I don't think you understand my point.
I linked a very simple electric motor to show that unlike almost any other modern technology the heart of how an electric motor can be explored in a hands on, see for yourself way, combustion engines by comparison are wildly complex and stupendously fiddly.
The example you linked of a transmission is still several steps of complexity above demonstrating the wonderful and mysteriously simple mechanism of an electric motor, especially since the leap to understanding a functioning quadcopter electric motor isn' that far from the device I linked.
The leap to actually understand a working practical combustion engine by comparison is a vertical wall.
These links describe practical working brushless electric motors superbly, there is no serious technical barrier to understand here because what makes them compelling is their almost poetic simplicity.