DJI has confirmed that the aircrafts arms should not be loose or moving...

[The Editor]

Hmmmmm... been watching this thread with interest.

There clearly is an 'issue' here (well much the same as every product that DJI has released to date so they are consistent I suppose) however I think Ultra310x may have hit the nail on the head mentioning a thrust bearing.

In order for the Inspire to transform and allow the motors to lean out by a few degrees there has to be rotational movement within that collar with the shorter arm causing the rotation by virtue of it's shorter length.

I would like to be able to do a full tear down of this section of the craft to see how it has been engineered but it would appear to be similar to a rotor hub assembly seen on collective pitch helicopters. The inertial forces in this case being transferred through the arm to the thrust bearing. That being the case I wouldn't mind betting that within that assembly there is also a flange washer (or two) and a damping 'O' ring sitting next to it to absorb the forces and preventing the bearing shaking itself to pieces.

If I AM right and at this stage it's only an assumption based on building many multirotors and building/tearing down and flying too many helicopters I can remember, then those 'O' rings will have a life expectancy and WILL need to be replaced at specified intervals in order to maintain the integrity of the sub assembly.

Again, if my assumptions are correct then DJI are correct in saying that the nut in question should not be overtightened as this will cause the 'O' ring to become compressed which will diminish it's ability to absorb energy and shorten it's life expectancy. It could also cause the bearing to become much stiffer to turn and thus put undue stress on the transformation motor.

Of course, if DJI would stop playing 'Nanny' and give end users correct instructions on how much to tighten this nut we wouldn't be having these conversations.

I expect to see many more 'problems' in the coming days/weeks with this apparent design flaw/weakness/manufacturing QR issue.

My own belief is that DJI over worked the idea of getting a 'coolness' factor into the Inspire design (probably as a selling point) with transformation and this is going to be a weakness of the bird.

If someone want's to shout me down here then fine but I would REALLY like to see a complete teardown of that arm assembly.

 

[Chase]

Mark thank you for your post. I would be curious at the temperature that the 4 of you were flying at. I fly in cold temps and warm temps year round. Bouncing between Lake Tahoe and Las Vegas, I fly in both extremes.

Tahoe_Ed I'm one of the 4 and here in Connecticut I did a first flight this past saturday 1-10-15 at 11:30am it was 19 degree 9mph wind Sunny I will be doing another test flight this friday. I have not called DJI support on the issue yet because I wanted to get more flight done I also notice my first flight was logged and I was having issue with my IOS app doing a hard crash and reboot I deleted the app and reinstall but when I went to view my flight log is gone its not showing anymore but I have the video of the flight being done from the Inspire 1 and from 3rd person with camera recording.

 

[Quadpilot]

Quad - I recognize that there is not a firmware lock. My point was only that there COULD be a firmware lock and that is interesting. For example, if I were to apply and receive a commercial license to use my aircraft, and there was something like an aircraft maintenance check required every 50 hours, it would be pretty easy for DJI to set it up where I would HAVE to have my aircraft checked every 50 hours or risk it being locked. That is not the case for the P2 as the current firmware does not have to be up to date on the aircraft.

First of all, there is a flight lock if the firmware is not updated three days after activation of the app linking to the Inspire. At least, that's the message I got when I unboxed my Inspire and powered on.

On the hypothetical issue you raised whether DJI at some point might, could, would, should, or ought to lock the aircraft down after exceeding some time limit, I have no clue why that would be in DJI's interest.

 

[BaldEagle]

First of all, there is a flight lock if the firmware is not updated three days after activation of the app linking to the Inspire. At least, that's the message I got when I unboxed my Inspire and powered on.

On the hypothetical issue you raised whether DJI at some point might, could, would, should, or ought to lock the aircraft down after exceeding some time limit, I have no clue why that would be in DJI's interest.

Quad - in the interest of national security, DJI could shut them all down instantly. And it could be in DJI's interest to be sure that only aircraft that have updated firmware OR have been inspected after a certain number of flight hours OR whatever they wanted, to fly. They could tie in national standards per country if they wanted, to, right?

Do you get it now? I'm not saying it's bad. I'm just saying it is what it is. They have control to lock down my aircraft anytime they want.

 

[Quadpilot]

Quad - in the interest of national security, DJI could shut them all down instantly. And it could be in DJI's interest to be sure that only aircraft that have updated firmware OR have been inspected after a certain number of flight hours OR whatever they wanted, to fly. They could tie in national standards per country if they wanted, to, right?

Do you get it now? I'm not saying it's bad. I'm just saying it is what it is. They have control to lock down my aircraft anytime they want.

