The weakest link
3960 28 2016-3-31
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Aeromirage
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A chain is only as strong as it's weakest link. How true......
I had a very minor crash last week putting the bird into a tree. (See http://forum.dji.com/thread-46847-1-1.html)
Initally, I thought my only damage was broken props but a few days later, I noticed the gimbal was not straight. It was leaning toward the side a little. It did not wobble as it swiveled, but remained on it's axis, which showed that the shaft of the pan motor was not bent. I removed the gimbal from the craft and rotated the top around and saw that it was rubbing in places. Then it broke.
     So, figuring that all bets were off as far as warranty was concerned, I took it apart. I was VERY disturbed at what I found. The top mounting plate, on which the entire gimbal, camera and lens is suspended from is made of a VERY thin piece of metal. Wether it is aluminum, magnesium, pot metal or some other allow is less important than the way it is designed. Aside from the thin-ness, there are 2 slots molded into it to pass the ribbon cable through. While these are entirely necessary, they serve to weaken it further.
     Part of the evolution of the design of any product is looking at it's weaknesses and making improvements in future production.
     Look at the Phantom 4. Is it any accident that the camera's tilt mechanism is supported on both sides? I think not.
     I opened a ticket with DJI support in the hopes that I may purchase a replacement part. Since I took it apart, I am pretty sure that warranty is null and void. But, for the sake of a part that could certainly have been designed with a little more strength, should I have to trash the whole gimbal / camera?
     I also hope that some of the forum's DJI employees will pass along to the engineering department that this part could become a problem, (Perhaps widespread?), and possibly change the way the part is made.
     Should a $2300 device be so delicately mounted to the aircraft. [Or $3599 if it's an X5R!)
     Here are some pictures:
a.jpg
b.jpg
c.jpg
2016-3-31
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njabinc
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Magnesium and actually the weaker of two different available formulas. It is nominally 1.1mm thick and as you've stated weakened by over 1/3 of the available surface being removed for ribbon cables. That in addition to the smaller opening having square corners which creates a mechanism for stress cracking. I know of replacements which are machined from 7075 aluminum and are redesigned which makes them 10 times stronger while only weighing 7g more. They also utilize far higher quality bearings. If you leave an email I will forward the information on how to obtain them. Either way i will caution that reassembly will be disastrous if you didn't index the retaining nut. Extremely important.
2016-4-1
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dobmatt
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njabinc Posted at 2016-4-2 00:05
Magnesium and actually the weaker of two different available formulas. It is nominally 1.1mm thick a ...


There's a recent conversation on this forum about minor flaws of X5/X5R camera suspension system design. It does excellent vibrations damping job, but it seems delicate and weak. After a few days of deliberation - from my point of view as an experienced mechanic and engineer - I've come up with conclusion that it doesn't really matter. The camera and gimbal are the most exposed and vulnerable elements of Inspire platform, as with any other systems with rising landing gear. These parts are first to be ripped off and damaged when things go bad. Never ending dilemma of every aircraft designer: how much of the payload will be sacrificed with heavier, stronger construction and bigger fuel tank? The Inspire lifting capacity is already heavily taxed by arms rising mechanism, leaving not much of the headroom for anything else. It's obvious that the weight (and durability) of any extra component added in evolution process must be compromised to maintain acceptable flying time. No, with today's technology available there's no radically better approach. Think about Charles Lindbergh, who get rid of not needed parts of the map to make his aircraft as light as possible ...
2016-4-1
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Farnk666
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No way I'd be spending my own money on a X5.
This is not the first instance of castings cracking, even without an impact.

Just not constructed/designed to a level commensurate with the asking price.
2016-4-2
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Aeromirage
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njabinc Posted at 2016-4-2 14:05
Magnesium and actually the weaker of two different available formulas. It is nominally 1.1mm thick a ...

Yes, I am interested in making it better.
I have sent you a friend request so I can email you.
2016-4-2
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Aeromirage
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njabinc Posted at 2016-4-2 14:05
Magnesium and actually the weaker of two different available formulas. It is nominally 1.1mm thick a ...

I see that you added me to friends list. How do I send you a PM?
2016-4-7
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njabinc
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Aeromirage Posted at 2016-4-7 17:56
I see that you added me to friends list. How do I send you a PM?

