Crashed today first time out of 9 flights

nattieman · Dec 25, 2015

Well I was at a relatives house today celebrating Christmas. I decided to bring out the bird and fly her a bit. It was sunny,no breeze and 43 degrees. I did the cold weather update this morning. I changed the props over to a new set of carbon fiber ones from Drone World, a present to myself as well as the DBS antenna upgrade. I have flown one since the DBS mod and it seemed fine.
Today I recalibrate the compass checked over the bird and used the auto take off. She went up really slow and I thought that it might be because I needed to reset my settings after the update. Anyways I few her up to 300 feet and no issues. I then proceeded to fly out 2,000 feet and ran into a signal loss. The signal faded to the point of RTH. As the bird came back I was able to cancel RTH and fly again. I flew around a bit with out incident. While returning to the take off point I few it almost overhead. I started to descend and all was well. It came Down slowly and got to about 100 feet and all of the sudden the bird began to wobble side to side vigorously. I tried to ascend and basically had no control of it. I turned off the RC and turned it back on and that didn't help either. The bird descended sideways and crashed into the ground then took off again and hit a tree branch causing it to fall again and crash. This time it stayed down prolly because it was upside down.
In looking over the yard sale I noticed the camera mount was broke. The camera wires were pulled out and a black wire had pulled out of somewhere. (Please help me figure that one out) and the housing separated. Anyways I've included some pics and would like some input on what I need to do to get this bird healthy again as well as could it have something to do with this latest "cold weather update"?

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nattieman · Dec 25, 2015

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msinger · Dec 25, 2015

That sounds like VRS. You should stick with OEM props.

nattieman · Dec 25, 2015

I am planning on that..... Worried about buying them off eBay. Should I be?

nattieman · Dec 25, 2015

Yeah I had watched a video on the replacement props too for the phantom 3 and how they should not have metal hubs. Unfortunately these did but I really wanted to see if they were quieter and better in any way.... Well I'm not liking this result. [emoji107]

msinger · Dec 25, 2015

All will be fine if you buy from a reputable seller.

msinger · Dec 25, 2015

nattieman said:
Well I'm not liking this result. [emoji107]

It's an expensive lesson to learn.

nattieman · Dec 25, 2015

You've got that right. I'm thinking I need to get help on a list. Should I open it all the way up? Or just enough to put the housing together?

msinger · Dec 25, 2015

It would probably be easiest to completely open the top. Here's a good how-to if needed:

nattieman · Dec 25, 2015

Oh ok thank you [emoji106]

Dirty Bird · Dec 25, 2015

VRS, no doubt due to the aftermarket props. I would stick with the factory props. Looks like you have a bit of repair work ahead. Sorry about your damages.

GreggC · Dec 26, 2015

Dirty Bird said:
VRS, no doubt due to the aftermarket props. I would stick with the factory props. Looks like you have a bit of repair work ahead. Sorry about your damages.

VRS,
Please elaborate.

msinger · Dec 26, 2015

GreggC · Dec 26, 2015

msinger said:
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Thank you.

buford · Dec 26, 2015

msinger said:
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Could a set of prop guards aggravate this effect? I have removable ones and don't always use them, but when I do I have to be careful about decent speed because of wobble.

msinger · Dec 26, 2015

buford said:
Could a set of prop guards aggravate this effect?

Yes. And, if you're seeing your Phantom wobble on descent, then you've just answered your own question. Don't descend with the stick in the full down position and you should be fine.

buford · Dec 26, 2015

msinger said:
Yes. And, if you're seeing your Phantom wobble on descent, then you've just answered your own question. Don't descend with the stick in the full down position and you should be fine.

I have to admit, I knew it, just wanted confirmation from someone else. Once I saw it start floating down like a leaf, I automatically started easing up on the decent, and flying forward slowly. When it had settled down, I continued the decent, but at a much slower pace. I started a thread awhile back about motor angle, and why they all look out of whack. Prop wash was the explanation I got, or stability on decent. I wont ask which theory is true, but I will be careful when decending, with or without the prop guards.

Dirty Bird · Dec 26, 2015

VRS = Vortex Ring State. The video posted in the previous reply describes it in detail. Basically it's where the air beneath your props becomes unstable from the prop wash & you lose lift. Applying power to climb only worsens the situation. You can generally avoid VRS by avoiding full speed straight down descents. Descend slowly or while moving in any direction so clean air remains below your props.The way out is to push the RIGHT stick fully in ANY direction to get out of your prop wash & back into clean air. Unfortunately when it happens people don't realize what is happening, react too slowly, or lack sufficient altitude to recover. I suspect the aftermarket props exacerbated the issue.

My Vision+ has the old 3.00 firmware that allows faster descent rates (I think 4 or 6 m/s). DJI reduced the max descent rate to help avoid VRS. In hundreds of flights, many including straight down full speed vertical descent, I have only once seen a VRS situation develop. Because I was at altitude & recognized immediately what was occurring, it never got to the point of the full on Death Wobble & I was able to recover by applying just a touch of right stick.

With DJI props & current firmware I doubt most pilots will experience VRS. I am a firm believer in stock factory props. If you have your heart set on carbon fiber, choose the real DJI CF props. Hope you get your bird fixed up quickly without too much expense. Looks like a reshelling is in order to make her look pretty. You may want to consider DJI or a good repair shop if you aren't familiar with working on this sort of stuff.

GreggC said:
VRS,
Please elaborate.

Dirty Bird · Dec 26, 2015

Prop guards causing VRS has always been a hotly-debated topic. Most VRS situations that I have read about here seem to involve Phantoms with prop guards installed. Some people love prop guards & swear by them. I think they are just additional weight, drag, and something to get in the frame of view. I view them akin to a bicycle with training wheels. JMHO.

buford said:
Could a set of prop guards aggravate this effect? I have removable ones and don't always use them, but when I do I have to be careful about decent speed because of wobble.

nattieman · Dec 26, 2015

Well this was a tough lesson to learn and I'm done with the cool aftermarket props. I'm sticking with DJI OEM. I agree with the VRS or DEATH WOBBLE, that had to be it. It was absolutely calm with no wind and I believe that to be part of the cause too.