Firing A Clear Vacuum Cannon & Testing Viewer Suggestions
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- เผยแพร่เมื่อ 26 ก.ย. 2024
- In this video I fire a new vacuum cannon made from clear PVC pipe and test a few of your ideas from my previous video. Check out my Patreon page and please support my videos if you can! / nighthawkprojects
Special thanks to my top Patrons! Syniurge, Matthew Leitzke, & TheBackyardScientist!
This cannon makes use of my PVC piston made in an earlier video: • How To Make PVC Piston...
Here are my previous vacuum cannon videos if you missed them:
Building A Piston Actuated Vacuum Cannon: • New Vacuum Cannon Desi...
Building A 4" Bore Vacuum Cannon: • How to Make a Large Bo...
And my very first vacuum cannon video from many years ago: • How to Make a Vacuum C...
Thanks for watching!
thanks for being a king of random without clickbait
The problem isn't the click bait, but the weak content.
With the caps and emojis and no DIY, just "experiments."
YES.
A.H.W.
rocknexus king of random is click bait his channel went to shit
That what happens to TH-camrs when they care more about the money than the content
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.
It's quite light, I don't think it could be made any lighter while remaining strong enough to work. I used a lighter hinge and smaller attachment bolt for the valve in this video than my last one.
NightHawkInLight you should make a bypass pipe that lets some air around the projectile to open the door
That's actually not a bad idea at all. A cork would work well, though the projectile would almost certainly hit it from time to time
I guess that the one way to fix it is by making another smaller pipe that would be opened faster than bigger one, and helped the bigger opens little bit faster.
NightHawkInLight for sure the lighter flap would help!! maybe a carbonfiber disk with the PTFE would work and for the hing make it as minimal as possible! 2 wires epoxed to the disc and threw some I hooks!
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).
A cup is a really good idea! I think maybe a smooth plastic cup would work well. I'll try it
My concern with the plastic cup was that it's going to be much thinner than a paper cup (since you can make thinner plastic), and it might be more likely to crumple under the vacuum. Also, if you're going to try the route of breaking through the plug, maybe consider making the projectile more pointed so that it cuts through the plug easier.
The way to do it would be to put the plastic cup bottom first into the pipe like a cork. The plastic cups I'm thinking of I don't think will have any trouble standing the pressure in that configuration. Whether they move out of the way or not they will be easier than making burst discs. I will try it.
+NightHawkInLight , The bottom of an aluminum can is almost as light, but much stronger, due to the radial corrugation. You just need to find an aluminum can larger than the diameter or your PVC tube to cork it up.
NightHawkInLight you need to make a barrel that will reduce its diameter during charging and increase during a shot
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.
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.
This is the best DIY channel on TH-cam. No clickbait, just honest and detailed tutorials with great quality. Keep it up!!
Need a Joerg Sprave patented rubber-powered valve release.
that is both true and hilarious!
Daniel Forsman
BUT...
*"We must double up the rubber!!!"*
*"HA HA HA!!!"*
That's what I was gonna say. Might be difficult though.
Need a collab
Joerg doesn't patent any of his inventions
I love that you really spend the time to explain the forces and other factors involved in your projects. Keep up the good work!
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.
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.
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.
I actually thought the same. I think the problem is that the liitle amount of air inside the chamber Knocks the valve then the air escapes and the only thing pushing down the valve is gravity which is not ideal because the valve makes something like a circular motion and it takes even more time to fully open. So a rubber band in a position that when the inside air kicks the valve a little bit then the rubber band takes action and clears the bore. Maybe it wont work as well but i think its worth it
3 years later... Still one of the best videos, of one of the best educational conntent creators.
Original. High Quality. Wonderful content. Love this channel
I'll become a patreon soon :)
Fantastically simple, yet so refined.
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!
Sounds like a good idea. This does mean there will be a need to keep it closed while creating the vacuum.
