Accident with Octocopter

[fgomezd]

Installed on my OCTOCOPTER the following equipment and electrónics:

Frame: KRAKEN 130 FOXTECH
Motors: Avroto LIFT 3520 400Kv
ESC: FLYFUN 60 A HOBBYWING

PARAMETER	OPTIONS	SETTING
BRAKE	OFF	ON			OFF
BATTERY TYPE	Li-xx	Ni-xx			Li-xx
Cut Off Type	Soft-cut	Cut-off			Soft-cut
Cut Off Voltage	Low	Medium	High		Medium
Start Mode	Normal	Soft	Very Soft		Normal
Timing	Low	Middle	High		Low
Music Li-Po Cells	D	C	B	A	NONE
Reserved Item	Option 1	Option 2			Option 1

<tbody>
</tbody>

Flight Controller: DJI A2 + iOSD II
Propellers: Carbon 1855
GIMBAL: EAGLE EYE BLG5D DSLR BL (FOXTECH)
Gimbal an Camera Control: FUTABA 10 CHG
CAMERA: CANON 5D MARK II
FPV Transmitter: FPV584F Plug and Play 5.8 GHz 400mW
Flight control Transmitter: FUTABA 14 SG

The purpose of the OCTOCOPTER is aerial photography with a CANON 5D MARK II.

I made 14 successful flights from April to July without the gimbal and the camera, but on July 23 in test flight with Gimbal and the camera, the OCTOCOPTER lost all power and fell from a height of 19 meters with serious damage to the CANON camera, GIMBAL and OCTOCOPTER.

I am evaluating the cost of equipment lost in the accident and at first estimated to be around usd $ 5,000.

I dowload the flight information from IOSD in which can see a sudden cut off of power to the motors. Would like to have a diagnose of the problem, because have to decide what to do to repair my equipment.

 

[Lanzar]

Hello,

ESc setings are totally wrong.
Battery should be NI and cutoff voltage low.

 

[fgomezd]

Hello,

ESc setings are totally wrong.
Battery should be NI and cutoff voltage low.

But the batteries are LIPO 6S.....

 

[dazzab]

I dowload the flight information from IOSD in which can see a sudden cut off of power to the motors. Would like to have a diagnose of the problem, because have to decide what to do to repair my equipment.

What was the battery voltage when the motors shut off?

 

[dazzab]

But the batteries are LIPO 6S.....

It's common to set the type to Nicad even with Lipos as it sets the cutoff level to a lower value. The cutoff value is there to protect the battery from being damaged by draining it too far. This works great in a plane. But with a multi rotor people would prefer a damaged battery over a crashed copter so if they need that little extra to keep it from crashing down then so be it. If you never drain your battery past normal then you'll never notice the difference between setting the ESC to Nicad but it's just another thing you can do to prevent issues.

 

[Lanzar]

It's common to set the type to Nicad even with Lipos as it sets the cutoff level to a lower value. The cutoff value is there to protect the battery from being damaged by draining it too far. This works great in a plane. But with a multi rotor people would prefer a damaged battery over a crashed copter so if they need that little extra to keep it from crashing down then so be it. If you never drain your battery past normal then you'll never notice the difference between setting the ESC to Nicad but it's just another thing you can do to prevent issues.

+1 @dazzab

Well this is why i am shocked that there were no serius or even death related incidents so far when so many homebuilds are done with no proper experience in tehnical part off the building the copter. Ppl just forget that 90% off the stuff came from airplanes and just adopted to MR's. I am sad to see ppl loose their money based on not doing enough research on what to buy, if it works to gether. Cause there are lots off esc and motors on the market that are not compatible or esc to dji ....
We have lots off clients that ask us the same stuff all over and i still see money ws safety goes 70/30 %. Hope new laws will prevent this and will require some MR licencing and inspection to be done prior.

 

[fgomezd]

+1 @dazzab

Well this is why i am shocked that there were no serius or even death related incidents so far when so many homebuilds are done with no proper experience in tehnical part off the building the copter. Ppl just forget that 90% off the stuff came from airplanes and just adopted to MR's. I am sad to see ppl loose their money based on not doing enough research on what to buy, if it works to gether. Cause there are lots off esc and motors on the market that are not compatible or esc to dji ....
We have lots off clients that ask us the same stuff all over and i still see money ws safety goes 70/30 %. Hope new laws will prevent this and will require some MR licencing and inspection to be done prior.

