Tuesday, June 3, 2014

The X-525 quad does a splash down crash at the beach

It was another night flying day at Pattaya beach with “Toy man Paul” and Big Paul his friend with the phantom 2 and of course myself Scotty. The evening was about to end almost without incident when Big Paul and his friend at about 12:00am packed up and went home. It was just me and Toy man Paul left to do one last flight with the X-525 Quadcopter that had already flown two batteries this night and we had one more fully charged battery left for it. So Paul took it up and flew for the first  few minutes of the last flight and then passed me the controls to finish off the last of the three batteries we have for it. It was flying very stable with no problems with the audio voltage telemetry return now fully calibrated with the naza so you didn't have to worry about the battery going dead without giving you plenty of warning. I started getting cocky and confident at this point and flew it out over the side walk and at very high altitude of about 150 feet I took it a ways out over the water when suddenly all the lights on the aircraft flickered for a moment. When I saw that I knew there must be something major going wrong. I immediately pulled the stick back to try to at least get the X-525 over sand instead of water but it was already too late the lights on the aircraft stopped blinking and the aircraft appeared to just disappear like magic if just vanished with nothing but darkness to see. At the high altitude it was at I couldn't see anything at all up there. I continued to pull the stick back with lots of down in hopes it was just the lights that had failed. But about 3 seconds later the X-525 came back into view when it got to the altitude of the big lights at the beach that light up the ground, but now it was falling like a rock at 32 feet per second per second with no lights and no props spinning just tumbling down to make a big splash into the ocean about 80 feet off shore. I took some quick land mark readings in hopes we could at least recover what we could of the aircraft. I then made a big line in the sand from where I was sitting on the side walk to the waters edge. I pulled out all the items in my pockets including my phone and went for a swim to see how deep it was at the approximate point of impact. We picked the worst night for this to happen as it was a spring tide that we were only about 80 minutes past one of the highest tides of the year. When I got out about as far as I thought the aircraft was I found that at that point it was about 9 feet deep as I put my hands up I could feel the tips of my fingers go under water about 1 foot more before I could feel any sand at my feet. I boobed up and down a few times in hopes that I would feel the aircraft with my feet if I got close enough but luck was not in our favor this night. I gave up hope at that point that the aircraft was going to be recovered at this point in time with tide levels now at about 3.5 Meters. When I got back to shore I gave Paul the bad news that he must have already known as I was coming back empty handed and he was also a witness of the incident. He asked “what do you think is it a goner”. I said “no way!” I was sure we would recover the aircraft when the tide goes out since tomorrow was also going to be a near record low tide at 2:03pm the next day of about 1 meter. At that level the aircraft will be almost completely visible and maybe even poking out of the water at that depth. Paul was ready to give up and head home and he asked “so what's the plan, come back tomorrow then?” I said “no way I'm camping here until the tide goes out”. All I really need is the tide to go down about 3 more feet so I can still stand on the bottom to setup a search pattern. Paul laughed “camp here OK good luck”, he said “I'll take the second shift tomorrow in the event you fail and bring my dive mask to find it in the light”. I said “that's a very good idea”. So he headed home and so it was just me and my present side kick Ann to keep me company and boost my spirits. She's been into playing the musical instruments I have programed into my android phone so we continued to play with it together and worked on some of our new songs with a program called Looper. With that we managed to make some of the worst sounding things in history from grunts to farts and other strange noises we could figure out how to make and laughed as we mixed then together to make some strange sounds that maybe some might want to consider as music. Who knows maybe we created the next hit single on this night. Anyway it was a good way to pass the time and it seemed like no time at all had passed when it was almost 2:00am when I could see the waters edge had gone down about 2 meter from the reference marks I had made in the sand to track tide changes. At that point I was ready to give it another attempt to see if I might reach the bottom near where we think the aircraft was. I had also added a few other lines in the sand that were added as worst case error lines to use as ends of the search pattern as we went out that I had planed before I started my search. Paul had also got some information earlier from another group that had been siting on the beach not far from were the aircraft went down that said from were they were siting it was strait out. So I had also added lines in the sand from there vantage point to the water to add a second reference that we could triangulate to get an approximate distance out to sea that it resided. So it was time to act after all this planing I jumped into the very nice cool water and put my plan into action. The water was perfect not cold at all in fact I think I'll start swimming more often in the evening to cool off in this very hot weather we are now having and also find it even more fun when I get Ann to join me witch she already had done in this night in an early second attempt to find the aircraft that ended up being more of