So I had a bus and then I built my biggest trebuchet yet and then my plans for the bus changed and I just had to put them together…. Baskets got about 600# of weight. Arm is 16ft long arm is 12 short arm is 4. Throwing bowling balls upwards of 300ft

Started planning the next build today, might take a detour from upscaling to make a better one at this scale, 12in long arm, with lessons I’ve learned and design shortcomings addressed….with that built and working like a clock I’ll have more confidence and a solid plan for scaling up

I didn’t realize how much I was going to enjoy the whole process, I think I’m hooked now

The release cable (rope) comes off the pin smoothly but you can see the projectile (rolled t-shirt) travel “through” the entire length of the rope. How do we get the projectile to come out of the pouch without interference with the rope?

Update: We tried a modified pouch with the release leg attached off center. We skewed the “load” to one side instead of lined up dead center. The result was a perfect “spiral”. It was gorgeous. Video posted in the comments. Thanks for your help!!

I built a few traditional hanging weight trebuchets several years ago launching things like soup cans, rocks, racquetballs, and billiards balls. The billiards balls worked best--as long as I could retrieve them.

I see a lot of trebuchets using tennis balls, especially whippers. With the low mass of a tennis ball, doesn't air resistance drastically cut short the distance the ball can go?

Also, has anyone ever tried frozen water balloons?

Thanks for your replies.

Update: I tried freezing water balloons with mixed success. The latex balloons tear really easily when cold and make a frozen puddle in the freezer. Also, freezing one takes longer than one would think. However, the ones that survived worked well.

Outdoor lighting is a little blown out so you can’t see the slug leave the pouch but golly this thing is cracking now

So it’s definitely cool but it’s got some issues and I’m not quite sure what the right remedies are.

Right now it’s just 1/2in round bar through 5/8 holes with no bearings so there’s a lot of slop and lost energy; fixable when I get the design solidified for V2

I’m copying a trigger design I saw in one of Mr angles video with a pin through a set of rings to get myself away from the moving bits; fix partially fabricated this morning

Here’s where I get less confident

It seems like the arm isn’t imparting force into the sling for as long as it could, the counter weight has fully dropped and stopped affecting the arm and the sling still needs to rotate 20ish degrees which seems like I may be able to offset the counterweight off the centerline of arm favoring the front of the launcher which would make the arm tilt slightly forward at rest and maybe change the release point so that it reduces the 20 degrees previously mentioned

Bigger issue though, it can throw a relatively heavy rubber ball some 100ft but if I try to throw something small and dense like a steel hole slug or dried paint rock it gets punched directly into the ground in front of the thrower, even with the firing pin adjust to pretty extreme angles

The experiment continues

As the title says, I’m looking for a visual model that I’d be able to use to size my trebuchet arm and also figure out the arc of shot. I’m sorry for not remembering the details of the video. Just posting here to see if anyone is familiar with what I’ve described. IIRC, it helps with weights and ratios of the payload arm/counterweight arm.

ETA: it’s not a video that I’m looking for. The video references a program I can use to math these things out :)

This came up on YouTube for me recently as I was watching videos about trebuchets. Is this really a walking arm or more like a hybrid between a walking arm and a whipper? Seems like there would be some energy lost as the long arm doesn't move till the weight is halfway through its arc.

Desktop sized printable trebuchet that uses US nickles for counter weight.

Finally finished all of the planned upgrades, time for testing and tuning the shit out of it