Phantom 3A engine on fire !

[ALEX_S]

After reading about the P3s falling out of the sky I decided to share my experience with a brand new Phantom 3A a couple of weeks ago:
Shortly before going on a holiday I purchased a P3A, updated , calibrated, charged batteries, etc.
Took it out into the backyard for a test flight. Started the engines and took the bird to about 4 meters, let it hover for about 2 minutes, then take it up to about 14 meters, let it circle over the house top, return and land, switched the motors off.
Happy with everything obviously working perfectly I started the engines again and took the bird up to about 14 meters flying it around a bit. Up, down, left, right.
Not quite sure if it was imagination but moving the bird to the left felt suddenly a bit different than moving it to the right. So I took it down again and let it hover in front of me at about 3 meters height. Suddenly a very loud screeching noise from the Phantom, massive amounts of white smoke coming from one engine and it crashed immediately into the ground. It landed on the side blocking two props to spin, the other ones were still sort of spinning and I had to pull the battery to switch the electronics off. No reaction to the remote control switch off command.
The engine was still smoking for a while.There was no further damage to the craft except the copper winding of the engine was black with the clear varnish burnt off, brown burn marks on the propeller and the screws holding the motor to the frame did melt all the plastic around them !
Total flight time to disaster : 9 minutes.
The shop reluctantly replaced it with a new one. I had to fill out the dji form and sent the flight log to dji.
My engines were the old engine type by the way.
In regards to the cracks in many frames: if it is around the screws holding the engines I do believe they are mainly heat related stress cracks. The old engines and screws get fairly hot for some reason, may be only in some batches which could cloud the overall picture a bit.
There is a reason why new engines were introduced.
The replacement P3A also with old type engines has flown so far without any issues . But now there is always a constant worry that something is going to fail again. This is not my first drone, I have flown all models from the Phantom 1, 2 vision, 2 vision plus and a German Hexacopter carrying compact and SLR cameras. I am flying a lot over water and the first time since I am flying drones I am worried it will fall into the ocean. This is my very personal opinion but there is something unreliable in the electrical system of the P3 and its not loosely fitted batteries like many suggest.
If similar failures would occur in cars, these cars would need to be recalled by the manufacturer. Falling drones are extremely dangerous, fullstop. If this trend continues with falling P3s class action like legal action against DJI might be required. I do hope, it will not be necessary.
I was planning to sell my reliable P2 Vision plus. After this experience and seeing on the forum that quite a few P3s fall out of the sky for still unidentified reasons and airframes cracking I think I am better off keeping it as a backup.

 

[bbfpv]

Statistically speaking, the failure rate of the P3 series is significantly lower the the V and V+. You got a lemon, plain and simple.

 

[4wd]

I haven't noticed the motors getting hot at all, they are rather well ventilated so it's hardly surprising.

While there's no doubt an engine failure will result in immediate falling from sky, this seems to be a pretty rare occurrence which suggests they are mostly astonishingly reliable.
The P3 has been a huge seller and from the reports on here seems like maybe 2 or 3 incidents per week.

 

[nickyb]

Maybe that is why the new style motors have the grill/heatsink on the bottom to better dissipate the heat.

 

[Patrick]

Statistically speaking, the failure rate of the P3 series is significantly lower the the V and V+. You got a lemon, plain and simple.

what kind of data do you have on this?

 

[bbfpv]

what kind of data do you have on this?

From what I've read, the conservative estimate of DJI units sold in 2014 was approx 400k worldwide based purely on reported revenue. A DJI rep said they had sold 500k by June of this year. Since the P3 wasn't out until this year, it's a safe assumption that the majority of 2014 drone sales were of the P1 or P2 model. Comparing those numbers with the number of "fell from the sky" or "flyaway" accounts on the various phantom forums strictly for the P2. Now compare the number of "fell from the sky" or "flyaway" posts for the P3 vs over 500k P3s alone (by June), I think it's safe to surmise that the new model is significantly more stable. Albeit not very scientific, but trying to be scientific w/o hard data is obviously not possible. However, any reasonable person would probably agree.

 

[Patrick]

gottcha, i was hoping you had official numbers to quantify.

 

[aburkefl]

From what I've read, the conservative estimate of DJI units sold in 2014 was approx 400k worldwide based purely on reported revenue. A DJI rep said they had sold 500k by June of this year. Since the P3 wasn't out until this year, it's a safe assumption that the majority of 2014 drone sales were of the P1 or P2 model. Comparing those numbers with the number of "fell from the sky" or "flyaway" accounts on the various phantom forums strictly for the P2. Now compare the number of "fell from the sky" or "flyaway" posts for the P3 vs over 500k P3s alone (by June), I think it's safe to surmise that the new model is significantly more stable. Albeit not very scientific, but trying to be scientific w/o hard data is obviously not possible. However, any reasonable person would probably agree.

As a former working statistician, I'd say your reasoning is sound. Additionally, some of the true "fell out of the sky" problems can sometimes be tied back to an ESC instead of an engine. I think if you compare a "fell out of the sky" event due to an ESC vs. a motor failure - they both look pretty much the same.

