Automatic take-off: the launch was felt, then the motor was released
What ArduPilot says:
- Triggered AUTO. GPS speed = N.N
- Armed AUTO, xaccel = N.N m/s/s, waiting N.N sec
In an automatic take-off (AUTO with a take-off command, or TAKEOFF mode) the motor stays stopped after arming until Plane is sure the launch has begun; this is called throttle suppression. “Armed AUTO” means the first condition is met: a forward acceleration of at least TKOFF_THR_MINACC (a throw, a catapult, a bungee), or none needed if that is 0. Plane then waits TKOFF_THR_DELAY (in tenths of a second) so that the hand is clear of the propeller. “Triggered AUTO” means the motor is released: the delay has passed and the GPS ground speed is above TKOFF_THR_MINSPD.
With TKOFF_THR_MINACC and TKOFF_THR_MINSPD both 0 the motor starts TKOFF_THR_DELAY after arming with no throw at all: right for a take-off from wheels, dangerous for a hand launch. Nothing happens, and nothing is said, while there is no GPS 3D fix or the safety switch is on.
Parameters to look at
| Parameter | What it is |
|---|---|
TKOFF_THR_MINACC | Takeoff throttle min acceleration |
TKOFF_THR_DELAY | Takeoff throttle delay |
TKOFF_THR_MINSPD | Takeoff throttle min speed |
TKOFF_ACCEL_CNT | Takeoff throttle acceleration count |
The code that sends it
Triggered AUTO. GPS speed = N.N
ArduPlane/takeoff.cpp Plane::auto_takeoff_check() · Open in ArduPilot Plane-4.7.1
Armed AUTO, xaccel = N.N m/s/s, waiting N.N sec
ArduPlane/takeoff.cpp Plane::auto_takeoff_check() · Open in ArduPilot Plane-4.7.1