not just he blades - the HUB! It looks like a regular adj pitch hub from a plane -
adjust pitch while motor is running! And probably has reverse?
Some boats have a toggle switch for TRIM TAB - this one probably has a switch for LANDING GEAR.
It looks retractable.
I'd like to see it drive through a shallow wachout or gully. LOL
About all that landing gear would be good for is a nice flat beach.
Still cool. Someone sure did some work to get their ideas off the paper.