This one is my favorite, a 'cyclocopter':
I don't care as much about the combat as about the efficiency.
That's a big wing airfoil, and it's cheap foam, and it's not as mechanically complex as a helicopter. There is potential here for low-speed heavy lift. I wish they'd included a scale-up of batteries from "Tiny" to "Too heavy to loft", with sustained in place hover times and watts per kilogram as the performance metric.
How about a cardboard plane
That guy is 3 parts genius and two parts absolute madman.
It’s a really interesting project, worth checking out the video where he merged it with a companion computer to do computer vision tasks and inject controls straight into the flight controller https://m.youtube.com/watch?v=uaY2G5Kbj_g
He also has a fun YouTube channel: https://m.youtube.com/playlist?list=PLTSCOv-lGtMax-oA4Pnq8OT...
One of the first flight controllers he coded was in Arduino..
https://github.com/nickrehm/dRehmFlight/tree/master/Versions...
He deliberately kept the code in single file and made sure it was still easy to follow.
It's a little work of art and shows in the most powerful way what such a little microcontroller can do with the right code.
Ironically, he says at some point in one of his videos 'I'm not a software guy' and next gives a masterclass about how it is done.
That was freaking cool.
Oh yeah, this'll scratch an itch.