Vacuum Rocket

[@HVM_fi]

Rockets with failing o-rings give me anxiety...

[@dolovo_gaming3081]

Oh god, I just realised it

[@nerfingdodos2707]

Is ur profile pic an octaweb from a falcon 9?

[@HVM_fi]

@@nerfingdodos2707 Yes, it is. "Petolinnun peräpää"

[@Saikiran-pf1ry]

Challenging stuff(pun is intended)

[@JustMe-fl1db]

I bet it had more to do with the 3d printed section than the o-ring leaking, tbh

[@AppliedParanoia]

Was fooling with a 5-ml syringe once, decided it would be fun to block the end with my thumb and pull back on the plunger. When I released the plunger it sprung back and made a jolly sound. That was good fun, so I figured the same thing with a 60-ml syringe would be 12 times the fun. It wasn't - when the plunger hit the front of the syringe it drove the luer-lock taper into my thumb, cutting a perfectly cylindrical hole into my thumb. Bled like a stuck pig and took weeks to heal, and hurt like hell too. 0/10, would not recommend

[@msmeyersmd8]

Scalability can be a “bitch” in many scientific endeavors.

[@nicolashaller5863]

Lucky me I only got 30ml syringes, did the exact same thing, but these don't cut you, only hurt real bad XD.

[@cornyboi4434]

Lmao 12x more fun😂

[@777-p2t]

Wind up with a air embolism becareful

[@Armuotas]

@@nicolashaller5863 Yep, can relate. I think it's a learning step for any kitchen scientist that got hold of syringe: I wonder if I plug the end and pull the piston will it slide bac.... MOTHER FAAAA!!

[@Nighthawkinlight]

Ha! Have you seen my plunger vacuum cannon videos? I never thought of launching the cannon itself.

[@TomStantonEngineering]

Hey Ben!! Yes your videos inspired me to convert the rocket into a cannon haha! I'd like to build a cannon as good as your setup to possibly launch a projectile with 'fold out' fins and a parachute system. Would be cool to see how high it could go! Thanks

[@DirtyRobot]

Ha! Was just going to recommend your videos but you beat me to it.

[@inteloutsidepentium8801]

smooth self promote lmao

[@screaminlordbyron7767]

NightHawkinLight yeah I saw that episode recently it was really cool. I thought of it when Tom mentioned vacuum cannons. Great channels guys!

[@justyeetinlife842]

Channel name

[@Smeggit7]

Now if the syringes had needles and the ceiling had a dart board...

[@Allan_aka_RocKITEman]

*BRILLIANT!!* 😊😊😊😊

[@maxdukhovskoy1406]

That's kinda what syringes are: with needles

[@jqkewastaken1311]

What about a "human test subjecy"

[@ruix]

That thing would be illegal in Europe especially in UK

[@gameyord7182]

Maybe too dangerous??

[@garavonhoiwkenzoiber]

"I can't take my vice outside" yeah I keep my vices indoors, too.

[@namewarvergeben]

Get a room! ...oh, you're already in a room. Carry on.

[@flippinkamikaze8738]

*muffled scream, sound of rustling chains*

[@mattiviljanen8109]

Yeah, it's vice to keep indoors.

[@hyqhyp]

Just some good advice.

[@qislegit.donttrustthemedia6232]

i like turtles 🐢

[@MrGiXxEr]

This needs a handheld pistol type frame!

[@GenBumbleBee]

he's in the UK and there cucked. so someone else need to do that

[@borzoi2607]

@@GenBumbleBee lol fuck off brainlet American

[@jack91405]

And using syringes with needles (for better aerodynamics of course).

[@MrGiXxEr]

@@jack91405 Yes! A "syringer"!

[@Eric2300jeep]

KZbin: "It looks like a gun! *DEMONETIZED!*"

[@integza]

I love how you always sneak the science into your projects man :D

[@donjones4719]

Umm... scientifically speaking, it's not a rocket.

[@maxk4324]

@@donjones4719 could you elaborate on what that has to do with @Integza's comment?

