Chapter 4: VTOL Tilt, Multirotor, and Return Parameters
You can query the AI in AGC for information about all parameters listed below.
6. VTOL Parameters
6.1 Tilt Parameters
Adjust the following parameters for the actual airframe and operating conditions.
QTILTYAW_ANGLE=10 (thrust-vector angle used in multirotor mode; 10=10 degrees). Sets the maximum tilt-motor angle commanded by rudder input in multirotor mode. Ensure that the installed propellers do not contact the airframe.
QTILTFIX_ANGLE=10 (thrust-vector angle used in fixed-wing mode; 10=10 degrees). When enabled, the tilt servos participate in vector control for both aileron and elevator inputs.
QTILTFIX_GAIN=0.6 (fixed-wing vector-control gain; 0=disabled, 0.6=60%, 1=100%).
QTILTMAX=70 (the tilt servo moves to this angle and waits for the required airspeed; 70 degrees).
QTILTRATE_DN=25 (downward tilt-servo angular rate during the multirotor-to-fixed-wing transition: 25 degrees per second).
QTILTRATE_UP=80 (upward tilt-servo angular rate during the fixed-wing-to-multirotor transition: 80 degrees per second).
Transition Parameters:
QASSISTANGLE=65. Multirotor assistance activates when the aircraft attitude exceeds this angle. This is a stall-protection function that automatically engages multirotor assistance at excessive attitude angles.
QASSISTSPEED=9-10. Multirotor assistance activates below this airspeed. Set it to the minimum airspeed plus 1; 10 is generally suitable for T-1. This is a stall-protection function that automatically engages multirotor assistance when airspeed is too low.
QTRANSITIONMS =2000. Duration of multirotor assistance after transition to fixed-wing mode, where 1k=1 second, or the maximum deceleration wait time when returning to multirotor mode.
QTRANPIT_MAX= 5. Permitted pitch variation during transition, in degrees. A lower value produces a more stable tilt transition but places greater demands on the tilt servos and motors. A value of 5 is suitable for T-1.
QTRANSDECEL= 3. Deceleration rate in M/s. This prevents transition to multirotor mode at excessive airspeed; switching to multirotor position-hold mode at excessive speed can cause structural failure.
6.2 Multirotor Parameters
Adjust the following parameters for the actual airframe and operating conditions.
QACCELZ =200. Vertical acceleration. Default: 250cm/s. Use a lower value for smaller aircraft.
QVELZMAX=250. Maximum vertical climb speed (cm/s).
QANGLEMAX =3500. Maximum attitude angle in multirotor mode. Default: 3000=30 degrees. A higher value may be required for a small aircraft to maintain progress into a headwind.
QLOITBRK_DELAY =1. Braking delay after transition from fixed-wing to tilt mode. A very short delay produces abrupt braking, while a long delay increases the deceleration distance. Unit: seconds.
QMSPIN_MAX=1. Maximum multirotor throttle; 1=100%. A higher value is generally suitable for smaller aircraft with adequate power margin.
QMSPIN_MIN=0.15. Multirotor idle throttle; 0.15=15%.
QVFWDGAIN=0.05. Uses the tilt servos in multirotor QLoiter mode to accelerate or resist strong wind. Default 0=disabled; set 0.05 to enable.
QVFWDALT=2. Disables tilt-assisted forward thrust below this altitude. Do not transition to fixed-wing mode below this altitude.
QWPSPEED_DN=150. Maximum descent rate during a mission. Unit: CM/S.
QWPSPEED_UP =200. Maximum climb rate during a mission. Unit: CM/S.
QMSLEWDNTIME=0. Limits the throttle acceleration rate. Normally 0; increase it if the power response is too aggressive.
QMSLEWUPTIME=0. Limits the throttle deceleration rate. Normally 0; increase it if the power response is too aggressive.
INITIAL_MODE =17. Starts the flight controller in Qstab mode at power-up to prevent the aircraft from powering up in fixed-wing mode and spinning the propellers on the ground.
6.3 VTOL Return Parameters
Adjust the following parameters for the actual airframe and operating conditions.
QWPSPEED_DN =150cm/s. Stage-one landing speed in cm/s.
QLANDSPEED=50cm/s. Stage-two landing speed in cm/s.
QLANDFINAL_ALT=3. Stage-two landing altitude. Unit: M.
QRTLALT =100. Multirotor return altitude in M. Select a value that clears all obstacles at the current location.
QRTLMODE=2. Enables hybrid return (=2).
ALTHOLDRTL=-1. Fixed-wing return altitude in M. At -1, the aircraft returns at its current altitude. If an altitude is specified, it gradually descends or climbs to that altitude during the return.
QRTLMODE notes: 1: When the aircraft enters the RTL_RADUS range around the return point, RTL immediately changes to QRTL. With a value of 1, an aircraft returning at a high altitude switches to multirotor return (QRTL) as soon as it enters this range. Entering QRTL at excessive altitude is dangerous because wind may displace the aircraft during the long multirotor descent, exhausting the battery and causing a crash.
2: The aircraft returns according to ALTHOLDRTL and descends in a spiral with radius QFWLNDAPRRAD. The default is 0; when set to 0, WPLOITERRAD is used. The T-1 value is 50M. After descending to QRTLalt, the aircraft switches to QRTL and lands.
For details, refer to “Automatic VTOL Landing”:https://ardupilot.org/plane/docs/quadplane-auto-mode.html For additional parameter requirements, consult the relevant technical documentation.