[lstodd]

Mostly physics. It's hard to do small jets, mostly because small things get too heat-stressed

I sorta watched a guy trying to build a hoverboard out of 50-kgf jets, it was crazy, hilarious and didn't go anywhere because flying a backpack of kerosene on four totatally unreliable jets ain't much fun in the end. They also cost about $5K each at the time.

[dylan604]

Just yesterday, someone posted a link to a Veritasium video[0] explaining how a jet engine internal temps of 1500°C work when the components have a melting point of 1250°C. I couldn't imagine doing that at a small scale by hobbyists.

[0]https://www.youtube.com/watch?v=QtxVdC7pBQM

[lstodd]

Yes, and those small engines might work for a bit, but then they just burn out, this is inevitable.

If you build an A380 like here you sure don't want to use them unless you want to film it burning down spectacularly.

[dylan604]

Sounds perfect for Hollywood practical effects vs boring CG

[lstodd]

One can wish.

Besides, thrust control is shit even on their big brothers, on those, it was like throttle down - flameout, throttle up on the other two - flameout, oh crap, thank god we're doing tethered tests.

Gas dynamics on these scales are tricky too. Electric is the way to go for this.