Hacker News Reader

Joerg Sprave did something similar in 2013, but mechanically pushed the ball along the spiral instead of wiggling the whole thing. I like your idea better, and I bet it would be a fun project!

https://www.youtube.com/watch?v=LH8G7atCFSQ

That sounds very similar to the electromagnetic accelerator by Hyperspace Pirate [1]. The difference is that it uses magnets to accelerate the balls instead of mechanical oscillations. And there is no stream in a strict sense.

[1] https://www.youtube.com/watch?v=uNbL3tRZeMQ

I went down a rabbit hole. I remembered seeing guns like that, but they all seem to have spinning barrels. Look up centrifugal guns.

I was sure I'd seen a space launch method but it took me a while to find. It's called the slingatron and has a tube that wobbles like a hula hoop.