Stabilize from 'free fall'

Hello there ,

I bulit me a Hexacopter with a total weight of round about 1250g and habe an APM 2.6
on it with the newest 3.1 Arducopter firmware.
This thing is flying pretty well , everything works fine .
Now my question , wenn I fly up in the sky and stop my motors …let the copter make a 'free fall’
Will ist stabilze again, if I raise the throttle slowly , even when it is upside down or rotating in some direction ???
Does anyone have experience on that ??
Thanx in advance ,

Acdc :smiley:

It depends how much sky is left and the rotation rate. You also need to have enough battery left to stop it.

I have played with shutting the throttle and starting up again, but only at low level. So perhaps my quad has not had time to get seriously out of shape on the way down.

YES - if no props gain good speed in reverse direction (stable fall)
NO, motors star spinning in reverse direction, the ESC will be unable to stop/turn them, and fail to start up until you hit the ground.
This is why I always were for an minimum throttle that keeps motors running while armed, and it will be an option in next firmware release.

The answer is, don’t raise your throttle slowly, you are just wasting time. Give it full power, so the APM can use as much energy as it needs to turn the props in the right direction. When it self rights, and starts to gain altitude, just cut the throttle back to your 50% hover

Hey Thanks for your answers !

When I read your words —it sounds like you tried to stop motors and restarted them - but crashed in the ground ? Am I getting that right ?!?

@Andre-K : You mean, when I drop out of the sky the props start spinning in the reverse direction ,
thats right :wink: and my ESC (Ultra ESC from Flyduiono) are not able to start them again cause the whole think is disarmed ? did I get that right ?
You seem to have experience on the APM 2.6 - do you know the folowing? : If one motor fails on Hex with an APM2.6 mounted - am I able to land ? or will I drop to the ground ?

@Billbonney: So you are sure…no matter what direction my Copter points to during the drop - I could catch it if my motors stay armed and I have enough time to get it under control again ? - that sounds pretty cool -
I like the APM - flew the NAZA b4 - man the APM makes much more fun and the stabilize is awsome.
Fast drops with slow spinning Props is very stable …I like that feature :slight_smile:))

Nice discussing here-
Regards ,

Hi ACDC, no crashes all good just I was not super high when I switched off the motors. So I think it might not go so well from higher. I guess I have to ask, why would you want to do this??

Switching to stabilize will right craft if it’s inverted. The only gotchas are if you don’t have enough height, or if the throttle is set to zero as this will cut the motors. If you keep your throttle around the 50% mark when in other modes, you will be ok.

yes, what Bill said, full throttle, let it sort itself out, then lower your throttle. ensure you have the feature “motors spin when armed” enabled. as if the motors fully stop, there is a risk that the motors may turn backwards and not start correctly (I have been told, never seen the effect).

the real question here is “WHY”?

I have done multiple drops like this, the highest was from 200 meters AGL, recovering at around 20 meters.

I did it cause I wanted to cause the autopilot much grief while testing.

be aware, this is pushing the boundaries, if you value your copter, [size=200][color=#FF0000]don’t do it[/color][/size]…

have fun

I’ve done this too, but it’s not a good idea. As stated, if the motors stop and/or fail to restart, you’ll crash.

I also am not a fan of the idea of giving it full throttle. When I’ve done it, I only give 1/4 throttle until it’s upright. Twice when fooling around with this, I gave it full throttle and it ended up crashing into something as it zipped off sideways due to having full power while sideways.

Acro mode works very well now, so you should play with that if you want to have fun.