Plane, Cruise mode stalling - why zero throttle?

Hello friends, sorry to bother you.
I have trouble understand why my most beloved flight mode, Cruise, is crashing for me.
As soon as I enter it the throttle goes to 0% and after some 20 secs time the plane stalls.

I can’t understand what in my parameters make this happen - Can you?

In this log there are 3 times I enter Flight mode Cruise - all with same result, I hade to bail out before a stall, the air speed gets too low.

Log

You have terrain following enabled… Is that new?

2 Likes

Wow, thanks a lot Mark.

I would never have guessed!
Turned off terrain following and disabled altogether the terrain function, and now the cruise mode works just like it’s expected to.
I don’t need it on this plane.
It’s not really new I think but rather these settings were copied over from a similar plane I use in Europe.

Can you cast some light over why this is?
Karl

I looked through the log and it appears that TECS is asked to glide.

It looks like you have soaring enabled, the plane is trying to soar.

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Mmm strange.
The cut off altitude is set very high like 250m I think, so it will not try to soar below that. The altitude I engage Cruise is around 100m.

It could be that the root cause of the problem is not having terrain tracking activated but the lack of terrain data.

As you can see, the data of 90 terrain tiles are not loaded yet; it could be due to an error reading the sd, missing/damaged file…

I use terrain tracking and I never had that situation in CRUISE.

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I’ve never tried to use terrain following, so I’m just relating what I can find in the wiki.
Since (I believe) cruise mode was the only one set up to use terrain following, it made sense to try disabling that, but I don’t see anything in the log to indicate that terrain data was unavailable.

Perhaps the problem is with the F405 FC; perhaps it has less ram and flash than the FC in your working vehicle?

Thanks a lot guys for your effort and great inputs.
Lots of resonable reasons why this is happening.
@kd0aij
@Lano
@LupusTheCanine

Unfortunately, I don’t have time to dig deeper but just happy to have the Cruise mode resurrected to normal glory.
However, if anyone feel these findings are a concern to how the software is working, please let me know and I will be happy to carry out some test, as per your requests.

K