Better late than never, so here is mine explanation what is AirMode implemented in Cleanflights fork Betaflight and hopefully soon available also in Cleanflight. Before we will go to any details, please read this to understand how PID controller works. If you know, you might skip it.
In normal flight mode, No Air Mode, flight controller is not using I term from PID controller when throttle stick is low. Why? To make landing nice and easy. It zeroes it. If it would not do it, drone would want to fight pilot attempts to land. That makes sense, right? I term is also not desired during take off. Why? Gyro error might accumulate in I term even before drone takes off, that would result in spinning motors faster and faster (since machine can not correct anything while still on the ground) and in worst case scenario, drone might flip before going into the air. So, zeroing I term on low throttle is good. Or is it not?
There is a set situations when zeroing I term is not good. When? In flight, when pilot pulls throttle back on purpose. During rolls, inverted flight, falls and all those situations when you do not want motors to give thrust and pull you into ground because you are pretending gravitation is not there. Without I term those acrobatic figures are very hard: without I term drone loses stability and will not hold attitude. It will start to drift, even tumble when CoG is away from center of drag.
So, what Air Mode does? Air Mode prevents I term from being zeroed when throttle is low. That way, drone keeps stability all the time, even when throttle is all way down. Plus, together with this mode, new mixer has been implemented that gives much more motor activity with low throttle.
Result? Well, you really can pretend gravity does nor exists. There are plenty YouTube videos showing what Air Mode can do.
How to enable AirMode?
To use AirMode you will need Betaflight 2.1.6 or newer. It was implemented in earlier version, but had a nasty bug. So, use 2.1.6 or newer.
First of all, MOTOR STOP function has to be disabled. Reson is obvious: what would Air Mode do if flight controller would stop motors at low throttle? This can be done in Configurator Configuration tab.
Air Mode has to be enabled in Configurator in Modes tab via AUX channel. It is recommended to have it on separate switch position than Arming. While you should not have any problem with take off when Air Mode is enabled, landing can be hard to impossible.
My solution is 3 positions switch with assigned following modes:
- Armed with Air Mode