91–100 of 109 posts
What'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.
How dare someone build something entertaining and tell about it.
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like 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 fe…
Sorry 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 t…
A whip's end also breaks the sound barrier. It's not at all hard to do.
What about the guy that jumped from space and broke the sound barrier? https://www.guinnessworldrecords.com/records/hall-of-fame/fe...
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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.
You'll shoot your eye out, kid.
And he uses light weight biodegradable plastic instead of steel balls.
Most of his projectiles land in the ground not too far away.
Responsible engineering.
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?).
His 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.
What does grains mean in this context?
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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…
Could 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.
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.
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…