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Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone
- MomsAVoxell 2mo agoSeems like such an advance in this ancient technology. It would be really cool to see it applied in interesting ways. I really wonder just how effective this could be as a defense system .. the mind wanders with every update Tom makes .. I imagine an aiming/targetting system would make this an effective, easily replenished, low-resource weapon system for some applications. Attacking feral animals, perhaps? How could an auto-loader work for this .. I'm sure there's a means. Another thing that I keep thinking about, is whether this would be an effective way to launch seed-bombs, or deal with avalanche conditions on a mountain without requiring fire-arms training. A truly fascinating bit of engineering. I hope to see it evolve into an effective delivery mechanism.
- gattr 2mo agoI also loved the video. But I'd think if one wanted to deploy "simple" mechanical projectile weapons at scale, pneumatic launchers would be easier, more compact and more reliable (way less cool-looking and operating, though!).
- genewitch 2mo agolike a potato cannon? I helped design the "reloadable" part of a golf-ball shooter that used acetylene as the accelerant. I don't think it went supersonic, though. There's videos (embarassing ones) on youtube. He eventually designed one that can shoot full cans of monster energy hundreds of yards. the reason i bring it up is we used to design and build pneumatic ones, that could send C and D batteries thousands of feet if you arced it right. that was with ~125psi, we always wanted to build out to 200+ psi, but instead went into accelerant-based cannons and he got a job doing machine drawing with autocad. the rest is history. edit: https://nextcloud.projectftm.com/index.php/s/cobra5x https://nextcloud.projectftm.com/index.php/s/cobra5x we show off the part i designed, toward the end on the "reload" - he designed and built the entire thing.
- qwery 2mo agoSorry to be a bore [that's a firearms joke], but -- while I encourage everyone and their family to experiment with building such devices, with safety in mind of course, it is a lot of fun -- please don't dispose of your old batteries in the natural environment! Really not trying to call you out here, as a teenager I once had the idea to load up my marble cannon with dead AAs (they're free!) and got a "do you really think that's a good idea?" from an environmentally conscious adult when I went asking for dead batteries.
- genewitch 2mo agoWe moved on to oranges really fast after realizing that batteries coming out of the sky randomly was probably a bad idea, even if there were no apparent people around. Don't get me wrong, oranges are dangerous too, coming out of the sky at terminal velocity, but at least when they hit the ground they disappeared into a fine, 3 meter wide mist.
- jpfromlondon 2mo agooh my god, were it not for your redundant comment I might've gone to the forest to discard my collection of depleted batteries, thank goodness.
- MomsAVoxell 2mo agoI dunno, takes a lot of energy to get a pneumatic system up to the same speeds that this trebuchet can accomplish. I see it really as a super-efficient machine requiring very little effort to load .. But yeah, the fact that it's super cool looking - and sounding - is a key factor in my willingness to play with one too, one day. ;)
- monster_truck 2mo agoBasically anyone can go buy a pellet rifle that will easily and consistently clear 1500fps. They're still pretty cool, and will go through both doors of a car
- gcanyon 2mo agoI think the cycle time on this would be far superior to a pneumatic system: cycling this system effectively means lifting ~100 pounds ~8 feet, which a reasonably fit person (who could reach that high) could do several times a minute for extended periods. He got an efficiency over 40% (if memory serves, I watched this video yesterday) -- I wonder between pumping and discharge how efficient a pneumatic system would be, but I can't imagine that it's higher.
- fc417fc802 2mo agoIf the pump were operated by a bicyclist and the projectile feed automated I imagine the pneumatic system would win out by a very wide margin regardless of any reduction in overall efficiency.
- MomsAVoxell 2mo agoOnce this thing is dialed in, a wind- or stream- rechargeable version is the obvious next step.
- gcanyon 2mo agoI've seen potato guns (obviously much larger bore than this) and inflated bicycle tires to 100psi+ How do you imagine making the cycle time better "by a very wide margin" compared to lifting 100 pounds less than 10 feet?
- fc417fc802 2mo agoIsn't it a simple matter of sustained energy output scaled by the overall efficiency? I'm saying that a human cycling can sustain much much higher energy output for much longer than most other forms of exercise. Running probably comes close and swimming likely exceeds both of those but in the latter two cases I'm not clear how you could productively harness energy from the activity with any sort of efficiency so it doesn't apply here.
