This is a sling bow model that I made in fusion 360 that was heavily inspired by a video by lisx on YouTube (he made a very similar looking one with PVC pipes). To make this, you need some slingshot string (latex strings) that you can get on Amazon (I got a 10-meter-long string of 4.5mm diameter for 15 Canadian dollars on Amazon) or you can probably find some cheaper stuff on AliExpress, or maybe smaller length on Amazon if you look enough, and a smaller diameter string to fit in the arrow slit (personally I used a shoelace from an old shoe, and it works wonders), and finally, this 3d printed model. To put it together, you can go check out lisx's video on YouTube and try to follow his instructions, although they are very unclear.

The one I made (the one in the pictures) so far has held up just fine, and the way I assembled it, it seems to shoot just as fast as the one in lisx's video, however the arrows I was using did not have any fletching, so the arrows were kinda just going sideways. I was still able to shoot right through a can and make it stay in wood, even with a very dull point (i was using old, messed up arrows basically)

I didn't do a very good job at putting it together, so I'm sure it could look much better than mine, i just didn't bother making it look nice.

I printed it in 0.28mm layer height, printed it horizontally and supports on build plate only, (most printers should be able to handle the overhangs, but if yours doesn't, you could try printing it vertically, although it would make it more fragile since the layers would be in an unfavourable direction) I also printed it with only 15% infill, and it doesn't seem to want to break, but if you want to be sure that it will not break, you can set it to a higher infill percentage.

(Note: the barrel in which you shoot the arrow is a little bit small, so perhaps arrows with actual feather fletching would be a tight fit. If anyone downloads this model and actually uses it, just tell me if I should make it larger, since i don't have any arrows with real feather fletching to test it with, or if it works fine (and no, other more rigid fletching will MOST LIKELY not work with this, regardless of how large the hole is)).

(Other note: I printed mine in lime PLA+ because it's supposed to be stronger than regular PLA, but it might be fine in normal PLA)

Update number 1: I got my hands on feather fletching arrows and tested the original one, and it was deflecting the arrow a lot because it was touching the feathers a lot, so I made the barrel bigger. It seems to shoot way more straight now.