Thinking this approach out, could someone correct me if I have this wrong.
So he gradually increases the energy transfer from the weight to the arm over the course of the drop. But that arm swinging around must have a lot of energy loss due to friction and air resistance.
This loss will rise exponentially with the speed increase right? So in a sense he is holding his energy budget in a very inefficient phase, with high losses.
Two things support this. A) he spent a lot of time trying to make the arm more arodynamic. B) The spool widening at the end, which is essentially changing back down gears, applying more torque, right at the end when you want speed.
An alternative would be to drop the weight, and let it fall unrestricted until it gets to it's highest speed (this would minimise friction and air resistance) and only at the end of its fall, transfer the energy into the arm.
In this case the arm would only need to rotate 180 degrees or whatever, and not waste energy rotating right?
And then, to take this a step further to make this work there would need to be some flexibility or elasticity in the system to take energy from the high speed falling weight to the arm.
And what you have ended up with is something that looks like.... A whip!
arlattimore 5 hours ago [-]
Tom Stanton has a raft of cool videos, I like the engineering iterations he often goes through to find a working prototype.
kreelman 4 hours ago [-]
Agree!
He has some great videos. I watched this one and was impressed at the calculations, the transparency and the celebration at the end when he reached supersonic speeds.
At least this is a direct link to the video and not blog spam
pino83 33 minutes ago [-]
Or, in other words: There was some text to read and some pictures to look at. For topics in the range of "supersonic trebuchets", I'm absolutely okay with quickly reading some lines of text; dynamically deciding how quickly/thoroughly I read, what paragraphs to skip, etc. What I'll definitely NOT do: Watch a video clip about it.
foo42 2 hours ago [-]
Great video.
Other trebuchet fans who dream of building one some day may be interested in googling "walking trebuchet" for a surprisingly high complexity/results ratio.
londons_explore 3 hours ago [-]
Interesting that his spool goes bigger at the end...?
I would think you want it decreasing to near zero to extract all the kinetic energy from the mass, leaving the mass stationary as it hits the ground.
vanderZwan 3 hours ago [-]
I think the idea is that at the end the sling starts to unwind too, increasing the effective arm-length (that non-linearity is one of the reasons trebuchets are so efficient to begin with). As a result it's possible that decreasing the spool to near zero is like putting the gears of your car too high. Reducing the spool size ensures there's enough torque left to put more power into the final swing.
MomsAVoxell 2 hours ago [-]
I would love for this to be optimized to the point that its portable and can be carried around, assembled on the side of the mountain, and used as a low-cost, efficient way to throw things from one mountain to another, maybe for avalanche control, or cloud seeding, or indeed for seed bombs intended for re-wilding hard to access places, or something.
It just seems like such an obvious tool, rather than a weapon.
alehlopeh 32 minutes ago [-]
You’ve got the solution. Now you just need the problem.
xdertz 47 minutes ago [-]
if you want low cost and portable, chemistry (i.e. gunpowder) always wins over gravity powered.
roer 2 hours ago [-]
You'd probably be better off using a rail gun if you want a carriable launcher
sawjet 2 hours ago [-]
So, a firearm?
__alexs 58 minutes ago [-]
Why move gun, when gun can move bullet?
londons_explore 4 hours ago [-]
I suspect that with a little iterative modelling of the whole system with derivatives, efficiency could be bought from ~40% to ~80%, giving you an extra few hundred mph...
repeekad 3 hours ago [-]
I wonder if Claude has guardrails against hyper optimizing a trebuchet projectile into a proper bullet
voidUpdate 3 hours ago [-]
I'm pretty sure the only reason the video trebuchet wasn't a proper bullet is because it's made out of plastic instead of a ball bearing. Aren't most handguns subsonic?
ezst 3 hours ago [-]
How would you even get Claude involved in that? This isn't your git repo that a language model can scrape for textual content.
MomsAVoxell 2 hours ago [-]
Convert the model to OpenSCAD, put it in a repo, and off you go. OpenSCAD is very LLM-friendly.
ezst 2 hours ago [-]
A LLM may produce OpenSCAD compliant syntax, I don't doubt that, but how do you make it produce designs that fit engineering constraints? How do you even express those to a LLM? How do you validate those? How do you iterate upon them?
The domain of ML-driven design optimization isn't exactly new, is quite specific, and I would need convincing that Claude has anything to contribute to it.
bonoboTP 2 hours ago [-]
It could make simulations and read the CNC templates and the files for the 3D printed parts.
ezst 2 hours ago [-]
And then do what? Do you have any evidence that Claud would do anything relevant with those?
bonoboTP 57 minutes ago [-]
It could come up with design adjustments and measure their impact in the simulation. But the sim2real gap may be too large.
drtoboggan 3 hours ago [-]
Really wondering up to what point I can build a trebuchet in my backyard before the authorities start to complain
xdertz 42 minutes ago [-]
There are three issues that arise
- structural: There are height and size limits on things you can build without a permit
- trespassing: flinging objects onto others people property is illegal
- endangerment: any activity that can endanger other people is illegal
All of these three depend on how rural you live I guess. So in a suburban neighborhood I would assume they get involved very quickly.
rwmj 42 minutes ago [-]
Surely that depends on the side of your back yard?
So he gradually increases the energy transfer from the weight to the arm over the course of the drop. But that arm swinging around must have a lot of energy loss due to friction and air resistance.
This loss will rise exponentially with the speed increase right? So in a sense he is holding his energy budget in a very inefficient phase, with high losses.
Two things support this. A) he spent a lot of time trying to make the arm more arodynamic. B) The spool widening at the end, which is essentially changing back down gears, applying more torque, right at the end when you want speed.
An alternative would be to drop the weight, and let it fall unrestricted until it gets to it's highest speed (this would minimise friction and air resistance) and only at the end of its fall, transfer the energy into the arm.
In this case the arm would only need to rotate 180 degrees or whatever, and not waste energy rotating right?
And then, to take this a step further to make this work there would need to be some flexibility or elasticity in the system to take energy from the high speed falling weight to the arm.
And what you have ended up with is something that looks like.... A whip!
He has some great videos. I watched this one and was impressed at the calculations, the transparency and the celebration at the end when he reached supersonic speeds.
Other trebuchet fans who dream of building one some day may be interested in googling "walking trebuchet" for a surprisingly high complexity/results ratio.
I would think you want it decreasing to near zero to extract all the kinetic energy from the mass, leaving the mass stationary as it hits the ground.
It just seems like such an obvious tool, rather than a weapon.
The domain of ML-driven design optimization isn't exactly new, is quite specific, and I would need convincing that Claude has anything to contribute to it.
- structural: There are height and size limits on things you can build without a permit
- trespassing: flinging objects onto others people property is illegal
- endangerment: any activity that can endanger other people is illegal
All of these three depend on how rural you live I guess. So in a suburban neighborhood I would assume they get involved very quickly.
https://youtube.com/@SteveMould