I sent you a PM if you don't see a notification simply go to your profile page as you should see it there.
2016-4-7
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dobmatt
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Believe or not, after my supposedly very smart comment here, exactly the same s#%*t happen to me ... During landing procedure sudden strong wind gust pushed my bird toward spruce tree ... 18 satellites above couldn't hold and - after trimming some branches and loosing 3 props - Inspire landed sideways on cushioning layer of needles and bark beneath ... Measured distance of free fall: 1.3 m ... The bird survived with no bruises, tested today successfully without gimbal ... But the gimbal itself is damaged in this very same fashion ... I'm sending the gimbal for repair to California DJI shop, curious what they'll say after examination ... 4+ ft fall, can you believe it!?

Apparently this is Inspire's Achilles heel, one of a few actually, to be honest ... Still, he was a hero ...



X5_gimbal damage.jpg
2016-4-7
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Aeromirage
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I have contacted DJI attempting to buy the part. Their reply was to send it to repair center. I once again asked if I could just buy the part, since I took it apart myself, I'm sure that voided the warranty. So, I asked again if I could buy the part. No answer after 5 days...................
I have read horror stories of people sending in items for repair, asking that an estimate be furnished only to end up having them skip that step, make the repair and then bill the customer. Not good business!! The thread that I read told of an Inspire repair that cost as much as a new complete setup.
I can't see paying labor on top of the parts since I took it apart and have a reasonable degree of mechanical aptitude. njabinc says he knows where to get the part but I can't seem to contact him.
Maybe I'll just unload it on ebay.......................... :@
2016-4-8
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Aeromirage
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dobmatt Posted at 2016-4-8 15:10
Believe or not, after my supposedly very smart comment here, exactly the same s#%*t happen to me ... ...

Sorry to hear of the same thing happening to you.
As you mentioned, it didn't take much to break it on mine or yours.
I don't think the part was designed minimally to save weight or material. I personally think it is just an oversight. A design flaw that will undoubtedly be changed at some point on future production.
2016-4-8
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dobmatt
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Aeromirage Posted at 2016-4-8 18:44
Sorry to hear of the same thing happening to you.
As you mentioned, it didn't take much to break  ...

No doubt, it's a design flaw we have to deal with. I've tried to get the part only as well from DJI, no way ... In this case, however, I tend to believe that DIY fix may be extremely difficult to perform. This is very complex and delicate machine with tricky assembly procedure ... note just the spiral winded ribbon cable inside. I'm skilled mechanic as well, and I will hesitate to mess with it without detailed instructions in English ... Let's wait and see how badly they will punish me for fix ...
2016-4-8
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Aeromirage
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dobmatt Posted at 2016-4-9 11:11
No doubt, it's a design flaw we have to deal with. I've tried to get the part only as well from DJ ...

I saw an example of your mechanical aptitude in that cool compass calibration spindle. Nice work!
I got an email (very detailed) today from njabinc explaining his efforts in re-designing the part.
I decided to unload the broken x5 on eBay but am thinking of buying the CNC machined part and replacing in in my new X5 so I can have a little faith in it.
Makes no sense to hang $2K from an eggshell...........
2016-4-9
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dobmatt
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Aeromirage Posted at 2016-4-9 18:47
I saw an example of your mechanical aptitude in that cool compass calibration spindle. Nice work!
...

So, you decided to abandon the idea of fixing X5 at DJI and going to purchase new unit instead? Ouch, that's truly heroic decision ... Would you share njabinc's concept with me, hope he'll not protest?
2016-4-9
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Aeromirage
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dobmatt Posted at 2016-4-10 09:47
So, you decided to abandon the idea of fixing X5 at DJI and going to purchase new unit instead? Ou ...

