Very interesting. Wonder if some company makes a fan that rotates in the opposite direction? That way it wouldn't spin around if the fans were configured correctly - two clockwise and two counterclockwise.
Im guessing you would just flip one in each corner, to get the same effect.
Could prove tricky controlling the hover with 4 different fan knobs, but sure
8th grade science teacher giving you homework for tonight: Think about that for a moment and write why it would or why it wouldn't work. Hint: brushless computer fans don't run backwards by reversing polarity.
For a fact, But the goal was to gain stability, yes?
So yes it would have half the power/torque of 4 CW props, but a better layout for a stable hover.
The adding, detracting of power to the fans would have to fill in for there inability to reverse thrust.
You mentioned flipping two of them- with two thrusting downwards and two thrusting up, it will eqalize very well and stay parked on the ground.
Perhaps a 5th fan mounted as a vertical stabilizer like a conventional helicopter would work best.
Use a 5th like a tail rotor...
That's about the only way to prevent autorotation without opposing prop rotation and corresponding props.