S800 Major Crash - The spin of death

[junanata]

Did you solder something on the motors/ESC's ?

This solderpoints are thin like paper, and if you don't watch out and soldering is too hot, they come off the circuit board together with the motor wire and the solder.


Chris

Chris, yes we did to the ESC. We had to replace a few arms resulting from the FOD experience -- yes we have been through it all -- we have a while back. Now that you mentioned it, I guess I might have to go back and make sure all the points are well soldered.

As regard the OP, I agree it seems likely that the loose cable probably was the cause (or at least the primary cause), rather than the result, of the crash. junanata, can you provide any more detail (or a pic) of the 'loose cable'? That might help distinguish fatigue-related breakage (away from solder joints) from solder point failure for various possible reasons. Were the connections 'factory stock' or were there post factory changes made?

Steve

Steve, I will post it when I get back to the office Monday; everything is at the office. The connections were post factory changes.

 

[ProPilotWannaBe]

Chris, yes we did to the ESC. We had to replace a few arms resulting from the FOD experience -- yes we have been through it all -- we have a while back. Now that you mentioned it, I guess I might have to go back and make sure all the points are well soldered.

junanata, so that we can all collectively learn from this, can give us additional info? Like how long ago and how many flights ago was the soldering done on this motor/ESC? Can you tell if the pad is on the wire or still on the ESC? Does it look like a cold solder issue? From your answers, it might help us that have replaced arms to come up with a maintenance routine by which we may have to routinely check soldered ESCs. Thanks

 

[ProPilotWannaBe]

Yikes, there's some serious 'experience' being gained. BTW, which was going 30 mph, the car of the s800? If there were any particular lesson's learned that you care to share, I'm sure we'd be interested. If we learn for both our own and others' misadventures, it makes it harder to come up with new failure modes. Well that the hope anyway.

This was back when I had just upgraded from my F450 to the S800. It was basically a culmination of two issues. First and foremost, I just wasn't well versed enough in Manual mode, especially with the added power the S800 had over the quad. But then couple with the fact that I had just reprogrammed my transmitter for engaging Failsafe, and must not have triple checked my changes well enough. But there was a channel mix I missed based on a switch I never use, and the WKM was now in Manual, and I didn't realize it fast enough, and I wrestled with it for about 40 seconds before it came flying in on low full speed swoop right into my parked car (of all the things in this wide open field I s at). So bottom line, inexperience. It's one reason why I push for peeps to learn to fly all modes... I still can't say I'm proficient at Manual mode, but I practice it regularly so that at least I'm not freaked out by the power and sensitivity to the control inputs. (... Long story made a little shorter...

And now... Back to our regularly scheduled programming discussing junanata's incident...

 

[jhardway]

Thanks for the well wishes guys. jhardway you are right and also just as I suspected; one of the motors failed. We opened it up and found one of the cables going from the motor to the ESC was loose. I don't know if it was loose before or after the crash; but the way it spirals down it looks like one motor was out as seen on the video below. The thing is it shouldn't fall down fast like that should it? I know we have the weight of gimble but if you look at the second half of the DJI video, they also have the copter loaded and it doesn't just drop down like that. It makes me wonder if it is a wookong error causing the copter to drop and the cable got disconnected from the impact; or if it is a result from a combination of failed motor and a wookong failure maintain control.

junanata

When it comes to flying the copter when a motor goes out, I feel that its more about having a balanced copter over the weight, if you look at the vid when they did load the s800, notice that the weight they adding is on the legs equally centered, and more importantly the battery, is located directly in the middle under the copter not to the aft like it would be with a Zemuse attached, If they are so confident with the ability to fly the copter with a motor out and you are trying to sell them, why not show it in a real world scenario, like having a motor out with an operational zemuse, along with a full size battery.

At the end of the day, I am convinced from the videos, and with that said I have not seen anything online showing a copter making it down, which I would think if someone has had that happen. They would definitely show it, I would !!

Best wishes with everything and hope you get up soon

 

[junanata]

junanata, so that we can all collectively learn from this, can give us additional info? Like how long ago and how many flights ago was the soldering done on this motor/ESC? Can you tell if the pad is on the wire or still on the ESC? Does it look like a cold solder issue? From your answers, it might help us that have replaced arms to come up with a maintenance routine by which we may have to routinely check soldered ESCs. Thanks

Pro, I will post some pictures and give you some more info when I am back to the office.

 

[junanata]

junanata

When it comes to flying the copter when a motor goes out, I feel that its more about having a balanced copter over the weight, if you look at the vid when they did load the s800, notice that the weight they adding is on the legs equally centered, and more importantly the battery, is located directly in the middle under the copter not to the aft like it would be with a Zemuse attached, If they are so confident with the ability to fly the copter with a motor out and you are trying to sell them, why not show it in a real world scenario, like having a motor out with an operational zemuse, along with a full size battery.

