage it only at the end of the procedure when the pressure already built up. So maybe a string cut at length to coincide with the moment you are pulling the piston to engage the additional flapper spring right before you shoot.

Add a magnet to the front of the projectile and a magnet to the flap so that they repel. By experimenting with the size and strength of the magnets you could adjust the buffer between when the flap opens. If that doesn't work try adding a reed switch to the top of the cannon and putting a small magnet in your projectile. Make a spring loaded flap from a mouse trap and then connect a servo to your switch which will trigger the mouse trap when the projectile passes your switch.

Almunium work very well

one thing i'd love to see with this design is a miniturized "hand cannon" type version that can be shot while held with one hand. would be neat to see!

I'll never forget the awesome cheese ball machine gun. Nice job. -Douglas

Nice work--you could try using a very light material (like a carbon fiber disc) to seal the end, and you could also have a hinge that could move out as well as down--attach the hinge to a light rod that slides out of a tube connected to the cannon, for example.

A couple of suggestions. Put bumpers on the flaps made of rubber and where the flap hits the bottom of the cannon. Then install a push rod at the front of the projectile that pushes the door open this would then allow the door to be open and continue on. You could also make a second smaller gas tube that is tuned to push the flap open when you desire with a smaller projectile. Much like a gas tube on a semi-automatic runs the action of the pistol. Though this second one would be difficult.

You could try adding a spring or a rubber band to pull the valve down before the projectile hits it. You would need a latch to keep it close though. Also to make the barrel smoother you could try taping sandpaper to the projectile. It would likely make the inside cloudy but it would be hilarious to watch

Suggestion for the valve: Use a weight or a spring pulling vertically downward on the valve so that when the valve is closed the force is holding it closed, but when the valve moves beyond the tipping point the force is now pulling down on the valve. This might also keep the valve from bouncing back.

First of all, let me say that i love the videos and i think you're at least a borderline genius. With that said, here is what i think is happening. The hinge is a great idea, but it has an inherent flaw. In order for it to work, the flap has to move forward with the inrush of air, but it can't because the hinge actually inhibits the forward motion that it must have to get out of the way. The pressure exerted on the flap is equal all the way around the circumference of the pipe and it's trying to move it forward, but it can't move forward because of the hinge and the way it restricts movement at the bottom of the pipe. if the hinge were able to slide horizontally it would help it get out of the way, but this action would take time that probably isn't available. i say that only for those of you that haven't tinkered with these. Instantaneous is not a good word for it. When the vacuum releases, it happens so fast it's mind boggling. The videos are great, but they really don't do justice to how incredibly fast the action is. My only suggestions would be to try something that doesn't seal quite as well inside the barrel, so a little air can go around it and help push the flap out of the way before it gets to the end of the pipe, try something a little heavier, or a combination of both with a slightly longer barrel. Keep up the good work Sir. There is at least one old fogy out here that enjoys them immensely.

Great please keep doing your efforts are help full to many others who can not do such things it makes them more creative I am syed sami haider an incharge of ATL a creative lab which is helping school students.

One of the things I've become interested in lately is water rockets. There's a lot you can do with them, including 2 stage rockets. I'm not really into rocketry but there is something different with using water as propulsion for me. Might be a cool idea to check out