      I was blown away when I diss-assembled the gimbal at what I saw. There is an obvious lack of thought / engineering put into this key part of that gimbal assembly. Every other part in it has far better design elements and seems far better thought out. It is the wimpiest, poorest produced part in the whole assembly.
     DJI told me to send it to them for repair and I won't because I have heard plenty of horror stories of them not providing estimates and proceeding with ridiculous repairs and then billing the customer as much if not more than a new unit would cost.
     Their downfall... poor business practices after the sale.
     I am Not Bad rapping DJI here. Their products are outstanding, but refinements are a part of design evolution of any product. Especially Hi-tech items. Look at the changes that have been made to the way the props are secured to the aircraft. Their customer service after the sale need improvement. They admit that and are changing...... many reports say.
     I decided to sell the damaged gimbal on eBay. I thought it over and realized that I would never have full faith in it again. I have purchased a replacement X5 which is due to arrive on Monday. I bought an X3 to get by with in the meantime which I will re-sell on eBay, as it is a lesser camera. No F-stop, fixed focus = castration!! [Guess I am spoiled now!]
    I am still interested in the replacement / upgraded part and will likely replace it in the new gimbal to make it more durable. I see no problem in adding 7 grams to the aircraft. If maximum take off weight ever became a problem, I would probably lose the VPS as I never intend to fly indoors or that low to the ground.
     I am not trying to make it crashproof. I don't plan on crashing it... (Who does anyway?!!!).. but after having a look at the design of this part, I am worried that normal use and vibration could weaken, crack or break it. I have a strong feeling that it was already weak or even cracked when my mild crash did occur.
     Send njabinc a PM asking him for info. He sent me a lengthy and very informative reply.
2016-4-9
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Mike-the-cat
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Aeromirage Posted at 2016-4-10 10:59
I was blown away when I diss-assembled the gimbal at what I saw. There is an obvious lack of ...

Thanks for sharing and sorry to hear about the accident. Not to make excuses but some of us have had scrapes with trees on an Inspire Pro and escaped with an intact X5. In this instance, I was following a track at about 3m height with a nearly empty battery. At some point, a RTH signal was triggered and the craft ascended into the tree you see here. Fortunately, there was no damage to gimbal, craft or props. It was difficult to get the craft down though (4 m above ground) and the tree was not climbable. Eventually a passer by got hold of a long stick and managed to snare the branch and pull it down. Incredible.

Point is, its a judgement call how tough to make the materials. Even if the plate didn't break - would the loss of gimbal alignment be acceptable?

I think the pass through of cables saves their being snared and that might be a good trade off for slightly poorer mechanical stress. With the X5R, all the cables are buried in the gimbal arms. With the X5, the ribbon cable can be snared if one is careless.

Inspire in tree

Inspire in tree
2016-4-9
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dobmatt
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njabinc Posted at 2016-4-7 23:30
I sent you a PM if you don't see a notification simply go to your profile page as you should see i ...

Brother njabinc, need your help, but I've no idea how to PM you ...
2016-4-11
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njabinc
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dobmatt Posted at 2016-4-12 03:02
Brother njabinc, need your help, but I've no idea how to PM you ...

No problem. I sent you a friend request. Once you accept it you can click on my avatar and it will open the pm screen. Happy to help!
2016-4-12
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dobmatt
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njabinc Posted at 2016-4-12 17:39
No problem. I sent you a friend request. Once you accept it you can click on my avatar and it will ...

... call me stupid, I still don't know how to start private conversation ... I'm clicking on this scary blue skull, getting some space to write and than what? Gee, I'm getting old ...
2016-4-12
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dobmatt
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Brother Aeromirage, as for tonight things with repairing my gimbal are going surprisingly smooth so far... Send the unit last Friday noon by FedEx to California, get email confirmation of arrival Monday noon, today received the proposal ... I've been billed 315 USD (120 the yaw-axis component part + 195 labor) ... Together with FedEx expenses about 375 USD punishment ... I approved by paying via PayPal, they promise 1-2 weeks turnaround ... I'll pray now ...
2016-4-12
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njabinc
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dobmatt Posted at 2016-4-12 23:36
... call me stupid, I still don't know how to start private conversation ... I'm clicking on this ...

Not at all stupid. The forum is almost as easy to use as a firmware update.
2016-4-12
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Aeromirage
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dobmatt Posted at 2016-4-13 11:53
Brother Aeromirage, as for tonight things with repairing my gimbal are going surprisingly smooth so  ...

Hmmmm...... it would be very interesting to see what that particular part looks like after replacement.
     I wonder if any fortification / modification has been made to the design. Even if they thickened the flat base of it, maybe going from 1.1 mm to 1.8 mm, which would only add about 2 grams tops to the overall weight, would increase it's strength substantially.
     The more I replay this whole scenario in my mind, the more I think the piece was already weakened or even cracked just from 'normal' vibration / stress.
2016-4-13
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DroneAlps
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dobmatt Posted at 2016-4-8 09:10
Believe or not, after my supposedly very smart comment here, exactly the same s#%*t happen to me ... ...

