add info on Approach for Hybrid RTL

plane/source/docs/quadplane_rtl.rst

@@ -98,9 +98,12 @@ The phases of the approach are:
 
 - in a fixed wing mode when further than 2 times the greater of either :ref:`RTL_RADIUS<RTL_RADIUS>` or :ref:`WP_LOITER_RADS<WP_LOITER_RAD>` (MAXRAD) **plus** a calculated distance needed to descend from :ref:`RTL_ALTITUDE<RTL_ALTITUDE>` to :ref:`Q_RTL_ALT<Q_RTL_ALT>`, the plane will attempt to climb or descend to :ref:`RTL_ALTITUDE<RTL_ALTITUDE>`. If within that range, it will attempt to climb/descend to a linear descent slope, meet it, and continue to descend, as shown above.
 - if started further than 2X "MAXRAD" but closer than above, at 2x MAXRAD it will continue in fixed wing mode at :ref:`Q_RTL_ALT<Q_RTL_ALT>`.
-- when it reaches a point that is within the VTOL stopping distance of the landing point (at the VTOL deceleration parameter limits and current speed), it will transition to VTOL mode and send a message that it is in "VTOL Position1" and continue moving to the land point. If the vehicle is NOT a tailsitter, an "AIRBRAKING" phase may occur before the VTOL transition, spinning up the VTOL motors to create additional braking.
-- once the QuadPlane is within 5m of the land point and moving less than 2 m/s, it will send a GCS message declaring that it is in "VTOL Position2, and final position itself over the land point and begin its landing descent, which will also be indicated by GCS messages
-- if the approach is entered less than 1.5X MAXRAD, it will immediately move to VTOL Position1 state, whether entered from fixed wing or vtol modes, and move toward the landing site attempting to obtain :ref:`Q_RTL_ALT<Q_RTL_ALT>` as it does so.
+- when it reaches a point that is within the VTOL stopping distance of the landing point (calculated using the VTOL deceleration parameter :ref:`Q_TRANS_DECEL<Q_TRANS_DECEL>` which gives the deceleration that will occur as the vehicle transitions to VTOL and the vehicle's current speed), it will transition to VTOL mode and send a message that it is in "VTOL Position1" and continue moving to the land point. If the vehicle is NOT a tailsitter, an "AIRBRAKING" phase may occur before the VTOL transition, spinning up the VTOL motors to create additional braking.
+
+.. note:: if the vehicle is overshooting "VTOL Position1", try decreasing  :ref:`Q_TRANS_DECEL<Q_TRANS_DECEL>` in steps. However, this increases the point before "VTOL Position1" that the vehicle will transition to VTOL.
+
+- once the QuadPlane is within 5m of the land point and moving less than 2 m/s, it will send a GCS message declaring that it is in "VTOL Position 2", and final position itself over the land point and begin its landing descent, which will also be indicated by GCS messages
+- if the approach is entered less than 1.5X MAXRAD, it will immediately move to "VTOL Position 1" state, whether entered from fixed wing or VTOL modes, and move toward the landing site attempting to obtain :ref:`Q_RTL_ALT<Q_RTL_ALT>` as it does so.
 - if in VTOL mode at greater than 1.5X MAXRAD, the  vehicle will climb to :ref:`Q_RTL_ALT<Q_RTL_ALT>`, if below, then transition to fixed wing and start a normal fixed wing RTL, and attempt to navigate to home, executing the approach. The climb and turn toward the landing point will occur at even low altitudes as determined by :ref:`Q_RTL_ALT<Q_RTL_ALT>`, so the :ref:`FLIGHT_OPTIONS<FLIGHT_OPTIONS>` bit 4 for "Climb before turn in RTL" and/or :ref:`Q_OPTIONS<Q_OPTIONS>` bit 0 for "Level Transitions" might be worth considering for the fixed wing initial phases.
 
 .. note:: In cases where it is feared that using the approach feature may result in it being initiated too close to HOME due to the 1.5X MAXRAD distance being too close in VTOL modes, instead of using :ref:`Q_OPTIONS<Q_OPTIONS>` bit 16 to disable the feature entirely, the :ref:`Q_APPROACH_DIST<Q_APPROACH_DIST>` to increase the distance from HOME that the vehicle needs to be to transition to fixed wing and execute an approach,