Dear Sr:

When the octocopter lose power the main voltage was 21.6 V, I have flight in other ocations having has a minimum voltage of 20 V that is 3.3V per cell and have good results, I think this thread is somethig not in the ESC, it must be in A2 flight controler, but good to know that I can set the ESC in NI so the damage is in battery and not in the octocopter. I have studied the stuff I brougth for about 7 months before I decided to buy. Yes I am not the most experienced contructor of octocopter, but do my best. Which ESC do you think is compatible with DJI?

Thanks

Francisco

 

[dazzab]

Dear Sr:
When the octocopter lose power the main voltage was 21.6 V, I have flight in other ocations having has a minimum voltage of 20 V that is 3.3V per cell and have good results,

21.6 is getting down there but I wouldn't think it would be enough for the ESCs to shut the motors off. I land at 21.5 and I'm pretty sure it would fall out of the sky at 20V. I think you are really pushing things going down to 20V. If I were you I'd just do some tests to check at what point the ESCs shut down. Should be easy to test. Then change the type to Nicad and cutoff to Low repeating the test again. This isn't the type of thing you want to be guessing about. Test it and come up with some hard data for your machine.

 

[Quinton]

Well to be fair, home builders do not really have a choice.
A lot of the "good" information is impossible to find as the "professionals" spend a LOT of money finding out what works and what doesn't, and that information is never shared because of the cost involved.
There has also been a lot of really dodgy stuff out there built by the so called "professionals" that should never be flown on a safety perspective.

It takes months and months of reading and research to try and get somewhere near knowing enough to build a good rig, but theres also a LOT of the small details out there that is really hard to find that could save your bacon (sometimes you find that out too late).
I am sure there are lots of people out there at the moment that do not know that they need to throttle calibrate their ESCs or have to program their ESCs for the best safety setup to ensure it does not cut off mid air.

The more information people share the better and safer it is for the home builders, but it is not in the professionals best interests to share such things as it is their livelihood.
I agree there should be some kind of safety inspections, especially for the heavier rigs, but who is to say what is right and what is wrong.
What Im really trying to say is that all the information is not easily accessible, it takes a lot of digging, research and learning from mistakes, unfortunately the mistakes can be costly and dangerous.

*FWIW I always land at 22V which is pretty conservative, I don't see a point in risking (1000s of dollars/Pounds worth) for another minute or so.

 

[gtranquilla]

First.... very sorry that you had a crash.

fgomezd, provides the type of information that should be reported with all crashes.
In this case there is no evidence that the DJI A2 was at fault IMHO.
I agree with Lanzar re: ESC settings and battery type selected in ESCs should be Nixx not Lixx.

Also it is easy to assume that some FC software, e.g., DJI Assistant software will do the ESC throttle range calibration for you.
However I am not convinced of this based on previous experience with Turnigy Plush ESCs that required individual throttle calibration directly thru the RC radio system or via a servo tester.

Hello,

ESc setings are totally wrong.
Battery should be NI and cutoff voltage low.

 

[Benjamin Kenobi]

Dear Sr:

When the octocopter lose power the main voltage was 21.6 V, I have flight in other ocations having has a minimum voltage of 20 V that is 3.3V per cell and have good results, I think this thread is somethig not in the ESC, it must be in A2 flight controler, but good to know that I can set the ESC in NI so the damage is in battery and not in the octocopter. I have studied the stuff I brougth for about 7 months before I decided to buy. Yes I am not the most experienced contructor of octocopter, but do my best. Which ESC do you think is compatible with DJI?

Thanks

Francisco

Seriously!!! 3.3V per cell!!! You are so close to destroying your lipo forever. 3.2V is the absolute minimum before a lipo is destroyed. You should be landing at a minimum of 3.7V.

Have you heard of the 20% rule? You should be putting back in 80% of the capacity of the lipo. So a 5000mah lipo you should put back in 4000mah when charging. How many mah have you been putting back in?

It sounds like a complete power failure to me, so check the resistance of your lipos, the wiring and connectors. Did you perhaps drop the throttle stick all the way down (below 10%)?

For once it actually doesn't sound like the A2 was at fault. :nevreness:

 

[gtranquilla]

Re: Which ESC is best......

That depends mostly on the motors you are using and there are many that are good although I have heard that those with Simon K firmware still have some compatibility problems with the newer pancake style motors.
In any case both the current and the voltage capability of the ESCs must be chosen correctly.
Also it is best to remain with ESCs that are the OPT type and exclusively use N FETS and not a mix of P & N FETS.

