Differnt behavior of autolaunch from 6.1.1 to 8.0.1

[druckgott]

Hi, yesterday I was out with my INAV Funjet running 6.1.1 in completely calm wind conditions on my hill. As you can see in the video, I launched the Funjet using Autolaunch and it immediately climbed away without any issues.

Then I updated to 8.0.1, and today the wind was again completely calm. I launched the Funjet just like yesterday, but this time it didn't climb at all — it just flew straight ahead.

Both diffs are available, along with videos and logs (I’ve attached several logs, but the behavior was always the same as shown in the videos. On 6.1.1 it climbs perfectly into the sky, while on 8.0.1 it drops significantly and would even skim the ground without the hill being there).

The settings should be identical between the two versions, as I applied the diff from 6.1.1 onto 8.0.1 and then went through all the settings again, since there were quite a few changes between the versions.

One thing I also noticed with 8.0.1 is that at the beginning of each flight, when I released the sticks, the Funjet would sharply pitch down. The longer I flew, the better it got — but I didn’t have autotrim enabled. Unfortunately, I don't have a video of that.

How can I get it to launch and climb like it did with 6.1.1? I also had the feeling that the launch pitch angle of 25 degrees wasn't being reached or even attempted in 8.0.1. Aside from the firmware version, the model and wind conditions were completely identical.

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Diff 8.0.1:
INAV_8.0.1_cli_FUNJET_20250422_141035.txt

log_8_0_1.zip

https://youtu.be/Nk6ZsX12MVo

---

Diff 6.1.1:
INAV_6.1.1_cli_FUNJET_20250421_194505.txt

log_6_1_1.zip

https://youtu.be/qUMhQ43xwJs

---

br druckgott

[Jetrell]

The pitch FF is pushing in both builds.. But the p-term isn't doing anything in 8.01.
The main difference I can see from the logs, Which isn't evident in the DIFF. Is 6.1.1 has rcCommand[throttle] applying 94% launch throttle. While 8.01 only has it applying 80%. Which might explain why it's having trouble climbing if it doesn't have a lot of tractable thrust at low airspeeds.

[druckgott]

But why is this Different in the diff i have 1800 launch throttle.
In both version this is the Same i did Not changed any thing there,hardware setup ist 100% the same.
:
And what can I do against this:
The pitch FF is pushing in both builds.. But the p-term isn't doing anything in 8.01

[Jetrell]

The only change I can think of that might be causing the throttle issue is the removal of max_throttle in 8.0.
Being that you are running the Standard ESC protocol.. I would try to re calibrate your ESC throttle range again for 8.01.

[druckgott]

ok I did a recalibration and will try it again today

[breadoven]

There is also the fact that during the launch rcCommand[pitch] was -277 in 8.0.1 and -416 in 6.1.1 so demanding more pitch in 6.1.1.

rcCommand[pitch] during launch is a function of max_angle_inclination_pit and nav_fw_launch_climb_angle. For 8.01 this works at -277 for max_angle_inclination_pit = 45 (current default) and nav_fw_launch_climb_angle = 25 (-500 * 25/45). Since nav_fw_launch_climb_angle is the same for 6.1.1 I'm guessing max_angle_inclination_pit was set to a lower default value.

Edit:
On checking max_angle_inclination_pit was set at 30 degrees in 6.1.1 which explains the difference.

[druckgott]

But on 6.1.1 it works better. Does this makes sence? If the values are lower the Angeles should be lower or Not? And in 6.1.1 it goes much better what the pitch angle is.

Or do I have a missunderstanding?

Or what value do I have to changed to get the Same behavior?

[breadoven]

But on 6.1.1 it works better. Does this makes sence? If the values are lower the Angeles should be lower or Not? And in 6.1.1 it goes much better what the pitch angle is.

Or do I have a missunderstanding?

Or what value do I have to changed to get the Same behavior?

It's in Angle mode during the launch so I wouldn't have thought the setting changes would make any difference. It should still try and achieve 25 degs during the climb. However, it doesn't seem to do that looking at the log, just about reaches 25 in 6.1.1 but only 15 for 8.01. Would need more digging to understand why exactly.