My 4-Day Experience w/ Ardu 3DR Kit - A Newbs Review - Discussions

I finally bit the bullet and ordered the 3DR kit. #excited

I should preface all of this with the fact that I'm not a hardware guy, software guy, r/c guy, hax0r extraordinaire, FAA commander, or anything that would make me particularly qualified -- I ordered the kit, followed the instructions, and happen to have an experienced quad flyer friend to bounce questions off of.

To start, my experience with the ordering system was lacking -- multiple kits "in-stock" but nothing could be added to my cart because one of the items in the kit was not in-stock. I could see this being an issue if it were a major component, but it was the velcro battery strap. So if you cannot delay shipment until said part arrives, and you won't let me add the kit to my cart, then you really don't have any in-stock.

Kit arrives and I spend the next two and a half days or so building the 3DR per the instructions in the wiki. It wasn't really all that difficult, just a lot of tedious work - checking, double checking, oops and fixing, etc. Issues that I had included the instructions not matching the hardware I was sent. Cables weren't the same colors, parts were off, etc.

After the main frame assembly was complete there was a very noticeable "arch" on two of the arms. If oriented in "plus" mode instead of "x" mode you would notice that the left and right arms were both angled backwards by several degrees, while the fore and aft arms formed a straight line in relation to each other. The left/right arms had to be measured and drilled out a bit to make them straight. Poor QC imho.

It was also interesting to see that 3DR was shipping bullet connectors as from my research they are notoriously sketchy. Not that it's a show stopper, but "sketchy" is not a word I want to use for any components going into a fairly expensive flying device. Replaced all the bullets with dean connectors which seem to be pretty stable. (also per the rec of my quad flyer friend)

The configuration of everything seemed to be pretty straight forward with no major or noticeable glitches. Once the beast was built it was time to see if it would fly!

Flying started slowly until I could get a feel for how this thing works. I can say that after a few minor adjustments it was picture perfect! Hovered well, responded well, and seemed to generally be a rock solid performer. I was definitely stoked to fly more. I drained one battery in testing.

Day 4: I head to the quad flyer buddy of mine's house and we head out to a HUGE field to play around and for me to learn a bit more. Drained another battery and everything seemed grand - and then...

After putting in the second battery (3rd battery that's ever been used) I start noticing a little glitch -- the controls don't seem to respond, but only for a second. The quad is hovering nicely, bank right, nothing - being a newb I'm not sure what's going on as everything else has been spotless. Bank right again and we're back. This happened a couple times in various spots, but nothing major.

We then do a vertical assent, which I've done a couple previously, but this time was different, much different. I "gas" it to probably 75% throttle and the quad shoots straight up, fast, I let off the throttle and nothing happens. The quad continues to climb and no controls will work! There was a 2-3mph cross wind and the quad climbed and was blown sideways FOR MILES. A more or less fresh 2650mah nano-tech battery carried this bitch further than I could see it until it was nothing more than a black dot across the grey sky. Nothing worked, nothing stopped it. Gone.

I have no means of locating the craft let alone troubleshooting wth happened - could it have been a bad board? bad radio? software malfunction? short? I'm not trying to lay blame on 3DR or anything, but there are a lot of assumptions made in the assembly instructions, stuff that's just plain not there, and if I didn't have an experienced pal assisting there would have been a lot of unanswered questions. Heh, at this point there still are.

So my take away from this is - WTF. I completely lost the quad I just paid 600$ for, spent 2 days building, have flown twice - barely, and have no clue as to why it decided to full throttle to the stratosphere. There appeared to be zero issues with any of the equipment, all fresh batteries, and much to the bewilderment of my experienced friend who commented that he's never seen that happen before.

So the two flights I got out of this device were awesome and I was told it was handling very well and looked spot on. Irrelevant at this point I suppose as I don't even have a handful of busted parts to scavenge from. I lost the entire craft, a brand new battery, and radio gear.

