Plane fly like a dolphin when airspeed is enabled

ArduPlane
,
1

Greetings

My plane fly well in all modes.
I installed an airspeed sensor. I calibrated the airspeed sensor as the arduipilot web resources suggested including a 12 minute loiter with auto cal.

When I enable the ARSD_USE the plane nose rocks up and down during flight ( fly like a dolphin )
As soon as I turn off the airspeed use, the issue goes away and the plane fly straight.

What could be the problem ?

I set the cruise airspeed according to the stall speed of the plane. Also I set the airspeed min / max accordingly.

I would appreciate some experts insights

Thank you

I am flying a talon pro 1350mm. Weight 1.6 KG

2

If you have set the cruise speed “according” to the stall speed of the aircraft, what is then the minimum speed?

It would probably be better (according to Ardupilot documentation) to set the minimum speed 20% above the stall speed.

And the cruise speed between the minimum and the maximum (obviously looking for certain criteria that may well be efficiency, speed…).

3

Hey thanks for the reply

My cruise speed is 12m/s
My min speed is 11m/s
My max speed is 20 m/s

Sorry for my bad English

4

You may need to do autotune again. If airspeed estimate during tuning was wrong it can cause excessive gains leading to oscillations now when you are using the airspeed sensor.