Let's agree to disagree and move on.

 

[The Editor]

Guys - can you answer a question for me please regarding all this firmware lock-out malarky?

Assuming you DO NOT have 3G enabled iPads and therfore your Inspire does not have access to the World Wide Wonder Web how can it check whther the firmware is up to date?

Similarly, if you deny access to the Interweb from your PC before you connect the Inspire how can it 'check back home' for updates?

If it INSISTS on connection to the outside world say every third day or something daft, then it makes the entire rig totally useless for remote location shoots!

 

[saltire69]

Firmware lock-out is a load of rubbish just go and fly you Inspire and forget about it .Its a quadcopter !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! not a commercial aircraft .
The next thing will be the Martians are coming to get your inspire .

 

[airdrone]

When I handled a prototype Inspire 1 at the launch event in November, I noticed that this nut was loose. So much so, that I asked a DJI employee if it was designed to be loose so it could be undone and the arms would come off for easier transport. As we now all know, the arms are not designed to be removed. I hope Tahoe Ed will monitor this for us and bring us updates on this issue (or non-issue!).

on my INSPIRE was a bit slack in this arms, bent bolts more firmly, and it is absolutely stable no, no vibration. -

 

[sheldrake]

Adam, DJI has stated that users should not mess with the fasteners on the arms. Some movement is expected and is normal. My feeling on the oscillation is that it is a prop or motor issue. The motors must be precisely balanced on the Inspire. It is possible that one of the motors is out of balance. If so, then the users need to contact the DJI 24/7 support lines.

I was speaking to a DJI rep about the loose arms and as i was holfing the bird one of the pieces of tape flaked right off the arm. The rep said it was not a problem. Has anyone read anywhere in the manual that it voids warranty? I did not read that anywhere. And as flimsy as the tape is on my bird, it will only take a few flights and the wind speed to blow off the tape

 

[nhirsch]

i smell a lot of fish (to use a nicer word) in this thread. the video showing the motion is excellent and anyone telling me that's normal is not going to be selling me anything and frankly looses credibility. If it were flexing like wings on a plane, that's one thing but the video indicated a harmonic frequency which we've seen since the first videos when the camera shook like a leaf. It's quality control, tolerance issues and poor design IMO. Is one supposed to buy an arm balancing machine now like a prop balancer?

 

[Tahoe Ed]

A correlation between what? Also how many units are out there now??

Temperature and oscillation. I have no clue about the number of units that have shipped but it is certainly larger than the units tested.

 

[Tahoe Ed]

Guys - can you answer a question for me please regarding all this firmware lock-out malarky?

Assuming you DO NOT have 3G enabled iPads and therfore your Inspire does not have access to the World Wide Wonder Web how can it check whther the firmware is up to date?

Similarly, if you deny access to the Interweb from your PC before you connect the Inspire how can it 'check back home' for updates?

If it INSISTS on connection to the outside world say every third day or something daft, then it makes the entire rig totally useless for remote location shoots!

My iPad mini is not cellular enabled and when I am connected via wifi I can keep my maps cached and my app up to date. There is no PC or Mac enabled Assistant. Everything is done via the App.

 

[Eliran]

Any news about DJI's solution on the vibrating arms???

 

[blade strike]

I hoping soon, it's a real easy fix.

 

[Eliran]

You mean easy fix? How to then?
This solution may not be that easy. . .




I ultimately fixed my Inspire (the one in the video). The problem is not the bolts as I had originally thought based on other video posts. The problem is poorly fitting bushings inside the T-connector joining the motor arm with the H-cross bar.

If you open up the T-connector you will find two bushings that should fit tightly around the motor arm. The bushings are not solid O's, they are C-bushings that are designed to compress to fit. The problem is that the recesses in the T-connector cover are too deep and do not apply enough pressure on the bushings to cause them to compress. On the bushings you will find small rubber strips. I cut small plastic strips of the same size from approximately 10mil plastic and put them on top of the rubber strips. Alternatively, you can replace the rubber strips with thicker rubber (like tire inner tube) This provided enough compression to fit the bushings.

Now, I can hold the Inspire by one arm and shake and there is absolutely no play or rattle whatsoever (and the oscillation is gone).

One word of caution, be sure you remove the connection to the thin stabilizer tube and test the compressed fitting to make sure the motor arm still rotates easily. If you lock this connection up you might fry the transformation motor.

Rob Suggs, Jan 18, 2015

 

[blade strike]

You mean easy fix? How to then?
This solution may not be that easy. . .