#nothappy

Seriously though, getting back to the original poster minus all the other opinions, the facts seem pretty clear. The accident was caused by a failure to set proper "failsafe" settings into the radio receiver, and then further, lack of testing with props off to ensure those settings worked with the APM. In other words, follow the failsafe setup instructions from the radio's manual, then test that under live conditions with the props off by removing the transmitter's antennae and doing a range check and/or bring the aircraft up to throttle and then turning the radio off. Every good radio I have ever owned said to do those exact steps (JR, Futaba, Airtronics, and of course Spectrum).

Further mitigation (again, not a fix for the above steps which are REQUIRED), is to use the new fencing code variants and ensure you set them. The biggest concern here is that you the pilot must be in control at all times, and further, have been trained and practice and know what to do in the event of major radio glitch or system failure before you ever bolt on the props and try to fly. There simply is no excuse to blame this on the APM. It's meant for pilot assistance to help with tedious or difficult tasks such as loiter, altitude hold, moving to set waypoints, all with the pilot in constant radio contact and control. In no way was the APM or code ever designed to "save the aircraft" or "prevent a crash". If you think that's what it does or should do, then you need to be looking at a much more expensive redundant system and sensor package that includes some sort of obstacle and collision avoidance-something we haven't even thought about on the current APMs. Without collision avoidance, any of the measures described as safety features such as RTL, RTB, Circle at altitude (loiter), have the potential to actually cause a crash, not prevent it with fixed objects such as buildings, light poles and power lines and maybe even people! If you are not in control, then we must assume the worst.

I'll add that further, this is why the brand name radios cost more. It doesn't mean they are fool proof, just that they probably are a better radio since they are often certified by the FCC and also tested by groups such as the AMA. Flying a $600 aircraft with a less than $200 radio system or non-name brand might be expected to exhibit problems like this with untested failsafes, lack of radio interference rejection and a whole host of other issues. Cost is not the most important consideration, but you really do get more for a name brand product.

I cannot stress enough that the builder is responsible for the safe operation of the aircraft. You must test and know what it will do before you put it in the air and put both yourself and others at risk from an out of control machine.

No doubt this sucks to have crashed and LOST the aircraft, but at the same time, for other new flyers, this is important info to take away.

Replies

Ron Sindric September 13, 2015 at 2:52am

Another comment. One of the contributors to this thread talked of how DIY-ing with RPVS ( UAVS, UGVS, UWVS, and UUWVS ) is not a simple plug and play. He was right. I hope you forge ahead and keep QUADDING. When you Gremlin-proof your 3DR QUAD, it'll be time to move on to something else like the LYNX VTail http://www.lynxmotion.com/c-167-vtail-500.aspx. I am a small bit curious what it would take to QUAD through the atmosphere of Mars. Here is a quote from John Chatterton Medic-4th Battallion 31st Infantry. I gleaned it out of a book called SHADOW DIVERS http://www.barnesandnoble.com/w/shadow-divers-robert-kurson/1102097... .

Chatterton.doc

Lynxmotion - VTail 500

VTail 500
Ron Sindric September 13, 2015 at 12:19am

Right now I have cheap toy QUADS. Next week I'll be ordering my 3DR QUAD KIT so all these posts are of interest to me. Even to a reeeeeal green guy like me, I would say that at the VERY FIRST SIGN OF EVEN THE SMALLEST IRREGULARITY the best thing is to ground the bird till you can do a fix to shake off those pesky air-gremlins. Small steps, lots of testing with very short flights, comprehensive log book notes añd a sprinkling of Holy Water might have lowered your chances of a "Bye-Bye-Quaddie". Hope you find the pieces. Get it back in the air and post again. Good Luck !
Zen May 17, 2012 at 8:12am

I know this thread has finally died down, but I wanted to post a relevant thread for anyone who may find this one in the future. It would appear as though the Turnigy 9x was NOT to blame and that the fly-away was directly caused by the APM.

http://diydrones.com/forum/topics/help-with-new-first-tx-rx-purchas...
Andreas May 7, 2012 at 9:08am

As far as I know the only way to get failsafe to work with the Turnigy 9x is to use the FrSky module and receiver (or similar?).