Create more of a cap! Have a lip around the edge for some friction
It will need to be a balance between friction and easy release, but I think it can be done
Brett Coryell true it would add more mass to get moving, but I am hoping after seeing the slow motion footage that have the valve angles at 35 or 45 degrees will be enough to overcome both the added mass and problem of getting out of the projectiles path
Brett Coryell I think it could work, but the only issue is a little bit of back and forth. He had said that he could hold the cap closed with a piece of string, but that just adds another element to time correctly. I am sure if he can create a trigger system like you explained that it would be easier to fire, but how complex do you want something like this to get? It would probably work, but it is a little complex
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.
Sometimes the simplest things work the best
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?
Julius P vacuum would be too weak
I have but I haven't tested it yet. The shorter the barrel gets the weaker it will be, but I think it should still work down to 3' long or so.
I guess most people here would prefer a version that needs a car to pull back the piston. :P
NightHawkInLight that was my thoughts too, but what if the ammunition was .177 pellets in a 3 feet pipe?
Maybe you could have a longer barrel or a manual vacum pump
my favourite videos are the cigar box guitar videos, the long build process is super satisfying to watch
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.
I've been here for a while. i stumbled upon your channel for aprox 6-7 years ago searching for fireworks on TH-cam. 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
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.
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.
I love hearing about my videos being used for such things, thank you!
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
I agree - this was the same thought I had while watching the vid. It's usually called an 'over-center' spring mechanism. The spring stretches just barely over center of the pivot, then will accelerate faster that gravity can pull it down once the air pressure gets it started. It's a great mechanism also used on a lot of latches. It may take a little bit of tuning to get the geometry just right.
I had two other thoughts - one was to reduce the mass of the valve, but it still needs to be strong enough to resist ambient pressure. The other idea was to split the valve in half so it swings open from either side. The down side is you need two hinges, and a more complicated seal in the middle.
This is a fantastic idea
ejler thomsen You could have a cone shaped valve that opens up like a flower into several triangles, that way if it does get hit it will slide and open.
Thats pretty much exactly what I suggested in the last vdeo, but your diagram is far superior to my clumsy explanation.
ejler thomsen yeah that would honestly work! wow
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
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.
I agree, an inset valve might be what's needed
NightHawkInLight what if you had a small piece of maybe cardboard plugging the end, the vacuum could keep the cardboard stuck to the tube, but when the pressure increases between the projectile and valve, the cardboard loses all adhesion to the pipe, letting it fall away. Plus, if the projectile hit it, it probably wouldn't affect its trajectory/velocity, since the cardboard would have very low mass, and as such, very low inertia to overcome.
Not too sure, a valve that's inside the pipe sits tighter, and will probably be heavier.
However omitting the hinge will help to some degree; and if there is some (light) piece glued to the valve that's inside the pipe to hold it you won't need a hinge. And if that piece inside the barrel is making a pour seal it won't have much friction with the walls, but it will give the piece a chance to accelerate more. _(you that you would still use that same disk for holding the actual vacuum seal)_
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@all the engineers: because of the hinge the valve needs to *get both Angular velocity and horizontal velocity,* so it needs to *overcome both* angular inertia and linear inertia. (MV² + *Iω²)* That's one reason why the hinge is slowing it down. Then consider the fact the hinge is made out of metal, adding mass, and adding inertia. And then the hinge is not designed for fast opening with minimal friction, I mean nobody opens their funiture doors with the speed of sound.
Another (minor) reason is that once the valve has opened by a little bit, it's at an angle, somewhat working as a ramp redirecting the air in stead of being pushed away by it.
I'm thinking a lower mass convex seal (think half a ping pong ball) with an over center spring (or rubber band) in the same direction as gravity. Only a little force to push it past the pivot, but then it should snap down really fast.
I was a subscriber years ago. about 6 years I think.
WOW thing have gotten a lot better.
old subscriber coming back.
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 had a similar idea, but the half flaps would need to open from the sides instead of top and bottom. Otherwise gravity would help the bottom flap and hinder the top. If the projectile hits the flaps, it needs to hit both at once to prevent deflection and reduce damage.
