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Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

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Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#71

Post by 27183 »

itronitron wrote: post #60
27183 wrote: post #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 har…

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.

Hemp 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.

Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#72

Post by gcanyon »

fc417fc802 wrote: post #57
gcanyon wrote: post #35

Earlier quoted context omitted.

I 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,…

If 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.

I'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?

Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#73

Post by mncharity »

Gravityloss wrote: post #62

There were designs to hurl masses from the Moon also with a sling. Massively less infrastructure than a linear mass driver.

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

Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#74

Post by jijijijij »

bethekidyouwant wrote: post #53
jijijijij wrote: post #38

Earlier quoted context omitted.

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.

I’m not sure dropping 50 kg 4 feet… is my idea of demonstrating the ridiculous amount of energy stored in something…

Well, let that drop on your feet. Or have those fat rubber bands slap you in the face... The small pinch of powder in a cartridge got the same punch.

It's not a nuclear bomb obviously, but I feel you would be just as dismissive, anyway.

Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#79

Post by 8note »

cricalix wrote: post #55
genewitch wrote: post #13

Earlier quoted context omitted.

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.

Slow 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.

i dont imagine the low resolution is per se essential the same way the light is. you could maybe figure out ways of syncing the data collection to match each other at that high of speed

Re: Tom Stanton's supersonic trebuchet breaks sound barrier with gravity alone

#80

Post by dundercoder »

red_admiral wrote: post #37
MomsAVoxell wrote: post #2

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…

> 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.

Some parks in Utah use a howitzer.
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