Flight instability

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Hi

Today I had some close range flying/shooting practice! I was flying some 3ft from the ground, and very close to trees and some old church. Since I had many preparations before making fly-byes, becose I was calculating the path and rechecking it all over again, not to hit something, I noticed my plane was really unstable in this circumstances. First of all, while hovering it shaked a lot, which i never noticed before, and when I moved it for some position corrections it moved a lot more than usual, and regulary loosing orientation and altitude, and acting "drunk" in a way.

First I thought it is becose of low altitude and possible ultrasound errors becose of grass/stone terrain below. But then I moved over the tarmac, and same thing happend again. It was calm, no wind at all, some 10-12C, sunny and very nice for flying.

I noticed the "update required" squared message uppon start up, but I updated the firmware two weeks ago. But then, since I was circleing around the plane trying to figure out what could it be causing this instability, I noticed pretty weard sound comming from one of the proppelers (I dont know which one), and upon restarting, I noticed an message about "proppulsion...." something, I noticed it too late, and it did not appear again.. so I thought maybe its the proppeler. I checked those thoroughly, but except some grass and bugs? juice, no damage of any sort was found...

I see new FW is actual, Ill update it later today, but it does not sound like a FW issue!

Any suggestions?

Thank you.
 
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Did you actually take the props off and do a really close inspection of the blades and the hub? Grass stains indicate that they have come in contact with the ground and you might be developing some cracks. If you have them, it might even be a good idea to try a new set of props. Even from a few feet up, having a prop come off and sending you bird into the ground can cause some serious problems!
 
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I noticed an message about "proppulsion...." something, I noticed it too late, and it did not appear again.. so I thought maybe its the proppeler.
IMHO, the message that popped up was most likely 'Propulsion output limited....' and further details and possible causes can be found in the threads from this search.

http://www.phantompilots.com/search/20339529/?q=propulsion+limited&o=relevance

...and you could think about doing an IMU recalibration (after you have updated).
 
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Ok, this message looks logical since my battery was not fully charged at the moment of starting up. But then it is nothing to do with in-flight instability...

I just did a quick inspection of the plane and found one of the motor legs (holders) pretty loose!!!! The whole body part which nestes the motor can be slighly twisted around its axis and the motor itself its not firm as other three??!?!??! I dont know how could that be. Nothing looks broken, no screws are missing... and yet, there is a small "wiggle" of the whole second half of that motor holder... oh boy..
 
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Ok, this message looks logical since my battery was not fully charged at the moment of starting up. But then it is nothing to do with in-flight instability...

I just did a quick inspection of the plane and found one of the motor legs (holders) pretty loose!!!! The whole body part which nestes the motor can be slighly twisted around its axis and the motor itself its not firm as other three??!?!??! I dont know how could that be. Nothing looks broken, no screws are missing... and yet, there is a small "wiggle" of the whole second half of that motor holder... oh boy..
Yes, I wasn't saying that the message was connected to your instability, just giving you information about it.

A loose motor could be the cause of shakiness though. It's possible that the bits where the screws go into, (which are not visible as they're on the inside of the shell) could have broken/broken away from the shell. The only way to tell is to carefully try to tighten up the screws and see if they grip. But if they do, don't tighten them too much or you may cause cracks in the shell later.

If you manage to tighten up the motor-mounting screws and you still have the same problem of instability, my second suggestion of doing an IMU recalibration (after any upgrade of FW you may decide to do) might sort that problem out.
 

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