It's a very good idea because the moment of inerzia decrease, the only doubt is about the sealing...
Thadox maybe a half sphere cut in halves could do the job.
c muller no, because if you use a half of a sphere, the center of mass is over the end of the cannon further than it is in the video, moreover the moment of inertia increase, so it's difficult to make it rotate around its axis, as a result it takes more time to open.
in front of a candle!
I'm sure we would all love more x-carve videos! Love your content! Keep up the great projects.
thats a shame that you have 1.2mil subs but a little views
Arvīds Gills dudes a freakin weirdo that's why
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
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.
Dr. Mauser I thought about this, too. Good one!
The trick would be to tap the barrel in two places. Say, for starters, one place near the front of the barrel, and one about halfway, each connected to the ends of a tube. The tube would have a piston in it that emerged from the front and could hit an extension on the flap hinge. The timing would be controlled by where in the barrel the rear tap was. In operation, when you pull back the plunger, the piston sees vacuum at both ends. When the projectile is released, it passes the rear tap, opening it to air pressure, while the front of the piston still sees vacuum, which pulls the piston forward, popping the flap. Then the over-center spring/rubber band takes over pulling it out of the way.
However, thinking it through, there are issues. The volume of the upper tube contributes to the amount of air in front of the projectile, So the piston needs to fill it, so there's little volume. but it also needs to be strong enough to pop the flap open against the vacuum in the barrel, which suggests a large diameter. Also, if the piston doesn't seal the tube, Air would leak through into the vacuum side as the plunger was withdrawn. Also, while withdrawing the piston you'd have the same situation of vacuum up front and atmosphere in the back, which would pop the flap as you were trying to draw. So making it work properly would be complex. Way beyond the scope of this kind of fun project.
Ooh! You just gave me an idea.
An over center spring/rubber band holds the valve closed (just like gravity) once there is a vacuum a small cylinder tips the bottom of the spring past the pivot (limited by an adjustable stop) so that when the projectile is hurtling towards it, and the vacuum is dropping, the spring will open it just before the small puff of air hits it. The stop adjusts the timing so the spring has just enough time to yank it out of the way.
It's only a little more complicated than the current version and it won't leak the vacuum.
What do you think?
I love the sound it makes when it fires.
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
maybe you could get a faster valve with a mice trap like mechanism (spring loaded valve)
Something I've suggested before. The problem with that is just that it gets complicated to trigger since those mechanisms usually require direct contact to actuate.
Likely the only way to get that to work requires electronics with an optical interupt sensor placed near the end of the pipe to detect the projectile passing by and then release the spring within a *very* short time.
I had the same idea while watching. I was thinking about how rocket hold down clamps are quickly released right before liftoff. Something like the bimetallic jumping disks, a snap spring that would hold in the vacuum, then the pressure of the projectile would make it snap back against the lid to kick it off.
CatSay how about a piece of string that is a bit longer than the piston, so that it pulls the valve down just as the piston is pulled out of the barrel? extend the hinge part that valve is attached to, tie the string on the end of that and tie the string on to the piston handle.
You don't actually need a trigger. The "moving of the pivot" trick works with springs, too.
I was thinking the same thing!
the slow mo cornstarch/smoke shots are interesting because they show a resonance of the air going in and out
Very cool concept
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.
awesome vids keep them up
I just love your voice. So soothing.
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.
Connected near the ground so it will swing out of the way, like an inverted pendulum.
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!
I like trains...
bird on a rock because i can 😉 and everybody has to know that I like trains 😂😂😂😂
Мне тоже нравятся поезда.
Been watching for years, love this guy’s content 👍🏼
ich mag Züge...
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.
you should try to put a set of magnets in the piston/projectile to hold the projectile back when loading :)
I think these are gonna be my science project next year.
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 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!
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.
I'll never forget the awesome cheese ball machine gun. Nice job. -Douglas
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.