Dear Sr:

When the octocopter lose power the main voltage was 21.6 V, I have flight in other ocations having has a minimum voltage of 20 V that is 3.3V per cell and have good results, I think this thread is somethig not in the ESC, it must be in A2 flight controler, but good to know that I can set the ESC in NI so the damage is in battery and not in the octocopter. I have studied the stuff I brougth for about 7 months before I decided to buy. Yes I am not the most experienced contructor of octocopter, but do my best. Which ESC do you think is compatible with DJI?

Thanks

Francisco

 

[SoCal Blur]

I think we are overlooking the fact that there were 14 successful flights WITHOUT the gimbal or camera. Then the Gimbal and Camera were added resulting in disaster. This would cause me to suspect that the gimbal motors power connections were added to the main power feed of the Octo. I would consider that perhaps the connections were not secure and caused the power to become disconnected resulting in a complete shutdown. The other possibility is that you didn't take into account the additional current draw from the gimbal motors (and camera if powered from the main source) resluting in a much shorter flight time. The added weight would also contribute to a shorter flight time.

 

[fgomezd]

Thanks for your advice dazzab, I am going to make changes to the ESC, first to have it in NI and in low, but first will make some test to be shure were does the ESC cutt the power.

 

[fgomezd]

Benjamin:

I have always land at 21 V that is 3.5V per cell, when its been charge they reach from 8.000 to 8.500 mAh, they are of 10.000 mAh so the rule y no more than 8.000 mAh, I will have it in mind, but which will be the resistance of my lipos that will be desirable, what will be undesirable?

Thanks

Francisco

 

[fgomezd]

Socal Blur:

The gimbal motor had his own battery, and the gimbal was not conected to the FC.

Thanks

Francisco

 

[fgomezd]

Did you perhaps drop the throttle stick all the way down (below 10%)?

Benjamin: The pilot has experience and we are shure he didn´t.

 

[fgomezd]

gtranquilla, the ESC are HOBBYWING FLYFUN 60a OPTO and the motors are AVROTO LIFT 3520 400Kv, please let my know if the ones I use ".......exclusively use N FETS and not a mix of P & N FETS."


Please see http://www.hobbywing.com/product_show.asp?id=198

Thanks

Francisco

 

[fgomezd]

Installed on my OCTOCOPTER the following equipment and electrónics:

Frame: KRAKEN 130 FOXTECH
Motors: Avroto LIFT 3520 400Kv
ESC: FLYFUN 60 A HOBBYWING

PARAMETER	OPTIONS	SETTING
BRAKE	OFF	ON			OFF
BATTERY TYPE	Li-xx	Ni-xx			Li-xx
Cut Off Type	Soft-cut	Cut-off			Soft-cut
Cut Off Voltage	Low	Medium	High		Medium
Start Mode	Normal	Soft	Very Soft		Normal
Timing	Low	Middle	High		Low
Music Li-Po Cells	D	C	B	A	NONE
Reserved Item	Option 1	Option 2			Option 1

<tbody>
</tbody>

Flight Controller: DJI A2 + iOSD II
Propellers: Carbon 1855
GIMBAL: EAGLE EYE BLG5D DSLR BL (FOXTECH)
Gimbal an Camera Control: FUTABA 10 CHG
CAMERA: CANON 5D MARK II
FPV Transmitter: FPV584F Plug and Play 5.8 GHz 400mW
Flight control Transmitter: FUTABA 14 SG

The purpose of the OCTOCOPTER is aerial photography with a CANON 5D MARK II.

I made 14 successful flights from April to July without the gimbal and the camera, but on July 23 in test flight with Gimbal and the camera, the OCTOCOPTER lost all power and fell from a height of 19 meters with serious damage to the CANON camera, GIMBAL and OCTOCOPTER.

I am evaluating the cost of equipment lost in the accident and at first estimated to be around usd $ 5,000.

I dowload the flight information from IOSD in which can see a sudden cut off of power to the motors. Would like to have a diagnose of the problem, because have to decide what to do to repair my equipment.

I have taken in acount that have to change parameters in ESC, but I am sorprised the 8 ESC do no swich up? They are damage. I tried to reprogram them and the programming card does not startup. What do you guys have I to check up?

 

[kloner]

buying stuff from compentant dealers then asking them questions is the "work around" for not being educated or able to find the info..... it is multi rotor common to switch the batt type to ni..... you want the flight controller dealing with low voltages, not the esc cause they shut off one at a time.

if you can not talk to your esc's they either took a wallup of a hit or died in air which is your crash.

pretty sure the 14 pole 3520 want mid timing as well.