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- Hacker News
- Projects like this are inspiring. Love it.
I should build something this weekend…
- I mowed the lawn.by duxup
- There were designs to hurl masses from the Moon also with a sling. Massively less infrastructure than a linear mass driver.by Gravityloss
- Like [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=+An... [2] https://arxiv.org/abs/2410.09616
by mncharity - What about the guy that jumped from space and broke the sound barrier?
https://www.guinnessworldrecords.com/records/hall-of-fame/fe...
by amai - Not a trebuchet is itby Mikachu_42
- It 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.
by 27183 - The 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.by itronitron
- I think this ends somewhat at Spinlaunch: https://arstechnica.com/space/2025/04/spinlaunch-yes-the-cen...by superxpro12
- I thought it was neat that the dyneema string he used is the same stuff they use on new (expensive) bike spokesby elchief
- Seems 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.
by MomsAVoxell - Drone defense? :-)by zellyn
- I 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.by jijijijij
- > deal with avalanche conditions
Swiss solution: chuck some explosives out of a helicopter https://www.youtube.com/watch?v=H519qhLnRtM (start at 1:20)
(In the image at 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.
by red_admiral - Or we can just accept it as a cool gimmick, we don't have to kill animals with supersonic trebuchets reallyby toasty228
- I 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!).by gattr
- > 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.
by andrewflnr - I 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.
by nkrisc - How 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.
by hinkley - One possibility is to mount the trebuchet on a tiltable platform and tilt it to a suitable elevation, say 45 degrees.by glitchc
- > How do you responsibly test something like this?
Into the ocean, I would hope
by Razengan - It's shooting 3d printed balls, I imagine they don't stay supersonic for very long. Significantly less dangerous to others than driving a car.
- He explains that the field he is shooting towards is over 5km of empty field. He also started his tests with much lower weight and speed to ensure proper behavior before getting up to full speed.by RevEng
- He has fairly specific mechanically timed release control over it — within 0.5 degrees.
But he also used an extremely lightweight ball projectile — a few grams of 3D printed plastic — because he was only interested in the launch speed. And he pointed it in a direction where there were no people for miles.
by dofm - Very early in the video, he explains that while previous builds used steel ball-bearings, that's not responsible at these energy levels, so he switches to lightweight balls made of biodegradable plastic. There's comparatively little energy in the projectile after release, and it's only supersonic for a few feet.
Further, you test in an enormous empty field, as he's doing.
by myself248 - Also (mentioned by Tom), this elastic-powered supersonic trebuchet is an excellent video: https://www.youtube.com/watch?v=gdXOS-B0Bus
- the "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.
by genewitch - This would qualify more as a Ballista than a trebuchetby srean
- That device is so much more scary! Both really demonstrate the ridiculous amount of energy stored in a pinch of gun powder. And I presume gun powder is quite inefficient at driving the projectile, too.by jijijijij
- His dyneema driven drum is eerily similar to the dyneema driven drum (called "snek") https://rowingbike.com/nl/model/thys-222-revolver#content-7 on the Thys rowingbike https://rowingbike.com/nl/model/thys-222-revolverby tromp