You could add a secondary, small chamber that pulls a vacuum at the same time, but have this secondary chamber slightly shorter in length than the firing tube, so that the air rushes in right before the projectile barrel. This secondary tube could be a much smaller diameter, and would be used to open the valve of the larger firing tube. Another idea; use cutouts of plastic that you can just place onto the end of the barrel, possibly with some sugru applied at the end of the barrel to make a better seal (look at TKOR's video on homemade sugru). This plastic piece would have no hinge, you could either just leave it be and have it shoot off with the projectile, or attach it to the end of the firing barrel with a piece of string so it doesn't fly away every time. An alternative of the above idea would be to dangle the plastic seal via a string (or 2 for stability) above the cannon, in such a way that it can easily be pushed away by the projectile, flinging it upward and around, constricted by the length of the string A final idea, unrelated. Try to put a thick piece of rubber, like multiple balloons on the end of the barrel. try to find a rubber, maybe spandex, that you could just stretch around the barrel, and possibly aid in holding it with a pvc sleeve that slides over it. I would like to see how much the rubber is pushed in to the vacuum by the normal atmosphere, which leads to the final idea. Get a thick, maybe 6 inch inner diameter piece of acrylic tube, and place a seal on one end for pressurizing. Mount the vacuum cannon tube inside it, maybe with multiple filed out bushings to center it inside the acrylic (or use acrylic for both tubes). The end cap on the outside tube would have two valves on it. The inside tube would be connected to one of these two valves. Use a screw on end cap if possible for ease. Pull a vacuum in the inside tube, and pressurize the outside tube. You end up with a vacuum cannon inside a pressurized tube, in such a way that the projectile makes it out of both tubes. I will send this to your email, along with a diagram I drew in order to visualize it.

Have you experimented with using the end cap AS the projectile? For instance place a wider cup around the muzzle so that the original barrel forms a lip inside and then fix a rubber O ring to rest on the lip or the rim of the original barrel. By placing a projectile over the mouth of the barrel within the cup extension the projectile should act as a plug against the O ring when the shaft is pulled back. I am unsure how this would preform in actuality and I have a sneaking suspicion that the trajectory may be less than impressive but it could be worth the experimentation.

Thanks dude. Flap valve looks better now

Run a small spring along the outside of the latch, over the hinge. Keep the latch extended so when it is in the closed position so it acts like the cam on a compound bow. Yeah, just a simple spring elliptical cam. The little bit of air would flip it enough to push it past the crux of the ellipse and the spring would pull it down and out of the way.

Add a little rubberband assist to the valve that gets tensioned about halfway into the draw by a wire attached to the grip section. If enough negative pressure is built up before the valve opener is tensioned it should stay closed until release.

i like your videos, keep up the great work)) and i like how you're not as commercial as most other youtubers.

if you make a spring/rubberband loaded valve and attatch a string to it to close the valve while pulling the piston back, it should work fine.

If you link the valve with a spring to the piston, such that the valve is being pulled open by the spring when the piston is pulled back, but isn't having any force applied when the piston is all the way forward, the spring will help open the valve faster, and you'll still retain the property of the valve staying closed on it's own. You could even tie some string between the valve and the piston handle, and loop it through a weight. If you set it up so the weight is resting on the ground when you're all the way forward, but is lifted when you pull it back, the weight will assist in opening the valve

I like your videos and apreciate all the work you put into them!

I suggest having some rubber bands aiding the release of the valve. Have the rubber be in front of the hinge fro the most of it's position, but just pass the hinge when you close it, that way it will hold the valve against the tube, but a light nudge will send it flying. Essentialy same as gravity, just faster and stronger.

Great Video as always! I'd love to see more Coaxial Cannons!!

I really enjoyed the smoke shot

1. reduce the mass of the valve (foil, reinforced with a plastic "spider web"?) 2. Add rubber bands to assist the fall of the valve. A force vector acting in the direction of gravity would help

what you could do is attach a magnet to the back end of the cap and the front of the projectile. so it stays on before you draw the piston back and once you do the vacuum will keep it closed till it fires. eliminating the need for a hinge.

By upscaling this design, the present air will be able to reach the front faster, leaving more time for the valve to open. You would need to calculate the time it takes for the flap to open, and lengthen the pipe accordingly. You may need to allow more air initially. We obviously need a 50' vacuum cannon anyway.

Thanks for braving the smoke!