I put a plane into the bay because the 9x lost connection. Now I'm setup with the FrSky and the plane will RTL on signal loss (just programmed the receiver output to set RTL mode and 50% throttle on signal loss). Also the radio seems to be less glitchy with FrSky. Worth the investment.

With the Aurdocopter it's a bit more tricky. I can't always trust that RTL would actually do the right thing. Still in the midst of tuning things that loiter would actually be reliable instead of just flying off to a unknown destination. Maybe 25%-30% throttle would be the best setting for now. -> Fall down but not as fast as gravity would dictate.. but it would start to mow the lawn after impact...
Vernon Barry May 2, 2012 at 10:16am

Seriously though, getting back to the original poster minus all the other opinions, the facts seem pretty clear. The accident was caused by a failure to set proper "failsafe" settings into the radio receiver, and then further, lack of testing with props off to ensure those settings worked with the APM. In other words, follow the failsafe setup instructions from the radio's manual, then test that under live conditions with the props off by removing the transmitter's antennae and doing a range check and/or bring the aircraft up to throttle and then turning the radio off. Every good radio I have ever owned said to do those exact steps (JR, Futaba, Airtronics, and of course Spectrum).

Further mitigation (again, not a fix for the above steps which are REQUIRED), is to use the new fencing code variants and ensure you set them. The biggest concern here is that you the pilot must be in control at all times, and further, have been trained and practice and know what to do in the event of major radio glitch or system failure before you ever bolt on the props and try to fly. There simply is no excuse to blame this on the APM. It's meant for pilot assistance to help with tedious or difficult tasks such as loiter, altitude hold, moving to set waypoints, all with the pilot in constant radio contact and control. In no way was the APM or code ever designed to "save the aircraft" or "prevent a crash". If you think that's what it does or should do, then you need to be looking at a much more expensive redundant system and sensor package that includes some sort of obstacle and collision avoidance-something we haven't even thought about on the current APMs. Without collision avoidance, any of the measures described as safety features such as RTL, RTB, Circle at altitude (loiter), have the potential to actually cause a crash, not prevent it with fixed objects such as buildings, light poles and power lines and maybe even people! If you are not in control, then we must assume the worst.

I'll add that further, this is why the brand name radios cost more. It doesn't mean they are fool proof, just that they probably are a better radio since they are often certified by the FCC and also tested by groups such as the AMA. Flying a $600 aircraft with a less than $200 radio system or non-name brand might be expected to exhibit problems like this with untested failsafes, lack of radio interference rejection and a whole host of other issues. Cost is not the most important consideration, but you really do get more for a name brand product.

I cannot stress enough that the builder is responsible for the safe operation of the aircraft. You must test and know what it will do before you put it in the air and put both yourself and others at risk from an out of control machine.

No doubt this sucks to have crashed and LOST the aircraft, but at the same time, for other new flyers, this is important info to take away.
Developer

Andreas M. Antonopoulos April 30, 2012 at 9:34pm

I'm thinking of adding a warning in the wiki, on the page about connecting the RX that says something about TX/RX failsafe settings and ensuring they are correctly set.

I also think there should be a big red warning in the "First Flight" section that says: until you are confident in your piloting skills and have tested the failsafe systems, do not fly above tree level/building level (as winds and distance/visibility can make the copter hard to control) and avoid high speeds (ditto).

I say this not to chastise the OP in *any* way. I am currently rebuilding my copter for the 4th time, after 3 very bad crashes all caused by runaway altitude issues because of pilot error (aka Me-the-dufus-at-the-controls). So I have been humbled by making this mistake a few times, which prompted me to try and improve the failsafe systems for ArduCopter.

