Upside-down flying of helicopters

I recently learned inverted (upside-down) flying of helicopters.
Check it out:

It is called inverted because the helicopter flies upside-down
but also because the controls will act inverted.
Inverted flying is quite difficult but can be learned within a few weeks.
Flying helicopters inverted will teach you three-dimensional thinking.
It is quite confusing at first but also very rewarding if you succeed.

So how does a helicopter fly upside-down you ask?
Well, simply speaking by pushing the air into the opposite direction.
This is done through a complicated mechanism called swashplate
which essentially translates the (non-rotating) controls to the rotating blades.
This can change the pitch (angle) of the blades into the opposite direction.

The swashplate is a quite remarkable piece of engineering
and my above explanation is overly simplified.
A non-simplified explanation can be found here:
https://en.wikipedia.org/wiki/Swashplate_(aeronautics)  

While inverted flying is possible with all helicopters it is usually only used
with model helicopters. But it is possible with big ones too :)

By the way, the model helicopter I am using is this one here:
https://www.banggood.com/WLtoys-V977-Power-Star-X1-6CH-2_4G-Flybarless-RC-Helicopter-p-914247.html?p=IS170311494644201706

Cheers, and happy flying!