[@donjones4719]

@@maxk4324 The clip is titled 'rocket', and he uses that term for the syringes launched at the beginning. In scientific terms a rocket is something propelled by expelling mass to provide thrust, not just anything launched vertically. So, the most important part of the science is missing. Yes, I know Integza is referring to the diagrams, etc. And Tom S isn't trying to be a science show. Just wanted to point out I can't give him the full credit for science Integza did, hopefully in a mildly humorous way.

[@JohnSmith-mt8fd]

Yeah, so gay, iff you ask me, homoerotic.

[@fezii9043]

@@donjones4719 ehm, what

[@RSmerlinRS]

'I dont really plan to put a hole in the roof of my shed' No one does.. but thats how it happens :P

[@benstewart5334]

I like at 3:42 when it launches you can see the water condense as the pressure increases

[@msmeyersmd8]

Ben Stewart Maybe there’s cavitation in the condensed water that gives a huge energy boost with the 10cc syringe. With the high speed camera in total darkness he could look for blue/UV photon emission. Water cavitation creates an incredible amount of heat that results in photon release. I’m curious if that might be happening and resulting in a huge energy boost. I’m not sure of the mechanism of translating that into kinetic energy. So I doubt it. But I am curious?

[@ritwikreddy5670]

@@msmeyersmd8 cavitation directs the surrounding energy to a much smaller point, making it more effective in destroying the containers the vapour is in, but it doesn't produce energy of any sort. Since the syringe is an enclosed space, any cavitation if significant would only contribute to shattering of the syringe and not to its movement since its an internal force.

[@bkkl1986]

cool catch! I was mostly fixated on the oscillations in its movement after release.

[@connermcgrevy2162]

Some anti-vax kid walking Flying syringe hits him in the arm Mission Accomplished well done

[@krek420]

One of those sleep juice syringes work from far away put the med in that and even if he pulls it out hes got that shit in his immube system

[@MADMAX7330]

Although I'd rather target the Anti Vaxxer kid's mom

[@furblokeEN]

@@MADMAX7330 Nah vax the kid. They shouldn't suffer for their parents ignorance. Sod the parent tho lmao

[@NICEFINENEWROBOT]

@Steve Ausrin Ka-boommmm!

[@biko9824]

This isn’t anti-facts to be honest.

[@animalmother556x45]

........KZbin videos from America- “I’m going to dump 500 rounds through this .50 caliber machine gun into a pile of watermelons” ......KZbin videos from UK - “plastic syringe rocket thing in my backyard”

[@loganjamesonhatch5050]

So dude, after he said 110 mph I though "hmmm, wonder what would happen if you turned it on its side"

[@MATTB-rd1us]

I enjoy both;)

[@Minecrafter-uh6qv]

balanced, as all things should be

[@deadbeatdon]

It definitely depends on the 'Muricans you watch. kzbin.info/www/bejne/ZnWuiIaOqNmLq8U I do wonder what the melons ever did to the nation though.

[@msmeyersmd8]

They were giant GMO seedless watermelons with a terrible bland taste. And no nutritional value. Those melons deserved what they got. 👍🏻😎🇺🇸 ‘Merica

[@Alxium]

What if you put some diesel fuel in the syringe? Would the sudden pressure change when the piston reaches the top cause the fuel to ignite and perhaps cause something interesting?

[@FIoGro]

No because when it's up, there are almost no molecules of air to ignite the fuel

[@EricWaterfall]

@@FIoGroso could you mix it? Like equal parts air to diesel?

[@ytfp]

I would suggest eye protection for anyone who attempts these especially with children. Love that you do the math behind each project.

[@tychus7]

@Angus Rae why

[@tychus7]

@Angus Rae what is your problem asshole. You're like seven go back to playing with cars.

[@justinhoffman5339]

Gives new meaning to the term "shooting up."

[@redsquirrelftw]

I like the slow mo shots and how you can see where energy is "wasted" and where it could be improved. Like the wobbling or the bouncing when it hits. Not sure how you could prevent those but it's still neat to see as in real time it happens so fast you would never see any of that.

