Safe speed to avoid motor cracks?

[Numone]

It’s likely DJI uses several vendors for the shells.
Not uncommon for their practices and thus quality to vary amongst them.

Hmmmm... given my knowledge of Chinese corporations and their procurement practices, I would doubt that very much.

 

[Numone]

If this was the case, all Phantoms would crack up but they don't.
If they all cracked, no-one would buy DJI.
I've only had 6 P3 & P4 series machines and flown them all hard with no cracking ever showing.
The only explanation for the cracking being observed in a minority of Phantoms is that the quality of the plastic or moulding varies.
Most are fine and deal with whatever is necessary but some batches have been released that were not.
This is also supported when you hear of a few users babying their Phantom or taking all sorts of supposed preventative measures and still getting cracks.

Exactly. The vast majority of shells are perfectly fine. Those that have cracked are probably down to either insufficient moulding flow, resulting in microscopic bubbles forming in the styrene which dramatically weakens the material and/or over torquing of the motor mounting bolts. I was lucky; before I even started the motors, let alone fly, I undid the bolts to affix prop guards. When I found probably 60% were ridiculously tight, I undid and refixed all of the bolts and used a tiny amount of Loctite 425 on the threads. Given how tight the they were, I suspect if I had flown before refixing them, it the amount of compression caused by the over torquing of the bolts would have resulted in huge stress on the plastic motor supports with a probable failure. Just my theory of course....

 

[N017RW]

Not sure nationality matters.
Single sourcing any component leaves your supply chain vulnerable to interruptions. Incidents such as fire, natural disasters, labor disputes, etc. could cause production disruptions.
I work in the plastics industry and we do not single source our resins, additives or equipment.

 

[Meta4]

Lets say just odd batches of P's are subject to cracking for whatever reason - what is best ? Ignore and hope you are one of the lucky ones and no cracks or take the cautious path and try to reduce the risk of them ruining your day ?

It's all very well to take what you presume will be preventative action, but there are quite a few theories about what causes cracking and what will prevent it.
Which one will you choose? It's going to be wasted effort if you back the wrong solution.
And wasted effort and unnecessary weight if your Phantom wouldn't have cracked up anyway.

Forums are very good at creating incorrect perceptions about the incidence of problems.
People with problems complain but people that have no issues don't make posts to talk about it.
There have been posts asking for people without firmware or cracking issues to report in and they have shown that the perceived widespread issues are nowhere near as common as you might believe.

It has been obvious that the design has a fundamental fault

Having had several Phantoms that never developed any cracking, it's not obvious to me that the design is flawed.
The theory of flawed materials fits the evidence better.

 

[solentlife]

It all comes down to personal preferences - regardless of what evidence / perceived reasons ... et al.

I have 2 P3's ... with one badly cracked and other with signs that it would have carried on without the plates. That's 2 ... one a P3S, other a P3P.

There's 8 in our club ... S's, A's and P's ... all show signs of cracks to varying amounts.

That's 10 against your 6 in just a small selection of people.

As I say - I do not say ALL WILL crack - but what I suggest is preventative action may as in my P3P case reduce the cracks appearing or spreading.

What is so hard about that to understand ? Not trying to be rude but I find it surprising that such a subject creates such argument.

Reminds me of all those who argued against Seatbelts in cars ...

You can still die in a car crash with or without a belt, but the number of lives saved outweighs the argument. I feel same about the plates ... number of arms saved by their use outweighs argument against. Their weight is negligible and does not affect flight time ... they have inner two screws and stand-offs to help support the arm at its weakest point.

Nigel

 

[Numone]

Not sure nationality matters.
Single sourcing any component leaves your supply chain vulnerable to interruptions. Incidents such as fire, natural disasters, labor disputes, etc. could cause production disruptions.
I work in the plastics industry and we do not single source our resins, additives or equipment.

Well, yes I guess potentially it does, but only if your RM supplier has poor business continuity and DR plans, in which case, one wouldn't contract with them in the first place. But I'm talking about production; as a purchaser of the end product, spitting production inevitably gives inconsistencies in the deliverable and quality control, operating methodologies; more generally pointless production meetings, drawing-up comparator data, additional audits, plus other administrative nonsense and of course, increased bottom-line costs as you've limited ones buying power. But, oddly, many "professional" purchasers think all this "post contract in life partnership management" helps justify their existence once the deals are in place.... If you need to micro-manage your suppliers - which is what this is - there isn't a strong partnership in place at all. Also, if the contract is large enough I might look to secure a tripartite relationship with your raw material supplier/s, to gain a leveraged shared discount. For that you'd get a longer contract with potential to extend. Obviously, all deals will have fully open book accounting.

 

[solentlife]

Oh Dear ! This is now reminding me of the countless discussions about Oil Products and their supply !!

One guy says - I will always use Shell ... another says I would never use Shell .... another Esso etc . etc.