a pleasure swim than a search attempt with more opportunities to grope on Ann's perfect 20 year old body instead of a search, as I found it was too deep on that try that I didn't even count it as a search. But now this time things were looking up. I was near were I thought it was and I was still able to keep my face above water. I had already did most of the planed search and I was working on new ways to move my feet in a wide circular pattern to widen my swath without the possibility of missing anything. I was hitting a few other object most just rocks but lucky I didn't run into any broken glass yet. Finally I hit something just barley in reach of my foot as I just nicked something tall with my toe that was out about 30 degrees down angle and out about another 3 feet from were I was now standing. I started slowly moving in the direction of this only brief touch of something to see if I could again feel with my foot with more detail if I was to hit it again. Sure enough I got a few more taps of something that didn't feel like a rock or any other debris that I had felt in the past. When I was only inches away I could now feel the legs of the aircraft at my feet wow I had found it almost for sure! I grabbed it with my toes like the monkey that I am and pulled the aircraft to my hand and then to the surface of the water and was able to get the first glimpse of the recovered aircraft. It was still too deep at this point to analyze it with any detail so I had to make head way back to shore that was now about 60 feet away. As I made progress in the shallower water I was able to lifted the aircraft above my head and shouted to Ann that was now at the beach edge guarding the stuff and watching me as I did the search. She jumped up and down with glee for me for my now heroes success in that cute little energetic body she has. She would have been swimming with me on this search but we had some Thai boys hanging around scouting our stuff so she had to stay behind on this swim and keep an eye on our remaining equipment and my phone and wallet that I had to leave on shore. So in my opinion she is just as much a hero as me finding it, since we couldn't have done the search without her present. When I got to shore I did a bit more analysis of the aircraft condition to note that the battery was no longer installed in the Velcro holder. I was quite certain it must have released on impact with the water as when I watched the splash down there was only one splash not two when I saw it hit the water on it's crash. If I could have seen that the battery was not on the aircraft when I first found it I would have continued the search near it but now it would be almost impossible to find an object that small out there at the present depth. Maybe we will get lucky and find that part tomorrow. Also there was two broken props on the X-525 on one side of the aircraft that must have taken a hard hit on impact. But props are cheap and we have plenty of those in stock. I also made a phone call to Paul telling him we found the aircraft and a brief report of it's condition almost as soon as I got to shore with it. I recorded the time of the call to him at 1:53am. So after that I packed up the gear and headed back home to see what else we might be able to recover on this aircraft that has now spent around 3 hours in sea water at about a 9 foot depth. I've never had much luck with electronics in sea water in most cases but I have had a few parts that I have worked. I have become more of an expert at electronic sea recoveries with all the flying we do at the waters edge we have had many things go down there. So my plan was to go after the most expensive parts in hope to recover the Naza flight controller and the frsky receiver first. My plan was to first dissemble and soak them in reverse osmosis (almost distilled) water for a few minutes and a little more dipping and drying and dipping in the water in hopes to remove most of the minerals between contacts. After that let it dry for a bit then spray it with WD40 then sponge it dry of that with a paper towel and put under a fan to try to continue to dry it out. As soon as the sun comes out I plan to let it sit in the sun and bake for a at least a day to dry it all out. The other parts of the aircraft I did much the same as above with the motors and the esc. I am confident we will recover the motors but less likely we will be able to recover the esc but I haven't given up hope yet. They now are all siting in the the very hot sun we now have baking dry as we speak (or write). I will later update this article with what we got to work after the process we documented above.   Also there is data that is captured in the Taranis radio that I have setup to record all the telemetry from the aircraft and all stick movements detected on the radio with time stamps that we can look at later to see what we can find.  I am quite certain that the problem that caused the crash is due to an intermittent contact at the point of power from the battery from the balance connector that is used only to power the aircraft lights, radio and the naza flight controller.  The power to the ESC on this aircraft come from the main battery plug that wouldn't have effect the lights on the aircraft if it had failed as we saw before the crash there were no lights.  There is a small posibility that the battery completly disloged from the aircraft as we didn't see it still hooked in after recovery but it is very unlikely that case as we only saw a single splash at crash.  In the future I don't think I will depend on the balance plug power for flight critical parts in future designs.  I've also added another step to the above by using a contact cleaner called Kloud that I had already in the house.  I was told by Big Paul that WD40 leaves a residue that may not be good on electronics so the Kloud acts like a degreaser that I hope fixes what might have been a bad idea with the WD40 I used before.