- zellyn 2mo agoDrone defense? :-)
- toasty228 2mo agoOr we can just accept it as a cool gimmick, we don't have to kill animals with supersonic trebuchets really
- MomsAVoxell 2mo agoWell, depends if killing the animal means having an actual ecosystem functioning again, afterwards. Some animals are living in the wrong place in the world; culling them requires special skills. I get it - animal murdering is cruelty, mmkay .. but so is a wild boar, ripping up wombats and quokkas and witchetty grub-bearing paperbark trees .. Anyway, I do see far more peaceful applications of this, if it becomes efficient and deployable. Could be a good way to launch things at sea, for example. Or even certain forms of glider.
- monster_truck 2mo ago[flagged]
- nkrisc 2mo agoI don’t think this has much practical application as an entire system. Nor is it supposed to. It was built just to achieve and artificial goal with arbitrary constraints. That doesn’t make it any less cool or interesting, but that doesn’t make it useful. Some of the features he used are pretty cool though, like varying the winding drum diameter to vary the delivered torque over the course of the weight drop.
- MomsAVoxell 2mo agoI could for sure see it being used to launch seeds-bombs, or emergency rations, or make a pressure wave on a snow overhang - if the evolution of this interesting experimentation results in a portable version, it would be immensely useful. As a crop protection device, given some kind of energy-harvesting recharging method, a la wind. A bit of imagination makes it very useful.
- andrewflnr 2mo ago> without requiring fire-arms training. You'd need trebuchet training instead, which is probably not better in the long run. I bet there's still lots of ways to kill/mangle yourself with one of these, especially once you've been around them long enough to get casual and sloppy.
- MomsAVoxell 2mo agoAll such weaponized technology carries the weight of danger, but de-weaponized technologies - which is what this represents to me - could mean some break-throughs, too. There are a lot of peaceful applications for a trebuchet. And yes, it'd need training, but its not the training part of explosives training that I think needs to be rendered obsolete, but rather the explosives manufacture and distribution network, or in other words: peaceful applications for a trebuchet.
- andrewflnr 2mo agoPeaceful use of weapons is cool. But that's exactly what avalanche-triggering guns already are, in full. They and trebuchets are both military artillery at heart. As far as I know they still need explosives at the terminal end, too, even when dropped by helicopter, so that part is also not going away (ignoring explosives needed for mining, etc).
- jijijijij 2mo agoI think the only real advantage of this, compared to gas driven projectiles, is the lack of need for gas sealing and explosion resistance of the projectile. The projectile is accelerated much more gently. You can launch combustible, rather fragile and irregularly shaped projectiles. That said, I don't think there is much need for supersonic exit velocities for most scenarios. Maybe you could use it for impact testing without introducing a gas blast or the need of a gas sealing delivery vehicle. But I don't think you would opt for a gravity powered, purely mechanical device then.
- Auracle 2mo agoCould it be built using medieval (or earlier) technology? One wouldn’t be worth anything on a battlefield but a few hundred of them would be interesting. I don’t know if steel that a blacksmith makes would be uniform or strong enough for that spinning arm though. I suppose the string is even worse, though.
- jijijijij 2mo agoI think, if you scale it up a bit and adjust the weight for increased friction losses, you may be able to do it considering available materials, but the required knowledge would be anachronistic. I mean, they could also have built compound bows and repeating, lever operated crossbows, but weren't smart enough. For the string you could use a chain, or just a thicker rope. A presume a bow string has similar requirements and was available tech. For the frame, spindel/shaft and string, I don't see a problem as they appear to be scalable, not restricted by dimensions/weight much. Wood, natural fibers and steel would do. In theory, medieval people in "The East" had readily access (as in no advanced processing required etc.) to everything needed to make highly elastic rubber (for the original supersonic trebuchet), but it would be an anachronistic material AFAIK. You may conceive a variant using maybe an array of bows for quick release energy storage. Wood is plenty strong (in relation to weight), but the arm may critically depend on modern materials, as both supersonic trebuchets use specifically advanced materials there (structured titanium and carbon fiber composites IIRC). For a heavier arm, you would probably need a prolonged acceleration phase, which would be doable (for Stanton's trebuchet), but I am not sure the forces wouldn't tear lower strength:weight materials apart, or if a more voluminous arm may be able to overcome the drag. I could see the fat compressed part of the arm being aerodynamically shaped wood (like a wooden propeller; although "aerodynamic" anything may be considered anachronistic), and the thin tensioned part made from a thin band of steel/bow string. I think, another potential show stopper may be bearings. Not sure you could have the rotational speeds of the arm without precision (ball) bearings and modern lubricants. 2342 RPM would probably the fastest spinning thing at the time. (I wanna see a washing machine gone trebuchet-y, now.) But really, it would be just a curiosity in medieval times too. What's the point of supersonic speeds in a device you can hardly aim precisely? You could deliver the same or more energy by throwing a heavier projectile at slower speeds, without excessive aerodynamic losses.
