Takeoff on ALT-HOLD

Hello to everyone,
I tested on an hexa v the Arducopter 3.1. Everything is working fine!!! Althold, Loiter, Drift!!! Perfect!
Gongrats to Dev team.
The only problem that I have, is when I try to take off on ALTHOLD.
Steps to reproduce the problem on this hexa.
Connect the battery
Switch on ALT-Hold, and arm.
Starting to incresing the throtle slowly, when the stick is bellow the middle, the hexacopter, is getting full throtle by iteself, and is jumping very fast up for few sec.
I can’t find where my problem is.
anybody can help me?

P/S this is the copter of a friend of mine, on mine, similar one, there is on problem at all, on the taking off.
Even in ALTHOLD even in LOITER , No problem at all

http://www.eam-rc.gr/log_althold_takeoff.zip

2 logs

Have you tried to increase the motors_spin_armed parameter to 120 or 150?
Is better when using alt-hold and loiter takeoff.

I have seen a similar behavior. The main reason is that in ALTH mode, the throttle doesn’t control the RPM any more but it tells the copter how fast you want to climb or sink. Means, with the copter on the ground, every throttle position below center is meaningless, because the copter just can’t sink any further than sitting on the ground. As soon as you pull above center, the motors spin up and if you are not really really careful, the copter will rocket upwards, because - again - you are not commanding RPM but climb rate, so you have to be much more sensitive with the stick.
That’s mainly a matter of getting used to it and practising it a few times.

[quote=“marco3dr”]Have you tried to increase the motors_spin_armed parameter to 120 or 150?
Is better when using alt-hold and loiter takeoff.[/quote]

Marco Grazie!!!
You are the Man!! You was right.
Bight improvment on 120. Perfect take off on 150!!!

T H A N K Y O U for everything your are doing for us!!!
:slight_smile:

[quote=“StefanG”]I have seen a similar behavior. The main reason is that in ALTH mode, the throttle doesn’t control the RPM any more but it tells the copter how fast you want to climb or sink. Means, with the copter on the ground, every throttle position below center is meaningless, because the copter just can’t sink any further than sitting on the ground. As soon as you pull above center, the motors spin up and if you are not really really careful, the copter will rocket upwards, because - again - you are not commanding RPM but climb rate, so you have to be much more sensitive with the stick.
That’s mainly a matter of getting used to it and practising it a few times.[/quote]

Thank you Stefan for your informations!