Apart from limited additive addition to a brands volume - it gets sourced from so many that it loses its identity in fact. My job is to superintend oil shipments around the world ... that includes Civilian and Military ... during 'quiet periods' in various lands such as China - I like to know what goes on.

The raw materials market in China is wide open and not exclusive contracted. Second - even as I type China is reviewing / altering many aspects of Raw Material supply / production in light of environmental pressures. Its affecting not only those materials unfriendly but also safe materials as the facilities and productions using them come under the Govt scrutiny. Plastics industry in China will and has been no exception.

China is like Russia in many ways - there are no such animals as exclusive contracts ... yes they are written and signed - but that's where it ends. Sounds unbelievable - but its true. There are only a few actual producers in China that keep to such contracts ... as long as supply to them is steady.

Nigel

 

[N017RW]

All decisions or tactics have trade-offs. Since no one really knows the root cause it would seem there is variation somewhere.

 

[solentlife]

All decisions or tactics have trade-offs. Since no one really knows the root cause it would seem there is variation somewhere.

Of course ... so its natural that a "cure-all" is brought to bear. Bit like the 'band-aid' over a cut ... no idea why the cut, but it covers it.

Nigel

 

[Numone]

Oh Dear ! This is now reminding me of the countless discussions about Oil Products and their supply !!

One guy says - I will always use Shell ... another says I would never use Shell .... another Esso etc . etc.

Apart from limited additive addition to a brands volume - it gets sourced from so many that it loses its identity in fact. My job is to superintend oil shipments around the world ... that includes Civilian and Military ... during 'quiet periods' in various lands such as China - I like to know what goes on.

The raw materials market in China is wide open and not exclusive contracted. Second - even as I type China is reviewing / altering many aspects of Raw Material supply / production in light of environmental pressures. Its affecting not only those materials unfriendly but also safe materials as the facilities and productions using them come under the Govt scrutiny. Plastics industry in China will and has been no exception.

China is like Russia in many ways - there are no such animals as exclusive contracts ... yes they are written and signed - but that's where it ends. Sounds unbelievable - but its true. There are only a few actual producers in China that keep to such contracts ... as long as supply to them is steady.

Nigel

I wasn't talking about the RM supplier; I talking about the product producer i.e. the manufacturer of the DJI shells and my experience of buying goods from a chinese manufacturer.

 

[solentlife]

I wasn't talking about the RM supplier; I talking about the product producer i.e. the manufacturer of the DJI shells and my experience of buying goods from a chinese manufacturer.

No worries ... and I wasn't aiming at you .... just remarking and indicating that many in the street are unaware of commercial realities ...

Branding and advertising are powerful tools that cover a multitude of 'sins' !

Nigel

 

[Numone]

No worries ... and I wasn't aiming at you .... just remarking and indicating that many in the street are unaware of commercial realities ...

Branding and advertising are powerful tools that cover a multitude of 'sins' !

Nigel

Very true, Nigel.

 

[solentlife]

Seems Cracks are getting another thread ...

calling it a day with DJI

Nigel

 

[apollo64]

The plastic just seems to be the wrong sort (it's a bit like the plastic used to make yoghurt pots). I suspect that if you left the phantom in the box and never flew it you'd still get cracks on some

My PV2+ was riddled with it (not warranty covered despite being purchased from a UK DJI dealer) yet neither P3 I've had seem to suffer it (yet!)

That has happened with my P3, it had one hairline crack that i rubbed super glue into, barely flown it in month and now i have a second crack appeared same motor

 

[apollo64]

There's no connection.
Most Phantoms never develop any cracking at all.
All that I've ever had have never cracked despite flying at 35 mph most of the time.

seems to be a lot of this about lately, even see one pic where a motor came out of the frame in flight due to this

 

[solentlife]

But according to some - its a rare item to see .....

Yeh well ... it may be only a small % of total P's sold - but its still too many ......... but considering I know of 10 P's that have cracked out of 10 I personally know of ... seems not so small a problem.

Nigel

 

[Apilot101]

Call me lucky, I put braces on my P3 when it first came out, and have yet to have a crack. And I at times will fly wide open.

 

[solentlife]

Prevention is always better than cure ...

Maybe one of the lucky ones and will never have a crack ... but maybe one of the unlucky ones ... so who wants to take the chance for the sake of about $10 worth of plates and 20 mins work to fit them.

Nigel

 

[Apilot101]

When I purchase mine, there were many people complaining about cracks. So the following day I ordered braces, put them on immediately, and never looked back.

 

[MotorCycle-Man]

I have read all this thread about the stress in the areas of the Djs motors that cause the stress cracks......Now what do you recommend i have a near month old P-3 SE and i seen plastic reinforcements and i seen the Aluminum ones advertised ....what type do you like and recommend.....I want to be like Apilot01 and install them ! and how about a link to them too . Thank You all who help me.,,decide !