Have you verified the lateral C of G? If itās always rolling right, is the right side of the plane heavier? Are you pushing down with your thumb or grip when you release the plane? If itās rolling right is the right elevon going down?
lateral CG is balanced. same weight both side. no grip when release. checked FBWA the right elevon went down when rolling right. Itās weird same plane setup sucessful two daus ago. But it rolled right and crashed 4 times after that.
Check to see that control surfaces deflect in correct direction in BOTH manual and any of the stabilized modes ( including auto ) . If you have things reversed in both your radio AND your arduplane setup that for me is a red flag .
Check to see what your board orientation is set at. AHRS_ORIENTATION should be set at 0 if your FC is installed in the normal orientation ( top side facing up , arrow facing straight forward ) . Otherwise set this parameter to match your installation .
Finally , Iām not sure if this one would cause your crash but remember to have plane facing the same direction as you intend to take off in when you boot up and initialize IMU .
Thanks for the reply. I confirmed the deflect and had one successful flight before.
The board is 90 yaw and the setting matched.
Itās my first time heard about the final point. I place plane facing north when initialize IMU since thereās no compass. If itās not facing north, the direction is not correct when rotate the plane before takeoff. Could you give more information about why need to face the plane to the takeoff direction other than north during initialization?
Youāll find it in the Wiki . Once again Iām not sure if violating that one is that serious .
I learned about it the hard way one day . I initialized plane on the ground , got gps lock , etc , etc , then something happened at the field where I had to launch in another direction . I was using auto launch like you are . I threw the plane and it climbed about 20 feet , rolled over on itās back and proceeded to do a 180 and head in the direction I initialized the plane in . I killed the throttle and let it crash not knowing what would happen next .
Wellā¦ its definitely as the Wiki says - when we unsupress the throttle
we lock in that heading - and not before.
Do you think the wiki description needs clarification?
If so, do you have any suggestion?
We could explicitly mention itās nothing to do with heading-at-power-on
(which FWIU is used by some ājust-get-me-homeā autopilots). Note that
there are several good reasons for us not to do that - one good one is
that we might not really know our heading if you donāt have a compass (we
then generally require movement to determine our heading).
Painless360 has a detailed video on this . The takeoff bearing is fixed upon GPS lock .
To me that is synonymous with initializing the IMI since they happen together upon startup .
Thanks for the clarification. I noticed this I need to point the plane to the north if not use a compass during startup. If not, the heading degree will not be correct.
Does this suggest set up a takeoff waypoint is better than using takeoff mode? at least the plane knows the takeoff wp is the target direction.
Thanks for the clarification. I noticed this I need to point plane to north if not use compass during start up.
ā¦ what difference do you see based on the planeās initial yaw value?
Does this suggest set up a takeoff waypoint is better than using takeoff mode? at least the plane knows the takeoff wp is the target direction.
Thereās less that can go wrong with a takeoff wp - but its far less
convenient than takeoff mode. We do a chunk of work to try to deal with
bad headings in takeoff mode.
The different is the delta between north and the direction the plane point to when power up.
For example, if the plane is pointed to east during powering up, there is 90 degree delta between the plane pointing and real direction when rotating plane before taking off. I think this is due to the initial degree is zero when powering up without a compass.
Thatās why I point the plane to north when plug in battery. Not sure if I need to do this or not. I think the arduplane will learn the direction from gps track when moving enough distance.
This is not true. I have performed a 3 digit number (more than 100) of successful āAuto Take offāsā on different ArduPlane versions from 3.9.4 up to 4.0.6 without the need of a compass.
Normally the EKF performs a Yaw alignment after achieving sufficient speed (greather than 5m/s AFAIK).
The usual messages of a typical āAuto Take Offā are shown below.
The status message of the EKF yaw alignment is shown bold.
