The Feiyutech FY-20A and FY-90Q are replaced by the advanced FY-30A. A 3axis gyro/accelerometer developed to allow you to fly your aircraft with increased stability and control. It has 3 modes of operation that allow for varying degrees of stabilization.
1) Precise stabilization and attitude correction (return to level flight from any attitude)
2) Normal gyro type stabilization (maintain current attitude)
3) No stabilisation (no effect)
Mode 1 forces a return to level flight upon the removal of stick input being determined by a combination of gyro and inertial signals.
Mode 2 allows for a smoothed stabilized attitude under the assistance of gyro signals.
Mode 3 allows for normal stick control.
Mode selection is assignable to a 3 position switch on your RC transmitter.
Its important to make sure that you setup fail safe to not default to mode 1 else your aircraft will fly straight and level until you run out of battery/fuel.
The FY-30A can also be programmed to do the job of the FY-90Q through firmware and therefor be used to stabilize any quad copter.