I just see it as a common failure mode. We need to address this issue in two ways, IMHO: document and automate it away. Document the issues that lead to this outcome and try and get geofencing and other improvements into production.
Vernon Barry April 30, 2012 at 5:38pm

Also need to add a comment about the bullet connectors since you clearly didn't get the whole story. The reason some have issues is they are a hard connector to solder properly and worse if you have limited soldering experience and cheap soldering tools. Bullet connectors themselves are not at fault. The issue is there shear mass of the metal that needs heated means you need a big iron (40watt or more), good clean tips, and a solid way to hold the connector and the wire (helper hands). Further, the cup shape in the end when you stick the wire in is very hard to inspect afterwords to ensure you didn't get a cold joint and there is enough solder flowed into the wire and the cup. Because of this, many people have had bad solder joints and not known it. Add to that the heatshrink on top which further could mask a loose wire. That's why people have problems, it's not a bad connector, it's shoddy soldering.

I totally get it that you're pissed but at the same time, this is a DIY project. ANY radio control system (car, boat, heli, plane) has the exact same problems. The problem again here is that they sell you the aircraft kit and you add your own radio. They cannot exhaustively cover every radio out there and it's up to the radio manufacturer to give you that info and for you to follow it.
Vernon Barry April 30, 2012 at 5:29pm

So my take away from this is - WTF.

Ok, it's clear here you have some serious expectations that no autopilot can deal with.

Your primary failure sounds like a radio range signal was lost. When that happened, either the receiver you used or the failsafe settings in the radio receiver were completely wrong. The problem here is, if your receiver sends valid PWM/PPM coding to the APM, you might as well heve been telling it to do it with the sticks. Next, if you were in stabilize mode, the ONLY thing the APM is doing is trying to keep it level. It will not keep it from crashing because that is a manual mode meaning YOU are flying the machine. Had this been a regular heli with NO APM, the exact same thing would have happened based on your setup.

Bottom line, if you lost radio, you couldn't even switch modes unless you had remote telemetry setup and even then you wouldn't have the time.

Many get into this hobby and don't even follow BASIC radio control setup inlcuding failsafes. The instructions cannot account for this with all the different RC gear out there. That's why your RC gear has it's own manual. The settings you failed to do are in the instructions for your radio, not on the wiki.

Even professional multi thousand dollar auto pilots cannot deal with a cheap radio link issue, especially if they are in a stabilise mode. To both the autopilot and the machine, your radio was the problem. A multi thousand dollar APM aslo comes with an expensive radio with link info and properly setup failsafes.

We all feel badly for the loss and this is a hard first lesson. The bottom line is learn from this, understand the rules of radio control before you go adding an autopilot. Test your system on the ground with no props and turn off the radio. Perform radio range checks (again in the radio manual).
Crispin April 30, 2012 at 5:16pm

Bummer to hear but, go look for it. I've found mine after what seemed hopeless fly-away, a friend 3 times.
Zen April 30, 2012 at 2:33pm

So to be clear - I bought the kit from DIY, as-is, and what came with it is what I used.

I specifically bought this kit BECAUSE of all the safety/auto shit that's included, but didn't enable or investigate for any maiden flights.

Now that I know what's possible I would say that it's a requirement to geo fence during initial flight testing. That way if failure at least it'll be contained. I would also state that after initial testing and "burn-in" is done and everything appears to be safe, that telemetry is the next requirement. That way if fail at least you have an idea as to where to look for your shit.

I don't think anyone except the guy who was with me knows how far this thing went. It was literally almost completely out of sight, both in height and distance. Without last know coordinates we wouldn't even know where to begin looking. Someone also mentioned a liability issue, and you're spot on... It's kind of scary thinking that UAV's can just fly away on their own and drop from the sky.

RTL on signal loss, geo fencing, telemetry, gps transponders, etc all sound cool but seem 100% necessary to me. How does one know if their aircraft is 100% reliable? How much testing and air time need to be done before you're comfy knowing all is well? Sounds like you never can be 100% certain, which to me sounds like safety should be 100% required.

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