Loss of altitude/control

[motobtn]

Hello-
I have probably around 100 flights in with my phantom 1.
Recently it has been acting really strange.
First it was not receiving a compass reading so I worked for a while to fix that with some voodoo magic.
Now, it is still acting crazy and while hovering will suddenly just drop and be very difficult if now impossible to recover.
It seems to only do it in GPS mode however atti mode seems to have a pretty decent drift to it as well that seems like more than just wind but I could be wrong.
I have the compass calibrated and within the 1600-1800 spec DJI calls out
I have done advanced calibration a couple times and still no luck and no indication from the lights anything is wrong.
Has anyone ever seen this before? It seems to fly alright when not hovering but if I just let go of the controls it goes crazy after a few seconds.
http://youtu.be/m38Q_ilTzPg
Thanks

 

[OI Photography]

First it was not receiving a compass reading so I worked for a while to fix that with some voodoo magic.
Thanks

1. Did you sacrifice a chicken or a goat? Common noob mistake.

2. (serious question) How cold and how humid was it where you were flying?

 

[motobtn]

I'm in MN... Not real humid but around 25F. It is definitely some of my first cold weather flying but I didn't think 25F is all that cold for the electronics or batteries. Am I wrong here?

 

[OI Photography]

I'm in MN... Not real humid but around 25F. It is definitely some of my first cold weather flying but I didn't think 25F is all that cold for the electronics or batteries. Am I wrong here?

The Phantom has been flown in colder weather than that, I was just guessing more along the lines of icing on the props or something that would gradually reduce the amount of lift produced. I guess it's possible the batt(s) you were flying with were more sensitive to cold than usual, but I haven't tested mine below ~35F

 

[motobtn]

It is interesting because the more weight I add the more obvious it is, ie gimbal. So maybe these batteries can't handle it or ? I have EProps on it and dual batteries and unfortunately this weather won't warm up for me to try warmer temps. I will wait I guess until we get at least mid 30s and see if it changes. Very strange though
Thanks for the replies!

 

[OI Photography]

It is interesting because the more weight I add the more obvious it is, ie gimbal. So maybe these batteries can't handle it or ? I have EProps on it and dual batteries and unfortunately this weather won't warm up for me to try warmer temps. I will wait I guess until we get at least mid 30s and see if it changes. Very strange though
Thanks for the replies!

You bet! And yeah I'd wait to see if it behaves the same in even slightly warmer weather. The fact that it's more pronounced with the more weight you add could indeed point to the batteries not being able to deliver enough current in those temps.

 

[acoll123]

I had the same issue yesterday due to ice on props - here is my post:

viewtopic.php?f=4&t=9486

 

[Byrdimaging]

It looks like it starts to spin when it drops. That looks like one motor is slowing down. Motors can also be effected by cold temps, it wouldn't hurt to check your CCW motors.

Note: It is still possible it's the batt or something else but it doesn't hurt to check. I use a microphone literally touching the motor mount screws record and compare them.

 

[motobtn]

Very interesting thought on the motor. Is there a good way to test or what are you thinking exactly.
I looked for ice but didn't really see anything so I don't think the props are icing up

 

[motobtn]

so I just used the Naza Assistant software to turn all four motors. Turns out M3 sometimes will rotate and sometimes not when I click the test button. Seems very hesitant and would make sense with the way it sometimes "spirals" down.
So, I replaced the motor and same thing.
Pretty much leaves me with replacing the board unless anyone else has any suggestions.
Thanks!

 

[OI Photography]

Pretty much leaves me with replacing the board unless anyone else has any suggestions.
Thanks!

Meaning the ESC? That's where I'd start next.

 

[motobtn]

Yup, referring to the ESC
Thanks, I guess I'll order one of those, just wanted to make sure I was on the right track.

 

[Ozzyguy]

Tell me. Are you're prop self tightening? I believe they aren't. Sounds like your props might be free spinning a bit and not transferring the torque from the motors.

 

[motobtn]

This is the phantom 1 but I have lock washers and my locks and definitely not slipping. It is very strange that the ESC works sometimes and then sometimes not, almost like it works with a certain voltage and above or isn't PWMing correctly at low voltage. I am ordering another and will try to swap to a different motor port and see what happens. I'll report back when I find out more.
I have best the hell out of this thing and recognize that. A phantom 2 will be on order as soon as I am confident with my flying skills with this which is my first rc flying machine ever

 

[Ozzyguy]

Yes I don't mean are you nuts slipping I'm talking asbout the props themselves moving. Are they tough enough not to slip