At the end of the day, I am convinced from the videos, and with that said I have not seen anything online showing a copter making it down, which I would think if someone has had that happen. They would definitely show it, I would !!

My friend, I agree.

Best wishes with everything and hope you get up soon

It has been a few days now, we have not heard anything from our guy Robert at uavproducts. He too is probably trying to get a hold of DJI. Looks like it's going to be a while before we are up again.

 

[junanata]

Guys here are some pictures of the ESC. I hope it helps answer some of the questions you have. Pro, we had our FOD experience back in September of last year. I don't remember exactly how many flight we have since then. If I have to guess I would say it's around 50-70 flights.

View attachment 13258View attachment 13259View attachment 13260

 

[deluge2]

Guys here are some pictures of the ESC. I hope it helps answer some of the questions you have. Pro, we had our FOD experience back in September of last year. I don't remember exactly how many flight we have since then. If I have to guess I would say it's around 50-70 flights.

View attachment 16784View attachment 16785View attachment 16786

Thanks for posting the pictures. Hard to tell for sure without a macro shot, but the remnants of the failed joint and the remaining intact joints suggest that a 'cold' solder joint may be to blame. Others have commented here and elsewhere that it is tricky soldering these wires because of the risk of adding too much heat for too long and disrupting the integrity of the copper solder pads. The best approach seems to be using a sufficiently high watt soldering iron with enough thermal mass to quickly raise the temperature of both the end of the multistrand wire and the solder pad enough for a good bond, while avoiding overheating the pad or the wire (causing wicking beyond the desired stripped end. The ideal appearance of a joint immediately after cooling is one with a bright silver relatively smooth surface that clearly integrates both the solder pad and the wire. If the joint appears mottled, dull, and irregular, there may be a problem with both electrical and mechanical integrity. May want to inspect all the previously re-worked solder joints and re-solder those that don't look ~perfect.

Steve

 

[ProPilotWannaBe]

Thanks for posting the pictures. Hard to tell for sure without a macro shot, but the remnants of the failed joint and the remaining intact joints suggest that a 'cold' solder joint may be to blame. Others have commented here and elsewhere that it is tricky soldering these wires because of the risk of adding too much heat for too long and disrupting the integrity of the copper solder pads. The best approach seems to be using a sufficiently high watt soldering iron with enough thermal mass to quickly raise the temperature of both the end of the multistrand wire and the solder pad enough for a good bond, while avoiding overheating the pad or the wire (causing wicking beyond the desired stripped end. The ideal appearance of a joint immediately after cooling is one with a bright silver relatively smooth surface that clearly integrates both the solder pad and the wire. If the joint appears mottled, dull, and irregular, there may be a problem with both electrical and mechanical integrity. May want to inspect all the previously re-worked solder joints and re-solder those that don't look ~perfect.

+1... to me that looks like a cold solder joint that came undone. As Steve said, after the soldering cools, it should looking like a solid mound... not that all of mine look that way, but I'm still learning how to perfect my art of soldering as well.

junanata, how long had you been flying the S800 since that ESC was soldered? Just to give us a timeframe for wear and tear purposes...

 

[junanata]

Thanks for posting the pictures. Hard to tell for sure without a macro shot, but the remnants of the failed joint and the remaining intact joints suggest that a 'cold' solder joint may be to blame. Others have commented here and elsewhere that it is tricky soldering these wires because of the risk of adding too much heat for too long and disrupting the integrity of the copper solder pads. The best approach seems to be using a sufficiently high watt soldering iron with enough thermal mass to quickly raise the temperature of both the end of the multistrand wire and the solder pad enough for a good bond, while avoiding overheating the pad or the wire (causing wicking beyond the desired stripped end. The ideal appearance of a joint immediately after cooling is one with a bright silver relatively smooth surface that clearly integrates both the solder pad and the wire. If the joint appears mottled, dull, and irregular, there may be a problem with both electrical and mechanical integrity.

Steve, thanks so much for the tips.

May want to inspect all the previously re-worked solder joints and re-solder those that don't look ~perfect.

Steve

Yup, that's what I am going to do my friend.

 

[junanata]

+1... to me that looks like a cold solder joint that came undone. As Steve said, after the soldering cools, it should looking like a solid mound... not that all of mine look that way, but I'm still learning how to perfect my art of soldering as well.

junanata, how long had you been flying the S800 since that ESC was soldered? Just to give us a timeframe for wear and tear purposes...

Since September of last year. We fly about once a week except in the winter; November to March.

 

[ProPilotWannaBe]

Since September of last year. We fly about once a week except in the winter; November to March.

That many flights on that solder joint? Wow! That would be cause for serious concern for anybody that has resoldered their ESCs. Thx for the warning.

 

[junanata]

That many flights on that solder joint? Wow! That would be cause for serious concern for anybody that has resoldered their ESCs. Thx for the warning.

Pro, it could also have been a bad solder on my part.