Auto takeoff results in belly landing

Hello,

I tried the TAKEOFF mission item for the first time a couple of days ago and experienced a hard belly landing into the grass instead.

I believe it’s due to TECS_TKOFF_IGAIN=0 in the default parameters causing elevator output to almost freeze, so the plane does not gain pitch fast enough.

I would like to ask if it is intended that this value is zero because it basically disables the pitch error correction during takeoff?

TL:DR

When I check elevator movement in FBWA, the elevator actually does move almost the complete way upward on stick pull and plane pitch movement in self stabilization.

When I switch to Auto, I see that the pitch demand goes to 15deg as expected but the elevator does not move up significantly.

After I changed TECS_TKOFF_IGAIN=0.2 , the elevator does move up all the way until I move the plane upwards towards the 15deg, then elevator goes to neutral.

The plane is a sub 250g ZOHD Drift which is has been tuned twice with Autotune while there was no wind.

TECS values have been set manually according to guide.

No issues with takeoff in FBWA.

Share the .bin of the attempted take off. Without the .bin we can’t offer much significant help.

2 Likes

Instead I pushed PR to get rid of the regression introduced by this commit.

I seriously doubt that I am the only one who fell for this caveat.

I have to amend my previous post.

I had issues with reflex on Elevator, SCALING_SPEED, FLIGHT_OPTIONS and TECS_TKOFF_IGAIN. It flys with Autotune Level 8.