Alt hold full negative

When I flip into altitude hold the Heli descends at full negative, and then corrects with full positive and oscillates up and down ver violently, thought altitude hold On was wrong so I lowered it, but hen it just went straight down and never came back up.

Is this a vibes issue? An initialize tion issue? Or do I just need to drop the throttle gains?

Any help would be appreciated.



If anybody is going to help you they will more than likely need a parameter file and log.


David R. Boulanger

Of course, I will post that soon

Logs are here … sp=sharing

Please help!
I’ve tried changing all of the parameters I can think of and still nothing
And I’m unsure if its a vibes issue (though they are a little high) because it still goes full negative on the ground.

The logs appear to say that it wants to go up (desired alt is higher than actual) but it still goes all the way down at full speed.

Do I have the collective set up wrong? Everything else works. Is it an initialization error?

I changed Land Coll and that fixed it on the bench, but I don’t think that will help in flight

Check to see if you have thro_mid set correctly at your helis hover point, then you may have to play with your thro. accel settings a bit.
Yes your vibes are high on x and y, z doesn’t look to bad.
It almost looks like you pass thru acro while switching to alti. hold, if so try setting the flight modes so that you go from stab. directly to alti. hold.
Also you can bench test for alti. hold and this is how I did it…
If you are powering the controller from your flight batt. then disconnect the motor wires if you are using a separate 2s pak for your servo’s your fine as long as the motor can not start and the controller and servo’s get power.
So power up the controller, then push the arming button and arm the controller (in stab. mode) then initialize the controller and bring your collective and thro. to mid stick (hover point).
Now switch to alti. hold and watch what the swash does, it should stay put or even slowly rise or fall that’s ok.
If it makes a dive for the dirt or rockets for the sun then check and adjust your thro._mid and thro. _accel also thro._DZ settings a bit.
99% of the time the swash will stay put or slowly rise or fall
Try this test a few times and watch what the swash does, this method worked perfectly for me!
Once your happy with the results try it outside with plenty of altitude…
Best of luck