Plane: updated release notes for 3.9.2beta2

ArduPlane/release-notes.txt

@@ -1,3 +1,43 @@
+Release 3.9.2beta2, 15th September 2018
+---------------------------------------
+
+The is the second beta release of the plane 3.9.2 stable release. It
+contains a number of important bug fixes.
+
+ - implement failsafe PWM in IOMCU, for AFS failsafe when FMU dies
+
+ - handle reversed channels correctly in AFS failsafe
+
+ - fixed twin motor plane handling in AFS failsafe
+
+ - fixed a bug in Q_ASSIST_SPEED support for tiltrotors that could
+   lead to zero throttle when assistance triggers.
+
+ - lower default PTCH2SRV_D to 0.04 after reports of oscillation on
+   small flying wings
+
+ - added speed scaler reduction in Q modes when at low airspeed
+
+ - fixed synthetic airspeed estimation to be along +ve X axis
+
+ - fixed relaxing of VTOL attitude controller on transition (thanks to
+   Leonard Hall)
+
+ - default COMPASS_AUTO_ROT to 2 on all boards
+
+ - fixed UART speed rounding bug that caused failure at high board
+   rates
+
+ - fixed a short glitch in position control on quadplane transition
+   (many thanks to Leonard for lots of help with this)
+
+ - fixed RSSI voltage from IOMCU
+
+Thanks to everyone who has contributed, and please report all test
+results with this beta.
+
+Happy flying!
+
 Release 3.9.2beta1, 12th September 2018
 ---------------------------------------