Aeronavics / Droidworx SkyJib X4 Crashes Testing Failsafe

Rentakill

Rentakill

Member
Hi everyone,

Was out last week practicing for my OC, part of the test is testing your fail safes RTH.

I have a SkyJib X4, consisting of

DJI Wookong-M

DJI iOSD Mk II

DJI Bluetooth Datalink + 50 Waypoint Unlocked.

8 X T-Motors MN4014-11

8 X Carbon 15 X .5 Props

Droidworx Distribution Board

HobbyKing 40A ESC 4

Using Turnigy nano tech 8.0 Lipo's.

Flight Data files

https://www.dropbox.com/s/bzpaeljqlttmnyl/FLY094.DAT?dl=0
https://www.dropbox.com/s/62137p4oy6uswca/FLY093.DAT?dl=0

These are my gain settings

gains.png


At the time of flight I had 7 sats and completed pre flight home lock. Skyjib was flying perfect after 5 mins I tested the failsafe by turning the controller off. It instantly stopped powering and dropped to the ground, landing on its high impact dome.

Impact dome copped most of the damage, lost 4 props and yet to test all the electrical.

My concern is when I turned off the controller the UAV didn't even attempt to process what was going on. It just turned off and fell from the sky.

Any help in determining what went wrong, pilot error and any other reason why this happened. Have sent flight data to DJI to have a look at. Aeronovics have replied to my emails, my original builder who was based in Sydney closed shop :(.

I have over 30 hours flight time with this unit, never had one issue.
 

econfly

econfly

Member
Odd. My only guess is your receiver failsafe engaged (as opposed to the WKM failsafe), sent full throttle down to the WKM, and the WKM killed the motors. What radio / receiver are you using?
 


econfly

econfly

Member
I don't fly the DX8, but if it has receiver failsafe like the Futaba receivers do it would be possible to accidentally setup that failsafe to drop throttle to zero upon link failure (may even be the default -- no idea). That would produce the crash you describe. You can test this on the ground. Load up the WKM assistant software and see what happens to the throttle when you shut the radio off.
 

dazzab

dazzab

Member
Egads! My OC test is coming up and I have the same exact rig. I've used RTH and tested failsafe on the ground but never in the air. Do CASA really make you turn the Tx off during the test? I've never heard that before.
 

Carapau

Carapau

Tek care, lambs ont road, MRF Moderator
Sounds like that in your receivers Failsafe setting the throttle is set to zero- it must be set to over 10%. On the bench, power up the system, turn off your TX and see what the throttle does


Sent from my iPhone using Tapatalk
 

iceman

iceman

Member
dazzab said:
Egads! My OC test is coming up and I have the same exact rig. I've used RTH and tested failsafe on the ground but never in the air. Do CASA really make you turn the Tx off during the test? I've never heard that before.
Click to expand...
You will more than likely be required to demonstrate that your failsafe works as intended by turning off your TX however you may be given an opportunity to regain control to land once your rig is back over the departure point. Always check your failsafe in the assistant first but remember that it's a CAA requirement to ensure that the failsafe works.
 

vulcan2go

vulcan2go

Member
What spektrum receiver are you using - not all support a programmed failsafe where you can pre set the throttle position when power is lost to the receiver. You need to check that your receiver is set up properly for the failsafe to work. When configured you must check it by connecting to the DJI assistant and tuning off the transmitter - the throttle should show that the failsafe setting is correct.
 

Hexacrafter

Hexacrafter

Manufacturer
With Spektrum you must re-bind the RX with the TX set to all of the settings you wish to be when power is lost....
Throttle- 50%
RTH - set armed
Landing Gear- Down

Then confirm all of these in DJI assistant by turning off radio while connected to assistant.

I hope this helps....
 

Benjamin Kenobi

Benjamin Kenobi

Easy? You call that easy?
As above, receiver failsafe. You need to have the transmitter throttle at 50% when binding it to the receiver. You can test it on the assistant program by turning off the transmitter and checking that the throttle doesn't drop to zero.
 

Rentakill

Rentakill

Member
iceman said:
You will more than likely be required to demonstrate that your failsafe works as intended by turning off your TX however you may be given an opportunity to regain control to land once your rig is back over the departure point. Always check your failsafe in the assistant first but remember that it's a CAA requirement to ensure that the failsafe works.
Click to expand...
I here you, when I purchased my UAV I tested the fail safe straight away with out any issues. Not sure what has changed since then. Will check the controller against settings.