Suggestion for the flapper valve: You need to make a spring loaded valve with a good deal of spring force to pull it open. You could make a simple latching device that would lock it into place before pulling the vacuum. The latch could be released by a small vacuum piston that is connected to a hose and tapped into the barrel a few inches from the muzzle. That way, you can load the barrel and click the valve closed and it will stay closed even though a large spring is trying to snap it open. As you draw the plunger back, the plunger creates a vacuum in the barrel and when you pass the point where the hose is tapped in, the vacuum is transferred to the small hose and it pulls the release on the valve so that it is no longer latched. Now the vacuum is all that is holding the valve shut. When you fire the gun the valve should move very rapidly open when the vacuum is removed.

u are one of my favorite utuber and I do like those air gun vids

Maybe add a spring loaded assist, to speed up the flap & make the flap lighter in weight ? Entertaining video 👍 ✌️

subbed due to simple and interesting video's without the hype! well done

Hmm, what about a flap valve made from leather, reinforced on the back with a metal disc? The projectile will still hit it, but it should be much more durable. Another idea is to cut the muzzle end of the barrel at an angle, and have an elliptical flap valve- the projectile won't be smacking into it so hard since the shallower contact angle makes more a softer impact... in theory...

you do a great job with your videos mate keep them coming

Idea #2. Keep the same setup, add another hinge about 1 foot down the barrel, so that that the disc now also drops down, instead of having to rotate so much. It will still rotate a little on the original hinge, but as soon as it is no longer stuck to the end by vacuum, it will also start to fall as it rotates.

You could try adding a spring to the valve hinge so it opens quicker. Of course you'd also need a latch to hold the valve up until you prime the cannon. You could also add a simple ratcheting mechanism to the piston so you can leave it primed without having to keep pressure on the handle. It wouldn't be too complicated to set up, and it would make the firing process a little easier. Another advantage is you can hold the spring valve on with whatever latch you want and then remove the latch once the cannon is primed.

Cut a groove for an o ring into the projectile and glue an object inside of the tube, stopping the projectile from moving backwards.The projectile becomes the pressure seal.

if the flapper is a must.. then lower the center of gravity and shave weight till it almost fails for a better moment o.e. ( lower bolt instead of being in center of flapper lid..and remove a lot more metal from upper half of flapper hinge for weight loss) awsome video.

You could use a dremel to make notches in the projectile to help the vinyl tube grip the projectile slightly tighter, and you could put some kind of metal plastic or rubber spring on the front which would cushion the impact with the valve somewhat so that the valve was not impacted directly by the projectile its self which might then allow the valve to be reused, although depending on the length, shape and potential whipping action it might cause the projectile to tumble. Also perhaps a tiny balloon on the front which would deliver some push and cushion but would explode in such a way that it did not contribute any rotational force to the projectile.

If yu intend to keep your vacuum seal on a hinge mechanism, maybe drilling a small pinhole(s) in the projectile face would work. This will leak air forward of the projectile and open the cap ahead of it. This assumes leaking air will travel faster than the projectile. Also not as efficient as the aluminum foil seal, but the engineering design will provide faster repeatable shots. Optimizing the pinhole size will take some experimentation I imagine. Great work!

I appreciate your videos. Look forward to your next one. Build on.

I love that design

I would try going back to the upward hinge but put a slightly tight spring on it to pull the flap up. But then youve got the plastic cup idea thats already functioning. Great build either way

I think you are on the right track with the design of the flapper valve you have now, but try maybe switching to lighter materials. Maybe it's that there is too much mass there, that the air in front of the projectile has to move. So, try to find a thinner rubber seal and one too that's closer to the ID and OD of you barrel, thinner and lighter seal backer and a lighter hinge. Also, instead of using a steel screw to fasten to seal onto the hinge, it may not be strong enough, but you could try using a plastic screw and nut. Or even try an aluminum rivet as an alternative. Hope this helps and good luck!

You might try a valve design that I used for one of my blowguns....you will need to cut your barrel's muzzle at a bias off the bottom ( at least 45 degrees) and make a valve cover to fit the new elliptical shape. What this accomplishes is it reduces the number of degrees movement to "fully open" by half, so the valve is out of the way twice as fast. It's kind of like being half open already when it is fully closed. Some sort of spring-assist for the valve wouldn't hurt, either. Place the vector for the spring's movement such that it barely holds the valve closed, but after only a few degrees of movement it wants to jerk it open! Well, that's MY two cents....love your V-Cannon, man!