- red_admiral 2mo ago> deal with avalanche conditions Swiss solution: chuck some explosives out of a helicopter https://www.youtube.com/watch?v=H519qhLnRtM https://www.youtube.com/watch?v=H519qhLnRtM (start at 1:20) (In the image at https://swisshelicopter.ch/de/aktuelles/721-lawinensprengen-ein-muss-fuer-die-sicherheit https://swisshelicopter.ch/de/aktuelles/721-lawinensprengen-... the explosive pack says "do not eat". I'm not reassured that we need this warning for people allowed to handle that.
- krisoft 2mo ago> I'm not reassured that we need this warning for people allowed to handle that. Not sure what type of explosive that is but the rumour is that C4 when ingested gives a high similar to alcohol. Or at least that is what some troops believe. “Amongst field troops in Vietnam it became common knowledge that ingestion of a small amount of C-4 would produce a ‘high’ similar to that of ethanol, and it is possible that this was the reason for this episode.” From the clinical description of a c4 poisoning case. https://pmc.ncbi.nlm.nih.gov/articles/PMC1279680/ https://pmc.ncbi.nlm.nih.gov/articles/PMC1279680/
- MomsAVoxell 2mo agoIf the trebuchet is breaking the sound barrier, a small fleet of trebuchets set in place on the snowfield and set off in an appropriate wave beam, could provide less explosive-manufacture-distribution-usage solutions to the problem. I could imagine this thing gets even more efficient and resilient, attains some kind of wind or sun-based auto-recharging mechanism, and then deployed on mounted areas to shock-wave snow layers. Yes, its possible, no its not real until someone does it. I could imagine it being done. Note: I also like the idea of not having to use explosives, is the starting base. If you would prefer to blow stuff up, that's not what I'm talking about. The evolution of this technology towards an automated, resilient, field-portable version would be interesting. Imagine having a 6-pack of them.
- dundercoder 2mo agoSome parks in Utah use a howitzer.
- daemonologist 2mo agoAlso (mentioned by Tom), this elastic-powered supersonic trebuchet is an excellent video: https://www.youtube.com/watch?v=gdXOS-B0Bus https://www.youtube.com/watch?v=gdXOS-B0Bus
- genewitch 2mo agothe "shot you've been waiting for" was sort of anticlimactic, but the two plywood arm shots after show what it actually sounds like. I think the grass and tree dulled the sound a lot on the metal arm. I actually have a camera that can shoot that at high speed (1200fps), but i'm sure other people have better cameras these days, mine has very low resolution.
- bookofjoe 2mo agoScientific research systems like the SCARF achieve 156.3 trillion fps but at greatly reduced spatial resolutions.
- red_admiral 2mo agoIs that the "nuclear potato cannon" one?
- cricalix 2mo agoSlow Mo Guys have a Phantom that rocks up around 1.5 million FPS. They've used it to show how glass cracks etc. when you get to that speed though, you need a LOT of light, and a very low resolution.
- hinkley 2mo agoHow do you responsibly test something like this? The payload isn't going to follow a ballistic trajectory, it's going to follow an aerodynamic one. You'd probably have to design something special to load into it to aim the damned thing. Which is a road trip to some place very empty in something like a 180º arc. Maybe 225º.
- thot_experiment 2mo agoIt's shooting 3d printed balls, I imagine they don't stay supersonic for very long. Significantly less dangerous to others than driving a car.
- hinkley 2mo agoYou'll shoot your eye out, kid.
- thot_experiment 2mo agoIt's absurdist to be concerned about this and be okay driving a car from a total harm to society perspective.
- earleybird 2mo agoMerry Christmas
- hinkley 2mo agoHeartily disagree. It's the Frankenstein problem. As an engineer, if you can't even start a process with sobriety, rigor, and safety in mind, that cavalier attitude only amplifies as you go down the road from experimentation to design to unleashing your ideas onto the public. It's a harbinger of what is to come if you're being a suicidal idiot during the prototyping phase. If you don't even have respect for your own safety...
- thot_experiment 2mo ago
- ungreased0675 2mo agoProjects like this are inspiring. Love it. I should build something this weekend…
- duxup 2mo agoI mowed the lawn.