[@joppesvarld8741]

FINALLY! I saw the story and I was like WHAT ABOUT THE VIDEO!!! Hey little teaser!!

[@quadcorei8085gen2]

People: designing high pressure water rockets for decades chasing higher and higher altitudes. Literally no one: Tom Stanton: I wonder if it works in reverse?

[@Vastafari34]

2:37 Tom is awesome. I love how he teaches by showing his failures.

[@gcKukie]

That rocket clearly says single use, but you've launched it several times.

[@Hmmidkboutthat]

6:02 “Here we go!” *two seconds later* “oh” The dissapointment ha ha😊 KEEP UP THE GOOD WORK!👍🏻

[@marcoronzani7197]

Make the projectile with 4 retractable wings made like a quarter of a sphere that rotate into the body, and are pushed by springs out right as the tube goes missing and the rocket deploys them to stabilize!

[@Allan_aka_RocKITEman]

Agreed. I was thinking along the lines of retractable fins for stability.

[@IExistSometimes]

I'd love to see more of that vacuum cannon idea; I'm sure you could make some huge efficiency gains with a few tweaks.

[@ms-fk6eb]

Hell yeah! Vacuum cannon series!

[@samuelpierce2.088]

m s Better yet: Multi-Vacuum Rocket Revolver. :3

[@johnnykatze7467]

Time to make a “Doctor cannon”

[@Sharpless2]

so he can vaccinate us even faster

[@johnnykatze7467]

Dead Meme You seen jeorge spraves (slingshot channel ) video on the double barrel mandatory vaccine air gun?

[@Sharpless2]

@@johnnykatze7467 yeah ive seen that lmao i want a doctor like him tbh.

[@redsquirrelftw]

Could be a super hero that is dressed like a doctor and has a cape. VAXMAN!

[@InsanePigeon]

It's docta time

[@johnbaines9580]

Tom - try a smear of vacuum grease to seal the o-ring leak and also overcome the friction.

[@BowlGOfficial]

how about glue

[@sam-rs8wg]

BowlG Official what.

[@JohnnyForehead]

It's most likely the plastic that is leaking. Printed parts are notoriously leaky.

[@jonhohensee3258]

@@JohnnyForehead - YOU'RE leaky.

[@Oldschool_Gamer_]

@@JohnnyForehead could try an stl print, they should be a lot less leaky.

[@Gruuvin1]

"It's all fun and games until somebody loses an eye!"

[@morphman86]

An excellent demonstration of how it's not the vacuum sucking, but the air pushing from the other end. If it was a suction from the vacuum, the syringe would not go flying, as equalized energy would be achieved as soon as the vacuum is gone. You can try this yourself with a rubber band and just about anything light enough, like a piece of lego. Stretch the rubber band, place the lego in the path of the rubber band and release. The lego goes flying. Now stretch it again and place the lego right at the point where the rubber band is no longer contracting. The lego barely moves. This is because all the energy has already been expelled at that point and there is nothing left to transfer over to the lego.

[@Californiamartinez]

Tom you got sponsorship! Congrats man! Big thanks to Skillshare for sponsoring all my favorite content... going to check it out now!

[@louisshelley6631]

For the vacuum cannon you could have the projectile to have fairings which could create a sufficient seal but could separate once past the cannon reducing drag. Theoretically.

[@benhitchcock3057]

Thanks for posting this Tom. I printed out the parts and had some fun with my kids this afternoon. One problem I found was that the syringes I used just stuck in the launcher, and the trigger did nothing. Still had a lot of fun though. Thanks for posting.

[@WheezyCyclist]

@6:50 you forgot about energy loss to heat because there was the air that leaked into the chamber when the piston was released the momentum of the piston would have compressed the air inside dramatically heating it up and causing a large drop in the efficiency of energy transfer

[@DeltaDS]

Why cant i have tom as my physics teacher. This seems like a way more interesting way of learning SUVAT

[@mediumfast]

The atmospheric pressure is actually forcing the two pieces together not forcing the plunger up. If it was forcing the plunger up then the two pieces would remain more or less separated.