Update Jun 3, 2014  14:46pm
I made another attempt at recovering the battery that has not yet been found at the beach today at 2:00pm that was supposed to be low tide on this day of about 1 Meter.  When I got to the beach I could see the lines in the sand I had made the night before as there seems to have been alot of trafic of something that seems to have wiped both my lines out.  I made new lines that are not as acurate as my first and with these I continued the search in the water.   The water at the estimated point of the estimated aircraft crash was at about .5 meter water level.   The water was very dirty with limited view of not more than 4 inches at best.  So there was no chance of finding it visually.  I continued using my feet to search but later found nothing but broken glass and then some kind of strange sea creature dashed out from under my feet that freaked me out to a point to abandoning my search efforts.  I covered about 100 sq meters at that point with nothing to show for it.  I also offered Loe and the gang of bums at the beach a 100 baht reward if they were to find it but they didn't think that was enough to even give it a try.  What does the labor of a beach bum run these days?  That would have got them 3 Sato's if they found it!

Update jun 3, 2014 16:25:
I powered up the Fr-sky D8R-XP receiver and did a full lab test everything is ok after the clean up above.  So things are looking up so far.  I continue to dry the other parts before power up tests on them.

Update jun 23, 2014 8:19am
we got all the parts of the X-525 working again after a loan of the star tool needed to open up the gps module that we got from Big Pual.   That was the last part we couldn't get to work without opening it.  After we opened the gps module and soaked it in distilled water for 10 minutes and dried it in the sun for 2 days we got the complete set working again.  We now plan to give it a flight test tonight to see how it really goes.   I also looked at the flight logs from the Taranis on the night of the crash and noted the failure couldn't have been the power connector for the lights that failed since there is redundant 5vdc power to the receiver and flight controller that comes from each of the four esc's to each prop.  The last telemetry signal received from the aircraft showed that we had 11.8vdc at A2 and 5.04vdc at A1 then a sudden rssi signal loss from 63 to 0 from the reciever at 23:26:11.409 on Jun 2, 2014 when I was in hover mode with all sticks almost at perfect center positions with mode switch still set to gps.  So all I can think it could be is that we had a complete battery failure from both power path of the lipo at the same time since loss of power from ether power path would not have looked like this.  If the balance plug power failed as we had originally thought, then the lights would have gone out as we did see but the aircraft would have been put into auto land mode as the flight controller would have sensed battery power low so the aircraft would have come down with controlled decient and the telemetry would have sensed the A2 power voltage drop to zero.  I plan to simulate the broken balance plug to be sure I'm correct  to see if we need to make any changes in wiring for future flights of this aircraft.

The X-525 after disasembled and drying in the sun:

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