- felooboolooomba 2mo agoThis guy absolutely amazing to watch. He also has a 2nd channel that I only found out a few weeks ago: https://www.youtube.com/@TimStation https://www.youtube.com/@TimStation
- noman-land 2mo agoNot only is it a funny name it also appears in my subscriptions list alphabetically right below the main channel.
- huflungdung 2mo ago[dead]
- emptybits 2mo agoHis trebuchet launched a 4 gram projectile at 776 miles per hour. That's obviously extremely lightweight for trebuchet payload, but for comparison, his projectile is approximately 62 grains so approximately twice as heavy as 30 grain high speed 22LR rounds. And approximately 1.5 times as heavy as 40 grain subsonic rounds.
- deleted 2mo ago[deleted]
- drcongo 2mo agoWhat does grains mean in this context?
- bjackman 2mo agoIt's a unit of mass used in the firearms world
- jihadjihad 2mo agoIt’s a super old unit of measurement for mass [0], idea being that a “grain” is a single seed of wheat etc. 1 gram is a little over 15 grains, and there are 7000 grains per (avoirdupois) pound. 0: https://en.wikipedia.org/wiki/Grain_(unit) https://en.wikipedia.org/wiki/Grain_(unit)
- ahazred8ta 2mo ago325 mg aspirin pills were originally 5 grains. A carat was 4 grains. The unit was used by apothecaries, jewelers, and bullet makers.
- superxpro12 2mo agoanother way for america to avoid the metric system at all costs
- rtkwe 2mo agoNo it's an old unit that's stuck around in the firearm world in basically every country. EU bullet makers specify their bullet weights in grains too.
- sdenton4 2mo agoHere's a direct link to the video, to avoid the blogspam cruft... https://www.youtube.com/watch?v=Co57SfcT-h0 https://www.youtube.com/watch?v=Co57SfcT-h0
- duxup 2mo agoTo the blog's credit the video is right there at the top of the blog.
- sdenton4 2mo agoIt was still completely encrusted in crap, however.
- SkyMarshal 2mo agoStill, why link some blog post about it instead of the actual source.
- cineticdaffodil 2mo ago[dead]
- 27183 2mo agoIt would be interesting to scale this design up. Not necessarily in terms of velocity--supersonic velocity for a large trebuchet munition isn't necessarily desirable. What I mean specifically is scaling up the multi-revolution arm and sling release technology to be capable of launching a ~1 ton projectile. Could it be done reliably with traditional construction techniques (wood, treenails, lashings, minimal metal hardware)? AFAIK these are innovations that were not explored historically. It would be interesting to see if they would have been viable. It seems like you could probably achieve a lot more downrange energy using the same amount of materials this way.
- itronitron 2mo agoThe spiral drivetrain seems like the most innovative, and elegant, technology that could be built with old tech. It requires some very strong rope though, so if you went back in time you'd need to really focus on that.
- 27183 2mo agoHemp ropes are quite strong, they've proven themselves for thousands of years in marine applications. You definitely need more thickness to achieve the same breaking strength as dyneema or steel cable but at slower speeds and higher projectile masses the aerodynamic consequences of a thicker sling rope might not matter so much. As for the "drive rope" for lack of a better term (the one that transfers power from the falling weight to the rotating drum) that one can be basically as thick as you like.
- itronitron 2mo ago>> at slower speeds and higher projectile masses the aerodynamic consequences of a thicker sling rope might not matter so much. You make an excellent point.
- superxpro12 2mo agoI think this ends somewhat at Spinlaunch: https://arstechnica.com/space/2025/04/spinlaunch-yes-the-centrifuge-rocket-company-is-making-a-hard-pivot-to-satellites/ https://arstechnica.com/space/2025/04/spinlaunch-yes-the-cen...
- throw310822 2mo agoWhat's extraordinary about this? You can get any amount of energy from gravity and transferring it to a small object doesn't sound like an especially complex feat. It's one of those influencer videos in which someone devotes a disproportionate amount of effort to accomplish something pointless- Mr. Beast does the exact same without any pretense of showing something useful.
- adlpz 2mo agoYou sound fun... This is HN. The trip is the destination, bla bla.
- throw310822 2mo agoNo, I understand, it's the claim from the very first sentence that "gravity itself seemed to forbid" (reiterated later in the text) that annoyed me. It's just making up a non-existent obstacle to hype up the result.
- magicalhippo 2mo agoIt's a bit clumsily written, but I'm pretty sure that's a reference to what Tom mentions in his video, that since g = 9.81m/s^2 you're not getting close to the speed of sound just from falling from a reasonable height, even ignoring air resistance. Thus a traditional trebuchet design cannot reach that speed.
