Copter Descends While In AltHold Mode

ArduCopter
1

Hello guys,

Today I had an opportunity to try an endurance flight with my other Tarot Sport quad - the first one I built and repaired after crashing on a hillside some months ago.

Upgrade Completed
Upgrade Completed1920×1440 639 KB

This is a Tarot Sport equipped with T-Motor MN5008 KV:400 motors, controlled with T-Motor A ESCs mounted on a third deck. The aircraft weighs 8.0 lbs. I fully charged the 10000mAH lipo for the test flight. I wanted to accmplish two goals:

  1. See that I can get the aircraft to hover in ALT-HOLD mode
  2. Time the flight until the voltage failsafe kicks in to get an idea of its endurance.

I’m at 5000 ft. elevation and the temp. was about 44 degrees F.

Anyway, takeoff was fine and I was able to handle it okay in Stabilize mode, but when I switched to Alt-Hold, it immediately began descending. I then switched to RTL and it dutifully climbed to its assigned altitude and landed. I tried a second flight but again I could not get it to hover in Alt-Hold, so I flew it around manually in Stabilize until the voltage failsafe kicked in and it landed.

Can anyone offer suggestions on what I should look at? I can provide a parameters file as well as data flash logs.

2

Do You center Your throttle stick when switching into althold?

3

Had hover throttle been learned? Post a link to a .bin log and let’s see. Parameters can be extracted from that.

4

I simply had the throttle where I had the aircraft hovering. Don’t think it was centered as it is over powered.

5

This Dropbox link goes to “My Folder” which in turn has a folder called “Data Flash Logs” - inside is a single folder “Flight 01-30-2026” which contains the parameters written out to a file as well as two data flash logs corresponding to the two flights. I hope that you can access them and can provide some guidance.

6

Hover in stabilize is different than in althold. In althold, you need to center the throttle sticks for keeping altitude. Read: Altitude Hold Mode — Copter documentation

By the way, all I see are 2025 logs in the Dropbox. Can you maybe share the individual file’s link here?

7

In general, if You do not need stabilize mode, You can just set centering throttle stick in Your radio and take off in althold mode by just briefly pushing stick up.

Keeping throttle below center in althold will cause descending, and above conter will ascend.

8

Thanks for the response. I will try taking off in AltHold and see if this works for me.

9

After that post a link to that log. As mentioned the others are too old to bother looking at. Perhaps clear the logs on the flight controller before making that flight.

10

I’m good. I tried taking of in AltHold mode and when I good the throttlel stick up to around mid range it took off and I was able to fly it around even though it was breezy.