[@Dev1nci]

What I would like to see from this channel is some more time spent on each project with an aim of perfecting them. They always seem to be close to amazing but not quite there. I like the content, the guy, the setting, the process. It’s just be nice to see things ramped up but ending impressively rather than ending in saying why it doesn’t work so well.

[@memetech-]

that second test looked like an edit with how little it moved

[@isaacfakelastname6629]

When you make a dedicated vacuum canon video try ammunition with a discarding sabot, it will help stability and speed

[@humblenoob7631]

tank projectile vibes APFSDS

[@Cgtam7]

I used this project and made a rifle-looking gun. i inserted the base, then instead of using normal syringe, i used needled-syringe. then i somehow connected the trigger of the base to the trigger of the rifle, and now i have home-made deadly rifle!

[@teaser6089]

8:35 You can see that there is still air in the system, cause just before the blue projectile penetrates the plastic top it formes a dome!

[@jessevvilsteren]

It still leaks a bit but it might just help pop the tape before the projectile hits it and maintain its speed

[@aandykf]

The projectile doesn't seal very good to avoid friction. The air in front of it leaked threw.

[@canteatpi]

there is air in the system at the start, before you pull down the piston, so that's there the air comes from

[@ProjectPhysX]

v = sqrt(2*L*p*A/m), v = projectile velocity, p = air pressure, A = inner cross-section of the tube, m = projectile mass, L = tube length, assuming no friction or leaking. Increase L until the projectile reaches escape velocity.

[@gryfandjane]

Has SpaceX seen this? Seriously, this was a really enjoyable episode.

[@RWBHere]

@Gyf Ketcherside If the recent SpaceX 'test to the max', where Mk1 spewed it’s liquid Nitrogen all over the pad at Boca Chica, is anything to go by, then they might have been watching this video! 😉

[@jawwad4020]

@6:50 I would like to add to the O ring leaking mechanism- more than decreasing the strength of the vaccum, the air acts to absorb the energy of impact- converting kinetic to heat.

[@Void-cn6rn]

I would think the air would hurt it more by converting kinetic to pressure and then just pushing the plunger back down instead of the tube up. 6:38 is a great example of what I'm talking about, you can see the plunger move back like 20% of the tube length.

[@qg786]

You need to also seal the 3d prints as they have very small holes in them. I dropped one of my prints (at 100% infil) in water and the print soaked up some of the water.

[@Francois_Dupont]

spraying some lacquer on would seal it easily no?

[@qg786]

@@Francois_Dupont It would.

[@goddamn8958]

1:47 large syringe rocket test in 3... 2... 1... PFLOPP *beer opens

[@colinwilliams3459]

This reminds me of Peter Sripols alka setzer rockets

[@jonhohensee3258]

No it doesn't.

[@MakerBrain]

Nice! I love how deep you go into every topic that you make a video on.

[@harikishore2514]

6:51 The 'O Ring' always remind the challenger disaster.

[@jonhohensee3258]

Thanks, Captain Positive.

[@PandionStudios]

I built an electromagnetic version of this, tried to hit the resonant frequency of the collapse so that you push off of it, got a bit of thrust but left the project on it's side due to work commitments, great stuff dude!

[@davidvhoudt]

I have had a project in which i made a 'compressed air bottle rocket'. i see that your blue projectile is indeed somewhat instable. However I had a problem with getting really far. When i shot an unweighted bottle it went fast, but lost alot of speed to air resistance. After a while i made a weighted bottle and that one went alot further. I suggest you look into adding (a bit) of weight to the projectile. Of couse if you make it too heavy it will not get the maximum amount of velocity. I hope this helps.

[@tom_something]

One potential limiting factor in the vacuum cannon rocket is the release speed of the plunger. As soon as there's any gap between the plunger and the body, air starts rushing in, but slowly. So you want that gap to open as quickly as possible, increasing the gas flow rate which increases the pressure, which increases the force on the projectile, and since the distance of the projectile is sort of fixed, increasing that force is the primary way to deliver the maximum amount of work, energy, into the system.

