Twitchy, erratic flight.

[Dj Brady]

Hey all, new to the forum and I look forward to learning all about my P2+
Got an issue...

I picked up some generic white props on Amazon.com the other day and now my bird is flying very erratically, not able to hold a position, twitching in the air and even wanting to ascend without any input on the stick. (landing is inherently difficult, as you could imagine).

I've performed advanced IMU and compass calibrations (in spite of the 'over-temp' warning in the IMU section) and the conditions persist. I have a set of OEM phantom 2 props on the way, but is this really a possibility? Can props screw with this thing that badly?

Thanks very much, in advance.

 

[EddieR0691]

I would check the pitch of your propellers, you may have mixed and matched 9443's and 9450's. Usually very small raised digits on the upper edge of the blade near the hub. You may need a magnifying glass (or readers if you're old like me) and good lighting.

You also may have some very unbalanced propellers. Google "balancing DJI propellers" for tips...you don't absolutely need an expensive balancing tool, a shish kebab skewer will work in a pinch.

So, yes, it is conceivable that your props could cause erratic flight. Especially if you are mismatched AND unbalanced.

 

[Dj Brady]

I'm inclined to lean more towards mismatched props. The video comes out smooth, so it's hard to imagine prop balance to be the issue. These were generic props from Amazon. Hopefully they're marked and I can determine if it's a mismatch.
I do have some OEM DJI props on their way. I'll try them out before I start panicking.
My biggest fear is a damaged IMU, but based on info from the Phantom Assistant software, nothing appears to be wonky.
I'm trying to see if there's any historical evidence of this twitchy flight behavior and a direct link, but that info is sparse, at best.

Thanks again for the info, so far.

 

[Dj Brady]

I checked my propellers and it looks like I have matching numbers (only differentiated by L and R at the end.
I did, however, determine that I have a solder break on my left rear ESC. I noticed at power up, sometimes my right rear light was flashing yellow and the left rear was flashing red. Other times, they would both flash yellow, normally, until GPS lock and then they would both flash green. I popped the cover and pulled the ECU loose from the mounting screws and the board consistently flashed the yellow and green sequence, matching the right rear. If I flexed the board opposite the pull of the screws (push down in the middle and pull up on the ends), the lights flash correctly. If I push down on the ends, the lights get wonky.
This doesn't seem to affect motor response when I power up the motors and push the sticks, but who knows what's happening in flight.
I have a new ESC en route.

 

[EddieR0691]

That's a good find! Was it a used quad? maybe crashed earlier. Could just be defective cold solder joints too, as you found.

 

[Dj Brady]

It was used and it flew fine until my incident with the pole, which is when the two changes happened.
1. Broke 2 props, so I swapped out with a full set of generic props
2. The Light pattern changed to something wonky, and recently determined it was the ESC.

The OEM props will arrive tomorrow. I'll try that, and if it still flies erratic, I'll replace the ESC as soon as it arrives.. if still no bueno, I'll be back, begging for more info.

Thanks again for the info!

 

[jwax]

Are you back to flying good, DjBrady? I'm new with Phantom, and found very unstable motor speeds when a switched to carbon fiber props. At first. After a few minutes, they stabilized. Does the brain of this bird have AI? It appeared to have adjusted to the new props after a few minutes.

 

[Dj Brady]

I got another set of generics (before I realized how much they can throw off flight reliability) and they slightly improved performance.
I just got my OEM blades in from B&H and I'm going to go fly in about 20 minutes. I'll let you know.
I'm betting all will be right in the world.

 

[Dj Brady]

Yep.
100% improved. Response is perfect, stability is rock solid. I learned my lesson.

 

[Air Ontario]

Always use OEM props. The bird will twitch sideways erratically and rise and descend 8-10 ft and won't hold a hover with cheaper aftermarket.

 

[Dj Brady]

Always use OEM props. The bird will twitch sideways erratically and rise and descend 8-10 ft and won't hold a hover with cheaper aftermarket.

^^^^^^^ Everything this guy just said.