- throw310822 2mo agoBut since potential energy from gravity is mgh and kinetic energy of a projectile is 1/2 mv^2, calculating height and mass of a weight to power the projectile is absolutely straightforward. The terminal velocity of a falling weight has nothing to do with it (even historical trebuchets used a leveraged system in any case).
- magicalhippo 2mo ago
- alexaholic 2mo agoThis is awesome! I wonder how far can you get with a wood and iron build
- elchief 2mo agoI thought it was neat that the dyneema string he used is the same stuff they use on new (expensive) bike spokes
- Gravityloss 2mo agoThere were designs to hurl masses from the Moon also with a sling. Massively less infrastructure than a linear mass driver.
- mncharity 2mo agoLike [1]. But for an "oh, that's cute", here's [2] Launching mass from the Moon helped by lunar gravity anomalies (2024). The Moon's gravity field has lumps (mascons), so low lunar orbits are unstable (increasingly elliptical until ground impact; timescale months; thus satellites requiring powered stationkeeping even with no atmosphere). Paper observes you can run the path in reverse: elliptical ground launch gets somewhat circularized. So for some locations and trajectories, a passive object (no circularization burn) can stay up for days, instead of the hours of a once around and splat. Making for an easier hypothetical catch. Tnx for the muroid runway! [1] https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=+Analysis+of+a+lunar+sling+launcher&btnG= https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=+An... [2] https://arxiv.org/abs/2410.09616 https://arxiv.org/abs/2410.09616
- Gravityloss 2mo agoThat's absolutely incredible. I would never have thought of that. Thanks!
- tromp 2mo agoHis dyneema driven drum is eerily similar to the dyneema driven drum (called "snek") https://rowingbike.com/nl/model/thys-222-revolver#content-7 https://rowingbike.com/nl/model/thys-222-revolver#content-7 on the Thys rowingbike https://rowingbike.com/nl/model/thys-222-revolver https://rowingbike.com/nl/model/thys-222-revolver
- cyberax 2mo agoA whip's end also breaks the sound barrier. It's not at all hard to do.
- junon 2mo agoWhat a fascinatingly misguided dismissal of someone actually doing something to back up their words.
- felooboolooomba 2mo agoJust like a F-35 Lightning II does. Easy peasy.
- B1FF_PSUVM 2mo agoNot to be that guy, but this recent XKCD is suspiciously relevant: https://xkcd.com/3276/ https://xkcd.com/3276/
- amai 2mo agoWhat about the guy that jumped from space and broke the sound barrier? https://www.guinnessworldrecords.com/records/hall-of-fame/felix-baumgartner-first-person-to-break-sound-barrier-in-freefall https://www.guinnessworldrecords.com/records/hall-of-fame/fe...
- Mikachu_42 2mo agoNot a trebuchet is it
- felooboolooomba 2mo agoNo, a baumgartner.
- nirava 2mo agoI've been enjoying his videos for years atp, does really cool stuff, and has the same fascination with flight as I do.
- egberts1 2mo agoUmmmm. In 2007, near a certain defense contractor, we demonstrated a 319'-wire trebuchet mounted horizontally but slight vertical a-skewed for distance/aiming. Used a gnarly large helical gear but with integral diminishing ratio. Gravity-powered in same way but with a 20-meter-ish tower. (Cheaper than a standard 800'-tall trebuchet.) At release time, achieved 10 G-force (payload goal), it's velocity speed was audibly a speed of sound (arguably higher, math says Mach 2.7). That was our lunchtime project, all started from several stage bets, a napkin diagram, and different loser(s) pay for weekly food deliveries. Even demonstrated to some brass from an unrelated project. Fun-time. Oh, yes, lest I forget, bunker-required for safety (where exactly would you stand?).
- dnemmers 2mo agoWould love to see some photos in action, but 2007..defense contractor...makes me think photos may have been frowned upon.
- egberts1 2mo agoDone on company property. Design Owned by company. We did not object for maximum marketing.
- felooboolooomba 2mo agoGood old days. I'd love to see the design for that one. Any chance?
- egberts1 2mo agoNapkin, someone literally used it at lunch time. Some of us ribbed him: "Destruction of classified material!", "call Security!", "PM's (program manager) behind you". No. Wasnt classified, but company-owned. There are clues above.
- xnx 2mo ago> standard 800'-tall trebuchet. As tall as the Golden Gate Bridge?