[@chiquilio]

I would put rifling on the vacuum cannon to improve stability

[@duodot]

You dont even need rifling, which would be difficult to produce, just angled fins, i.e. fletching

[@Warriorcat49]

He doesn’t even need that, just to make the fins he already has into a hollow, cylindrical base, like a Minnie ball. Much more compact.

[@Tolakamee]

just needs a sabot

[@jonpardue]

Excellent video mixes engineering thinking and practical tests to make a lot of fun and understanding. Great for kids and adults. Thanks for the STL files and enthusiasm! Cura will slice that for the Ender 2 tonight.

[@portersherman5311]

Kid: Mom I want a syringe Mom: Oh god my kid is on drug *starts crying* Kid: *confused* I just wanna make a rocket and shoot it high into the air Mom: *frantically cries* getting high and shooting up oh lord where'd I go wrong

[@lordelectron6591]

Yes

[@williamthomasmi10]

including time lapses of your prints really encouraged me to watch through the ad

[@AmaroqStarwind]

Hey, I have a question for you. Why are pistons and their cylinders round? Why can't we have an engine with square-ish "cylinders" and pistons?

[@akhilsubhash7644]

I think it is due to structurual integrity because round shape spread the load evenly so that strong parts could be made without using more material

[@SM--]

1) Stresses concentrate on the pointy corners of the pistons, eventually eating away the sharp corners and creating leaks. 2) Sealing a sharp corner is harder than a sweeping radius. 3) Machine tools have really hard time machining sharp inside corners, there's always a tiny radius left behind. 4) Lathes and boring machines make it easy to create precise cylindrical shapes (only radius matters) where as square shapes require precision on two different axis (x and y). 5) There are very few advantages in other shapes (packing factor is the only one that comes to mind) Those are the ones that came to mind, of course there's more to it.

[@AmaroqStarwind]

Why not keep the corners round?

[@NitroTom91]

Honda built a motorcycle engine with oval pistons to save on width. Didn't work out too well as we still are using round pistons though.

[@redsquirrelftw]

All the stuff above, and probably because it's also easier to manufacture. You can just spin in a a lathe and then drill/machine the chambers and a round shape is going to be easier to meet the tight tolerances.

[@RWBHere]

Thanks Tom. Vaseline will act as a sealant and lubricant for that syringe body and plunger. Also, with the large tube, if only the top end separates, after being held in place by a diaphragm or other seal, then the plunger plus small end cap will go a lot higher than it would if you tried to launch the whole apparatus. Maybe a ‘Mark2’ video is called for!

[@moodmusicytc]

"something slightly larger" Proceeds to reach down ;)

[@ThomasGrillo]

Thanks for this great demonstration of inertial momentum, in action. I used to play with these, back when I was a kid. Loads of fun. Even attached propellers, with retractable blades to the ends to make helicopters, out of them. :)

[@lancevanvelzen4832]

I used to have syringes breaking like that all the time

[@cavinrauch]

Seeing the piston come to a dead stop at 6:12 is pretty cool.

[@ManuelBTC21]

The front fell off. Chance of a million!

[@camillereboux9489]

once again a really cool video. I have an idea for the vacuum canon : maybe put the rocket on top of the tube and use it as the seal instead of using packing tape . it might allow less air in the canon making it more effective and you will only have resuable parts.

[@jibbajabba4597]

You're gonna need a license for that syringe when the EASA regs come into force it's too fast lol

[@thecaptainnoodles]

Not if they see it after we leave the EU :/

[@jibbajabba4597]

Noah Ali won't make a difference, EASA is nothing to do with the EU.

[@thecaptainnoodles]

@@jibbajabba4597 Oh, ok makes sense

[@virtualtools_3021]

What is an EASA

[@wernerhiemer406]

@@virtualtools_3021 The european equivalent to the NASA.

[@jeffbeck6501]

I enjoyed the problem solving and modifications made. You could make some cool toys with this concept.