I ultimately fixed my Inspire (the one in the video). The problem is not the bolts as I had originally thought based on other video posts. The problem is poorly fitting bushings inside the T-connector joining the motor arm with the H-cross bar.

If you open up the T-connector you will find two bushings that should fit tightly around the motor arm. The bushings are not solid O's, they are C-bushings that are designed to compress to fit. The problem is that the recesses in the T-connector cover are too deep and do not apply enough pressure on the bushings to cause them to compress. On the bushings you will find small rubber strips. I cut small plastic strips of the same size from approximately 10mil plastic and put them on top of the rubber strips. Alternatively, you can replace the rubber strips with thicker rubber (like tire inner tube) This provided enough compression to fit the bushings.

Now, I can hold the Inspire by one arm and shake and there is absolutely no play or rattle whatsoever (and the oscillation is gone).

One word of caution, be sure you remove the connection to the thin stabilizer tube and test the compressed fitting to make sure the motor arm still rotates easily. If you lock this connection up you might fry the transformation motor.

Rob Suggs, Jan 18, 2015

So you're saying that wasn't an easy fix? It will just require a thicker piece of silicone. Hopefully soon, end users will be able to do this.

 

[Eliran]

Yes, a simple thicker piece of silicone, but, to get there you have to face the fact that you have to adjust the swinging arms. I may be mistaken or adjusting the up and down arms may be hard to do?
Sorry if my english is not that good.

 

[sdjackaerial]

I'm glad you've got the knowledge and skill to take this on. Pretty impressive, really.
Personally, I can't *imagine* tinkering with this machine. I really thought & still think that it should be completely ready to fly without going all "hobby shop" on it. I didn't build this..I paid crazy $$ for it..know what I mean?

 

[thumpinhard]

ok,when i first got mine i noticed the nuts were not equally tight and the arms moved back and forth quite a bit. i saw the tape and slightly tightened the one that was the tightest and the arms were still wobbling around loose. i did a search and found a video where someone had removed the plate on the side and put a thin spacer in between and it made it solid. HOWEVER, you must remove the bolt on the lower arm to make sure it still moves freely..very important! otherwise when transforming it will bind the worm gear. when taken apart you will see a small flat rubber over the bushings. i added a very small thing piece a a nylon squirt bottle and tested it by hand,it was sold but seemed to bind a little when rotated. i cut the piece smaller and tested it again..it took three trys on one side and two on the other but now the arms move front to rear (due to the loose nuts) but NOT side to side. i checked once more with the lower rods disconnected and it had slight resistance and no side to side movement. mine has not vibration now and flys fine. i did have to move the tapes to drop the side plate so i am sure Dji would say my warrantee is void..so do this at your own risk. i am an inventor and a technician and am confident that this is a good fix and do not suggest tightening the nuts as in the above video..it did not help mine. the issue is side to side movement,not front to rear.

 

[aprilmedia]

Fix for this issue - Not as it seems!!!

OK, so we have our new inspire which is fantastic except we also had the arm shake issue which is now fixed as follows......
A word of warning though as some 'quick fixes' shown on line are not applicable, or even the right fix and could damage it.

The 27mm large hex nuts on ours will not tighten. It's as though they've been glued in place. Maybe a later mod by DJI on newer models, but having tried thinking this was the issue, I was in danger of doing some damage having looked closer.

So, having taken apart the mid clamped section which the arm runs through, the problem becomes apparent that its nothing to do with the outside nut (on our model at least!). There is no play horizontally in our model. It's set correctly. The issue is to do with the 2 Collets that the arm runs through which when clamped down with the 8 allen bolts should tighten around the arm enough so there is no play, but not so much that it over tightens movement to restrict the landing gear movement and strain the motor.

To do this, (voiding ((allegedly)) your warranty, but hey, that's half the fun and the rush!) we simply opened up the box by undoing the 8 bolts, and also unattached the motor arm, removed the rubber strip on top of the metal collet, cut 2 strips of insulation tape the same size as the rubber strip and stuck them one on top of each other and stuck it on to to the metal collet and put the rubber strip back on top. repeat for the other side and then tighten up the 8 bolts as you would a car cylinder head (i.e don't do all of one side first, do diagonals to ensure even distribution so it bolts down squarely) and reconnect the motor rod arm.

The arm should now still move freely, yet with no play at all. If its too tight then undo and just put 1 strip of insulation tape on, and if its still too loose put more on. We tried 4 at first but was too tight.
Repeat for the other 3 collets.

Hey presto - all wobble and jello now totally gone. I should have made a video, but hopefully the above is clear. Its really easy and took about 1/2 hour in total.

Hope this helps and gets you re-inspired!