 

[RedHotPoker]

I think the sky will fall, is more likely than my Phantom 3 Pro' will. ;-)
But that is only my personal opinion, from the awesome flights it has provided me with. The sky is the limit though. Hehe

RedHotPoker

 

[olof Ekbergh]

Brushless motors and ESC's are very reliable, but some are defective and fail.

I have flown tens of thousands of hours in MRs and traditional Helis as well as model airplanes.

I have about 40 RC planes that are electric 10 helis and 5 MRs. I also have a bunch of nitro models.

Out of all those I have had 2 ESC burn outs and 1 motor fail. I am not counting crashes, everyone flying 3D will have those.

My point is a small percentage of ESC's and Brushless motors will fail. It is four times as likely that there will be a failure with 4 motors and 4 times as likely to have an ESC fail. So that is 8 times as likely to have a motor stop in a quad, 12 times as likely in a hexa. So there will be a number of failures. These are just model aircraft and fairly cheap ones at that.

In some ways these are simpler no servos and much fewer moving parts than Heli and fixed wing models. But electronically they are way more complex.

I think to keep things in perspective. There are far fewer crashes with DJI MRs than regular RC aircraft. A new pilot in RC hobby will typically crash a few dozen planes just learning to fly. This is getting to be less so as gyros are making their way in to RC planes as well, and by learning on simulators.

However the big difference is these MRs are flying everywhere, so crashing is dangerous. Most RC planes only fly at AMA or similar fields with lots of clear fields around, or woods, but unpopulated areas. And out of necessity we stay very close.

Fly safe and have fun.

 

[Meta4]

After reading about the P3s falling out of the sky ...
In regards to the cracks in many frames: if it is around the screws holding the engines I do believe they are mainly heat related stress cracks. The old engines and screws get fairly hot for some reason, may be only in some batches which could cloud the overall picture a bit.
There is a reason why new engines were introduced.
... After this experience and seeing on the forum that quite a few P3s fall out of the sky for still unidentified reasons and airframes cracking I think I am better off keeping it as a backup.

Maybe that is why the new style motors have the grill/heatsink on the bottom to better dissipate the heat.

It's repeated threads with flawed reasoning and incorrect statements being treated as fact that help perpetuate this myth.
In a healthy, normal P3 the old motors don't run hot. If yours are hot, you have a problem.
Motors on the two P3s that I have flown (several hundred flights) get barely warm.

Forums are very effective at spreading rumours and perpetuating myths and this old hot motors is a good example.
It's been suggested to me that this thread is proof of a heat problem: Cracking the P3 crack | DJI Phantom Forum
But reading the thread shows exactly the opposite, particularly this post: Cracking the P3 crack | Page 2 | DJI Phantom Forum
The original motors in a P3 run around 38°C .. and for comparison, body temp is about 37°C.

The reason for introducing the new motors might have been because they were more efficient, cheaper, old ones no longer available etc etc .... but it WAS NOT because the old motors run hot.

 

[ALEX_S]

It's repeated threads with flawed reasoning and incorrect statements being treated as fact that help perpetuate this myth.
In a healthy, normal P3 the old motors don't run hot. If yours are hot, you have a problem.
Motors on the two P3s that I have flown (several hundred flights) get barely warm.

Forums are very effective at spreading rumours and perpetuating myths and this old hot motors is a good example.
It's been suggested to me that this thread is proof of a heat problem: Cracking the P3 crack | DJI Phantom Forum
But reading the thread shows exactly the opposite, particularly this post: Cracking the P3 crack | Page 2 | DJI Phantom Forum
The original motors in a P3 run around 38°C .. and for comparison, body temp is about 37°C.

The reason for introducing the new motors might have been because they were more efficient, cheaper, old ones no longer available etc etc .... but it WAS NOT because the old motors run hot.

In DJI's own words on facebook:

"New 2312A motors are more stable and balanced compare to the old ones."

There are probably different ways to read it. I do read in the sentence that the old engines are not that stable and balanced
compared with their replacement and it was one of the major reasons the old engines got replaced.

 

[Meta4]

In DJI's own words on facebook:

"New 2312A motors are more stable and balanced compare to the old ones."

There are probably different ways to read it. I do read in the sentence that the old engines are not that stable and balanced
compared with their replacement and it was one of the major reasons the old engines got replaced.

It's meaningless marketing language implying that the latest product is even better.
There is nothing at all unbalanced or unstable about the old motors.

 

[nickyb]

I said 'maybe' as a logical conclusion to having these 'vents' at the bottom. I think my statement was reasonable in the context of the original text of this post. Products are changed for a reason, not all consumers are aware of the reasons why. Sure your P3 has had many long flights without an issue and I'm sure many pilots have, its a well designed product. But all technical devices evolve with time and simulations of these motors may, I say 'may' have caused DJI to re-design the motors, and not just for 'increased production reasons' which in my view is rubbish, especially when you consider re-tooling of production, looming, re-classification etc etc.

Being lead designer of aero turbo-jet propulsion for many years I come across these aspects almost everyday in my field of work, including from the great engine manufactures such as Rolls Royce and P&W.

My 2 pence worth.

 

[ianwood]

If the "old" motors were somehow materially defective, we would be seeing A LOT of these reports. This is but one. Sounds like a bearing failure. If you have a decent crash and one motor takes the brunt of it (common), there's a reasonable chance the bearing is compromised.