[@jacklipper-sagehorn4935]

When you do the sponsor thing can you put text on your screen that said “skip to ~~:~~ if you have seen this sponsor a trillion times before”

[@RWBHere]

How do you get to ~~:~~ ? Can't find it on the map. And do we have to skip? The sight of a middle aged man doing that is a bit creepy. 😁 Couldn't really help it. Literalism sometimes causes me all kinds of trouble.

[@shadowOrgon]

For the vacuum cannon round to be more stabilized and higher, try mimicking an APFSDS tank round (or sabot round).

[@arcterus01]

The volume was a bit low on this video, otherwise cool project.

[@CreatingCreations]

That's super cool! I have recently had a lot fun experimenting with these syringes for different toys.

[@AntonyScerri]

no goggles Tom, i imagine that vacuum tube could be bad news if it gave way. Like the idea though, more fun projects from you, keep it up. The packing tape breaking simply from the pressure before the projectile reached it was a nice feature too.

[@AxelDayton]

Imagine all the pranks you can pull in class with this.

[@AbdulAleemShekhani]

I love how detailed and physics oriented your content is :]

[@Gribbo9999]

Nice one Tom! In the final version of the small syringe it is interesting to see the gas above the piston forming vapour clouds due to pressure drop as the piston oscillates downward and upwards after it reaches its maximum approach to the top of the syringe body at 10:32 an 10:40. Much like the vapour cloud that forms on lower pressure parts of an aircraft wing on a humid day.

[@Redheadthinking123]

Your content is top-notch mate, I'm' surprised you don't have more subscribers.

[@dexterman6361]

If you look closely, frame by frame at 3:40, you can see the momentary high pressure causing what I think is condensation. This pressure causes the piston to jump back down. This high pressure is basically the idea behind diesel engines!

[@optionalcoast7478]

I'd really like to see you do more with vacuum cannons

[@TheRealSpiderMew]

how powerful of a vacuum cannon would you need to launch something into orbit, and how big could that something be?

[@NoName-qv4zm]

A very nice tutorial on how to lose an eye. I love it! Keep up the good work! :D

[@JR-lg7un]

Words of wisdom from Norm Abrams - Always wear these, your safety glasses.

[@GP-vl8en]

I can see two things to improve the rockets distance 1) adding some weight 2) and adding some form of seal it, doesn’t have to be airtight but enough to make sure the air doesn’t go around it. otherwise this is really cool

[@0xDEADBEEF666]

Must resist the urge to scale this up ridiculously large.

[@jainvibhore1997]

Hi there! a little late to party but I think one of the major drawback of the acrylic tube is that it will never let the piston hit the top. In the small syringe you have that tiny mass of air at the top and the piston is able to push the air into that space and make contact with the syringe head. In case of acrylic tube however there is no such reservoir and the trace air is going to decelerate the piston.

[@jackjohnson4524]

Great idea! I used to love making little lever-controlled pneumatic arms out of these by attaching tubing to the end of the syringes, then attaching levers to the plungers. Let’s see a syringe-powered robot of some strange kind!!

[@Wingman4l7]

The bouncing of the syringe plunger at 3:43 and the resulting "bump" effect on the syringe as it launches upward, is very reminiscent of Project Orion's bomb-explosion-based scale test rocket launch footage.

[@davyaldy76]

For further work with the vacuum cannon, consider making a sabot round. That might help with stability in flight.

[@MCsCreations]

Fantastic job, Tom! 😃 As soon as I buy a 3d printer I'm going to print it! 😃

[@Cobra365]

Thank you for touching on this again. Your explanations and slow motion shots are very helpful in understanding what’s going on. I’m looking to get a 3D printer. I’d like something reliable, simple and just good enough to create the stand and lever made in the video. If they’re still too expensive, finding someone to print for me is a good idea.

[@askhowiknow5527]

That vacuum cannon makes a brilliant sound

[@gavinortengren3273]

Whats great is that Tom could easily turn some of these things into weapons.

[@NathanLTPK]

so this is like hyperloop prototype, really really nice.

[@ryanmorrison8833]

Your syringe may have not been leaking as much as you thought. Drawing a vacuum on water will turn it into water vapor. Basically, your lubricant could have been building up pressure in your tube. Silicone lubricants tend to have a low vapor pressure and would likely get you much better results compared to water.

