DJI 30A Opto ESCs and Axi 2814/22 motors

[david.scarbrow]

Boris, thanks for that...I'm going to do that tonight...re-check everything as though it is a brand new install again...maybe it is something like I can't see the wood because of the tree. I can't fly it again until tomorrow and assuming the new props. turn up. If I* find nothing do you think it may be worthwhile putting the Turnigy ESCs back to experiment with ? I know it is more time lengthy thing to do but if the same things happen it sure is not the DJI ESCs. I might also add a couple of skid rail extensions in to either side to give me just that extra moment in time to shut down if it starts to flip...it might save a prop. or two.

 

[david.scarbrow]

It has taken me a few days but I checked (and double checked) everything in terms of sound connections, layout, set-up, etc., etc.. Prior to attempting to fly the craft again I built a small hash frame and fixed it to the landing gear as a way of providing a little more time for me to react positively if continues to play up. Istarte the craft up as normal and attempted to take off...I still have exactly the same problem...fortunately the hash frame did give me that extra second allowing for a standard controlled throttle/power down. I have now replaced the DJI Opto ESCs with the original Turnigy ESCs...guess what it seems to fly OK...well for about a minute anyway. What seemed to happen then is a power loss to one of the motors (I'm not sure which motor and I cannot currently film it) and at that point the craft came crashing to the ground, boom first. The end result is badly bent landing gear, a splintered prop, a motor ripped out of its monting and an unrepairable bent and twisted boom arm. I've already ordered a new boom (£70 inc P&P), straightened the landing gear, and replaced the prop. I've had it now on astationary test with 2 x 5000mAh batteries worth of time at around half throttle...all smooth and not even a single stutter....what the hell is going on ? This is becoming an extremely expensive hobby and where many things don't work as hoped for any extended periods of time. Do I now just bight the bullet, put it down to an experience and go find something else to do.

 

[BorisS]

david dont give up ! there is problem somewhere obviously and we will find it.

Please make detailed fotos of your build ! Showing how the ESCs are connected and the connection to the motors etc etc.

Maybe we find something there !

Boris

 

[david.scarbrow]

Boris, thanks for those words of encouragement but it truly is becoming a PITA for me. However my electrical engineering background tells me to find the problem anf fix it...the stuff that tells me to be careful is how much more money am I going to spend to get this craft airborn to carry out FPV.
I've just taken a number of photos and attached. you can see that I have already straightened up the undercarriage with no problems. There is also a photo that shows the motor that was ripped from its mounting hanging from the boom. The other photos are about Wookong-M component layout and limited views of power connections. The untidy nature of some of the signal wires is from me lokking to see if there is a problem in these areas.View attachment 3617View attachment 3618View attachment 3619View attachment 3620View attachment 3621View attachment 3622View attachment 3623View attachment 3624View attachment 3625View attachment 3626

 

[BorisS]

David don't misunderstand me on this. But i wanted to see your build so i know what i am at. You build is clean and its obvious that you know what you are doing ! I couldn't see anything that would worry me or could be the cause. This is not the issue but once you have the setup going, reposition your receiver never good to be placed in the arms and the antennas in contact to any material, landinggear antennas pointing downwards or upward is a good position.

In Foto nine you have on loose cable but I think you know what you are doing.

1. That its has something to do with the ESCs would be a very strange one since you tried two different sets now and the turnigy worked for some time in the flight.

But still who knows, check on the Turnigy ESCs now again.

A. All solder joints from the bullet connectors from the ESCs to the motors are a 100%. Take of the shrink tubing and double check them. Sometimes the joints come loose and the shrink tube hold the wire in place and also a connection is given under a certain flight movement than again not and the bird falls.

B. Check under the shrink tubing that the Cables soldered to the ESCs especially the PPM servos signal cables are not loose or hurt anywhere.

C. Please post your ESC settings. It could also be that in the case of the turnigy ESCs you have a low voltage cut of config that caused one of the motors to shut down.

D. ESC calibration i dont think that i have to mention again, you know !

2. WKM.

A. Please check all the Can-bus connectors of the WKM of every components if any of the pins or cable are damaged.

B. Completely re-flash update your WKM even if you are already in the last firmware and do all the settings new.

C. Completely get the WKM View Datalink module out of the game for the next couple tests.

In the worst case it is also totally possible that something is wrong with the WKM unit. But if you do all the checking and the problem is there again, you are already prepared to overwhelm DJI support with all the needed info that they wont start a back and forward game on what could be the fault except their components.

One more thing next test. I always do it that way i dont understand why all others go through the troubles of uncertainty. Just maidened one of the FPV birds I am building like this today. Take someone strong who should hold the bird overhead with a good grip. Take the throttle to hover that the person says yes now it would take of, but he should keep holding it for a full lipo drain. Test the responsiveness left right forward back etc. 7 10 15 min however long you lipos need to be down to 3.5 per cell under load. If that test was successful without any awkward behavior tries to flip etc. Than go for your next test normal flight. If something happens again while you test with the person holding it the person can give you a response what happened. Maybe even for security reason give the person holding the quad over head a possibility to do a fast lipo pull.

Boris

 

[david.scarbrow]

Boris, its good what bouncing around some ideas and thoughts does. There's loads of stuff in your post worthy of further exploration. The thoughts that are coming in to my mind is that the original problem was indeed the DJI ESCs and by replacing them with the Turnigy ESCs fixed it (it was really smooth to take off and fly, be it for just a short while). All I have done is get rid of one fault but added another it is just a coincidence that they are similar. Maybe the ESC connectors to the motors are too tightly bound with the zip ties placing undue stress on the connection(s). Along with your suggestions I will also replace the connectors with slightly longer 4mm bullets and tailor cut the cables to appropriate length.

 

[matthew.wright5]

I had/have the exact combination you were talking about, and flying 13"XOARs. My AUW (CX4) was around 2kg. I could get her to fly on EPP 1045 as well. Only stopped using the ESCs because one was behaving erratically and wouldnt spin up. The DJI ESCs are supposed to be programming free when used with WKM so unless your XCALC is bad, it should work OK. I would suggest trying smaller diameter props and reporting back. Have you checked your power harness for resistance?

 

[david.scarbrow]

Mathew, in the recent past and before I put the DJI ESCs in place (using Turnigy ESCs) I did try out 12 x 4.5 APC props but the performance of the craft was not very positive and it was difficult to fly. My aim is to eventually use 13" XoOAR props but not until these recent problem(s) are fixed. I have checked out the harness on a couple of occasions for sound connections and all seemed to be OK...I havn't metererd its overall resistive qualities though...perhaps that is something I should consider. I have replaced all the ESC/Motor connections with 4mm caged gold bullet connectors...they have a considerable amount more of contact area and looks to be a good move. The soldered connections elsewhere and to and fro the distribution board are also sound. I'm looking forward to my new boom arriving so that I can try and fly it all successfully again.

 

[david.scarbrow]

Boris, Mathew, Dave and indeed anyone elde who helped me in my thinking to fix these problem(s) I've experienced because guess what...iti is fixed. The new boom arrived from the France, bought new 4mm bullet connectors, re-used Turnigy Plush 30A ESCs, followed Boris's thinking and although a little tweaking need to be done here and there all is OK. Based upon Mathew' good experience with DJI ESCs and AXI 2814/22 motors I can only put the initialstart of my problems as an iffy DJI ESC...the following problems were, I believe bad connections and self inflicted. The lessons that I've learnt is not to rush 'things', check and double check 'things' and carry out all the configurations when something has been changed and/or upgraded. I think my next task will be to purchase 4 x Meytech 30A V1s and replace the turnigy s' with them.