I thought about this a bit more and it's a big challenge. Theoretically without an air cushion (some air remaining in the pipe) the flapper stays against a vacuum till the last moment - when it's hit by the projectile. Another wild addition to the spring idea above would be to add additional little pipe over the main pipe and near the flapper. The purpose of the additional pipe would be to equalize the pressure just before the flapper (one inch from the end -
first entry) when the projectile moves close the flapper (let's say 10 inches from end - second entry).
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
Ha, yeah not so sure about that sandpaper idea
I was thinking of spring loading it, small piece of tape to keep it closed and once ready to fire, pull a small piece of string to remove the tape then fire
NightHawkInLight You can use a magnet in the end of the piston and a external magnet on one side attached by string to the valve. This way when the piston is at the end of the barrel, you can push the spring loaded valve in place and use the magnet to keep it there temporarily. Once the valve is pulled back there should be enough pressure to hold the valve in place and at the same time the magnets will separate and the external one will fall to the side, out of the way of the impending destruction coming out of the barrel lol
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 like your videos, keep up the great work))
and i like how you're not as commercial as most other youtubers.
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 !!! ;)
Interesting idea, you're the first to suggest it. I'll have to think about that one.
If the bullet at the top of the tube splits, use the one-way valve as a pneumatic shock absorber !! Make sure that the flow of air out of the valve can be varied!
Could'nt the valve be spring loaded to assist a speedy opening once it starts to open just a little? also though sealing may be a little difficult, cutting the valve into two semicircles would halve the distance needed for the valve to get out of the way.
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
I like your videos and apreciate all the work you put into them!
An amazingly calming video (I guess it's thanks to your voice and the music :D ) Always hyped when I see an upload! I definitely consider becoming a patreon, 'cause it's in my head for some while already! I think it's about time now :)
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.
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.
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.
Your facial hair is Godlike, I mean literally like Neptune
Thanks dude. Flap valve looks better now
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.
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.
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.
Rewatching your entire channel again and I just love these videos man, you're so good at it
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
Almunium work very well
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.
u are one of my favorite utuber and I do like those air gun vids
I really enjoyed the smoke shot
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.
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.
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
3:34 That cannon flap can probably trick a football better than I can
you do a great job with your videos mate keep them coming
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.
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 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.
You don't upload enough to make me want to support you on Patreon. Upload more often and I'll definitely throw some cash your way!
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.
Springs and bands can also be made so they would hold the valve closed until it opens slightly, then they would pull it downward. But even so I'm not sure it will open fast enough. I have a new idea I'll be testing this next week
Also consider a "barn door" or double door valve for the end. The doors would have less mass and would move faster, plus they are shorter in length and would clear the projectile faster.
Maybe add a spring loaded assist, to speed up the flap & make the flap lighter in weight ?
Entertaining video 👍 ✌️
Glad to see you still active with quality vids :) Thanks for sharing as always and keep up the great work!
When using a burst disc, add a check valve near the end to see if it will allow the gas to escape before the projectile hits the foil.
What if you were to drill and tap a hole just before the first ziptie. then screw in a Schrader value of some type so you could hook up a pump to pull a sort of PRE-vacume before pulling out the plunger.
Great Video as always! I'd love to see more Coaxial Cannons!!
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.
Still underrated channel!
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.
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!
You could try mounting a strong magnetic beneath the hinge, and also mount a second strong magnet to the top of the valve face. When it bursts open, the magnets should connect and prevent the valve from bouncing back.
subbed due to simple and interesting video's without the hype! well done
I enjoyed this video! This video is even more proof that you do indeed read all of your comments!
Oh and you just said you read all of your comments again!
What's your real name?
Where do you live?
What's your background?
I think a Q&A is in your future.
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.
Would you ever consider fashioning spitzer type ammunition for this cannon? The thing seems to be plenty destructive with pvc caps alone, but I wonder how the ballistic properties would be altered.