[@dominikkmieciu]

Try to add a flap at the end of the acrylic tube. Under pressure it will be closed and tight, and when you release the pressure should open.

[@Flyguy779]

i think the biggest issue with air in the cylinder is that the energy that would be trancefeered into the the top of the piston ist diverted into compressing and therefore heating up the air inside the piston, onverting most of your kinetic energy into thermal energy.

[@rizalardiansyah4486]

Yes, and i wonder how it would look in a thermal camera

[@Flyguy779]

@@rizalardiansyah4486 depends on how much the tube isolates from heat...

[@humblenoob7631]

Congrats, you made a vacuum cannon! This has been around for ages

[@cartertomasko8686]

Can you share the dimensions of the tube, and then we can make rocket ideas and share stl files with you to 3d print and test?

[@bobfels5343]

Love it how you also show the fails :D, thats how development works: try and imporve!

[@davidaustin2172]

Love your shed!, Mars here we come!

[@thextrmntr]

I think more than the weight, the air leaking is the biggest factor in why it didnt launch high enough. As the piston reaches the top, it looses most of its energy trying to compress whatever air that leaked in, and you get sort of a air cushion at the top.

[@simplesimson1]

some serious rocket science going on there!

[@gennadyplyushchev1465]

Love you skyentific approach. Please build rotodyne, it is very interesting concept. :)

[@Aedrieus]

I don't know if this was ever revisited but, my thoughts would be to add spring-loaded fins to the blue projectile so it is spun as it exits the tube, kind of like fin-stabilised sabot rounds in long range rifles or tank cannons.

[@jacoblawrence9145]

Your lawn looks amazing!

[@richardhanck972]

With the vaccum cannon, it appears that the packing tape is bursting due to air pressure between the projectile and the tape (see 8:39), so there is some significant leakage either past the tape or the piston. This is lowering the potential energy of the vacuum, but preventing loss of momentum due to impact. In theory, if you could remove the packing tape the instant the projectile arrived at the top of the tube (preventing that momentum loss) with a low-friction good airseal on the projectile for maximum pressure differential across the projectile (increasing the potential energy in the vacuum), you should maximize the potential to kinetic energy conversion. So I have this idea... an upside-down T connection at the bottom of the cannon, with a piston/projectile fitted in the long vertical leg. On one of the horizontal legs, you have a vacuum pump and a ball valve. Upstream of the pump you have another, smaller T connection with ball valve that leads back to above where the piston rests. This allows you to pull a vacuum on both sides of the piston/projectile, and close the valves maintaining the vacuum both above and below separated by the piston/projectile. On the other leg of the T, you have a tank of high-pressure air, separated from the T connection by an electrically actuated burst disc (basically some high strength foil with an electrically insulated resistor wire inside, that when enough current flows through the resistor it melts the foil (just enough so it pops) releasing the pressure on one side to the other). At the top of the long leg of the T, you have another electrically actuated burst disc. The burst discs would be connected to capacitor banks to provide the high current necessary for the flash heating of the disc resistors. The lower disc could be manually actuated, but the top disc would either need to be time-triggered or sensor-triggered (possibly by laser-photocell interruption) or possibly a combination of both. So in operation, you would pull a vacuum above and below the piston/projectile. Seal the connection from the barrel above the projectile from the connection below, with the low-friction airseal of the piston/projectile being the only divide between the barrel and connection. Release high-pressure air into the connection below the projectile with the first burst disc, causing rapid vertical movement of the piston/projectile. As the piston/projectile nears the far end of the tube, the second burst disc is fired, ideally just as the piston/projectile is coming into contact with it, minimizing momentum loss due to contacting the burst disc. A high-density projectile inside a breakaway low-density airseal piston/sabot might give you the best energy transfer and post-launch projectile stability... but you might want to find somewhere safer than your backyard to set this off... you might be looking at firearm projectile speeds from this... and I'm unsure how you'd track the projectile after it left the barrel.