Just trying to find some expert help to get my baby in the air again. What a learning curve this industry has dished out, thank god for lessons learnt hehe.
 

iceman

iceman

Member
As has been pointed out already, go to the assistant and check that the indication goes into the failsafe area when your TX is switched off and check the throttle position, it goes without saying that the props should be removed (DO NOT MISS THIS STEP!!). If you didn't build the rig yourself or don't have much experience then make note of the correct prop configuration CW/CCW etc.
 
Last edited by a moderator:

Rentakill

Rentakill

Member
DX8 failsafe was wiped totally clean, not to sure how it happened. Still investigating :(

I do know how it happened, rebinded controller and not setting the failsafe up.

Crying as I type for such a silly error.
 
Last edited by a moderator:

Rentakill

Rentakill

Member
Thanks again multiforum gr8 support, final damage toll. New crash cage, must say did a gr8 job considering it handled the impact well. Maybe different with a full payload. Flight controller mounting plate, boom 410mm, Inner Boom 1205/0064.

Give myself a full refresher re binding/fail safe.
 

dazzab

dazzab

Member
Rentakill said:
Hi everyone,
My concern is when I turned off the controller the UAV didn't even attempt to process what was going on. It just turned off and fell from the sky.
Click to expand...
After reading this I was a bit concerned about my setup and of course wanted to ensure failsafe was working properly before my OC test which was scheduled for next week. Turns out that my test date was moved up a week and I had a lot of other things to deal with as well given that I was applying to have four copters and one fixed wing on my certificate. The weather didn't help either. Anyway, when I tested my failsafe yesterday (one day before the test) the same thing happened to me. Yep, the copter fell from the sky. Thanks to your post I was only a meter off the ground so no damage believe it or not even though it flipped on landing.

I was convinced I had the failsafe set correctly because the RTH worked fine. But of course, as described in this thread, I actually had the receiver set to do failsafe and in those settings the throttle was zero. Plain ignorance on my part. I know better but made a bad call. Forum user Bluerex was there and figured it out for me. We set it properly and it tested out fine. Unfortunately, I didn't have time for a test flight after going over the copter the night before my test. The gimbal was out of balance so it was flipping around during flight. It was also very windy and I may have even had a compass issue. All in all it was a bit of disaster. So I aborted the flight, landed and agreed to do the test again in a few weeks.

What you might find interesting is that the CASA examiner specifically told me that I was not required to turn off the transmitter to demonstrate failsafe and that I could demonstrate it by having failsafe on a switch instead. I had the impression this point was up to the discretion of the examiner but I don't really know. He also gave me the option to not do any of the test in Manual mode although you are required to switch to Atti mode as instructed while doing the test.

There is a fairly lengthy interview involved in the testing and at least that went well for me. So when I return I only have to do the skills test. That test really isn't that difficult and I've done it several times. It's designed to demonstrate you can control the copter and do basic manoeuvres. If you've done any flying at all it's not that hard. They don't care about the speed you fly at which is nice if you are flying a big beast.

Hope this helps and I'll let you know how I go next time.
 



fltundra

fltundra

Member
That's the nice thing about the SuperX. As long as you have ch6 to 100%. X will override all other channel commands from the receiver. As in throttle set to zero.
 

Rentakill

Rentakill

Member
Hello again, nearly got my skyjib back ready to fly again. Final issue I have is the ESC looks to be intermittently causing motor issues in testing as I purchased a new motor and the same thing happened. Easy fix I hope would be to buy mew ECU hobbyking blue series 40amp and flash with simonK. Can anyone think of any other alternatives....

Cheers
 

dazzab

dazzab

Member
I would avoid the SimonK firmware. Indeed I just stripped down an Aeronavics hexacopter in advance of my OC test to remove the HK blue series ESCs I had that were flashed with SimonK. I'm pretty sure they contributed to a flip on takeoff that happened on my first attempt at doing the OC test where one motor didn't come up to speed on takeoff. There have been reports of sync issues with the slower motors and SimonK firmware. But the real issue is that the SimonK firmware really provides no advantage for the larger copters using large slower motors so why bother? Stick with the stock firmware, get the programming board and make sure you change the battery type so they don't cut off at lower voltages.
 

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