We have the same problem with our X5 (crashed from a few meters up due to a random engine shutdown). Currently waiting for DJI to get back to us... will keep you posted on the outcome.
2016-4-13
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dobmatt
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Unbelievable! Two days after bill acceptance my X5 gimbal is apparently fixed and on the way home by FedEx ... Am I dreaming or what? ... OK, I'm not going to jump into enthusiastic comments before I receive the unit and test it thoroughly, but this is just too good to be true ...
2016-4-14
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dobmatt
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dobmatt Posted at 2016-4-14 17:47
Unbelievable! Two days after bill acceptance my X5 gimbal is apparently fixed and on the way home by ...

Today I've received my fixed gimbal back after less than a week. Everything seems to work properly! Bravo DJI NA, keep up good work!!!
2016-4-19
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Aeromirage
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DroneAlps Posted at 2016-4-13 20:12
We have the same problem with our X5 (crashed from a few meters up due to a random engine shutdown ...

Ever hear back from DJI?
Was the issue resolved?
2016-6-11
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steven.r.espino
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njabinc Posted at 2016-4-1 23:05
Magnesium and actually the weaker of two different available formulas. It is nominally 1.1mm thick a ...

I'd Love to get this replacement part!  Same thing happened to mine!

2016-10-4
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Aeromirage
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steven.r.espino Posted at 2016-10-5 12:10
I'd Love to get this replacement part!  Same thing happened to mine!

Check this out: http://www.inspirepilots.com/threads/x3-x5-gimbal-parts.11908/
2016-10-5
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fans87f0ac78
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Many owners of DJI ZENMUSE X5 have a problem with the pan axis (YAW), especially after the falls and not successful landing of the drone. I myself faced such a problem. I applied to DJI, but since I live in Russia and my camera has run out of warranty by that time, it was not possible to repair the suspension in DJI. I had to buy a new camera. And the broken remained on the parts ... A little later I began to look for different ways to eliminate the breakdown and a year later everything turned out! Hallelujah! Everyone knows that the company DJI takes a lot of money for its products, but few know why we pay so much? The bearing part of this three axial suspension of the so-called YAW axis (or else it can be called the wm610_gimbal motor), namely the part on which the whole camera hangs, is made of weak material at the factory, and the thickness in the most important place does not exceed 1.1 mm. (in the suspension of the camera X3 in this place, even 1.4 mm) So that's it! The part is complex and small with a lot of internal threads, and we learned how to make this core from an alloy of 6061 aluminum with a thickened wall of 2.6mm. So this part has become light and the most durable than it is produced from the factory. I hope now we can help all owners of DJI zenmuse X5 cameras fix their broken and problematic suspensions. And also replace the spare part on new and existing suspensions. This will strengthen the YAW axis state. Please contact us and we will help you subaru2010@ngs.ru.
Sending to the regions. Payment by transfer to a card or (paypal for foreigners).
2018-1-28
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fans87f0ac78
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Many owners of DJI ZENMUSE X5 have a problem with the pan axis (YAW), especially after the falls and not successful landing of the drone. I myself faced such a problem. I applied to DJI, but since I live in Russia and my camera has run out of warranty by that time, it was not possible to repair the suspension in DJI. I had to buy a new camera. And the broken remained on the parts ... A little later I began to look for different ways to eliminate the breakdown and a year later everything turned out! Hallelujah! Everyone knows that the company DJI takes a lot of money for its products, but few know why we pay so much? The bearing part of this three axial suspension of the so-called YAW axis (or else it can be called the wm610_gimbal motor), namely the part on which the whole camera hangs, is made of weak material at the factory, and the thickness in the most important place does not exceed 1.1 mm. (in the suspension of the camera X3 in this place, even 1.4 mm) So that's it! The part is complex and small with a lot of internal threads, and we learned how to make this core from an alloy of 6061 aluminum with a thickened wall of 2.6mm. So this part has become light and the most durable than it is produced from the factory. I hope now we can help all owners of DJI zenmuse X5 cameras fix their broken and problematic suspensions. And also replace the spare part on new and existing suspensions. This will strengthen the YAW axis state. Please contact us and we will help you subaru2010@ngs.ru. Sending to the regions. Payment by transfer to a card or (paypal for foreigners).
2018-1-28
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