I've not come across being able to do negative throttle to reverse the prop direction, it would take a huge amount of motor torque to do it and it just wouldn't really work on a quad. However.... I've also seen one quad build with props that can change angle (like a helicoptor) which can effectively do reverse thrust in a fraction of a second. You can get some insane agility like this, I don't see it becoming commonplace though.
Acro - Acrobatic mode, ie without the self levelling. So if you hold pitch forward it will carry on tipping forward and invert. It's the thing that the Hubsan really misses out on, seems odd that it doesn't have a way of switching it off (or at least not that I've come across anywhere)
Acro - Acrobatic mode, ie without the self levelling. So if you hold pitch forward it will carry on tipping forward and invert. It's the thing that the Hubsan really misses out on, seems odd that it doesn't have a way of switching it off (or at least not that I've come across anywhere)