Costly and frustrating start to my foray into hexacopters.... a heap of parts for a 3DR Hexacopter arrived last Friday, including APM 2.5, 5000mah 4s lipo, sonar sensor, 3DR telemetry link, uBlox GPS and the kit 850Kv motors and 10" props. Asembled and working for Sat morning, with a couple of test flights in the garden Sat evening. All good at this stage, but a couple of the prop nuts span off causing some crashes into the hedges. No damage, but did need a metal detector to find the missing bits.
As of Sunday, I switched all the prop nuts for nylocks and went for some higher altitude tests, tested RTL and loiter functions.
Stabilise test:
https://www.youtube.com/watch?v=f-9JV8qvOsQ&feature=g-upl
RTL test:
https://www.youtube.com/watch?v=mtlYYcI2dn4&feature=g-upl
Fast climb test:
https://i3.ytimg.com/vi/njhNUfK-BZE/mqdefault.jpg
Today the weather improved, and managed to nip out to a local abandoned airfield to test the telemetry link and the auto waypoint navigation. All went well for about 30 sec, taking off smoothly to hover at 20m, then ascending to 50m for the next waypoint...... then disaster struck as I watched a prop flutter off into the distance, and the copter go into a terminal tumbling dive, crashing at high speed into a shallow bog!
Suffice to say, it did not fair well - two motors sheared off the alu struts, four props shattered and the electronics stack shredded along with its protective foam cover.... not a pretty site. Plus it was sat in about 5 inches of muddy water, covered in grass. Dragged it out, removed the lipo and then trudged back to the car with my expensive armful of wreckage :(
So - the lesson - make sure your prop nuts are tight, very tight, and loctite'd and perhaps even lock-nutted! Fortunately it didn't hit anyone on the way down, but there were some spectators nearby who almost cheered at the splash it made and then watched fascinated as I fished bitsout the bog.
Now to order some more bits.... hopefully mk2 will last longer than 4 days!
Comments
@R_Lefebvre - thanks, wife was holding the camera so hadn't noticed he'd got so close.
@GeoBlu - not proud, just keeping the tone lighthearted for a forum - very relieved no-one got hurt
@Randy - thanks for the tip, will take a look
Sorry to hear about your crash. Happens to everyone.
Re the props coming off...the company I work with in Japan, EnRoute.co.jp has both normal and reverse prop nuts. So you put them on the way that makes them tighten as they spin rather than loosen. I don't know of anyone else that sells this kind of thing but I hope it catches on!
Typical knuckleheads! These are the guys who make life (multirotor world) difficult for us who play by the "rules" and use our common sense when handling these aircraft. In a period of less than 48 hrs, he received, built, and attempted flights, almost creating complete havoc. It seems by the post,that he is almost proud of his performance. Like said before, "this is not a toy". Take your time, seek out help from those that know, isolate yourself (flying site), and start with basics instead of trying to much to soon. I use a written "checklist" from pre-flight thru post flight. "measure twice, cut once", meaning, "think it thru man!"
Damian, just a tip, I won't let my daughter who is 3 outside to watch me fly unless my wife is there to watch her, generally. You just can't control the little ones while you're flying. Sometimes I'll let her out when it's just me, but on the deck and she's behind a railing.
@Alexsey: for 880kv motors dont use ANY prop ring adapter/spacer, they will prevent you from putting as much pressure as you should!
try it and you will see.
my experience with quads is that you need to be really careful. You can't have spectators, children or what within 10m of the thing. Please heed this advice.
The quad didn't appear to be calibrated properly, which you could easily catch in a session where you have it roped down. The gains are too high, causing the whining noises of the ESC's going all over the place.
Sorry about the loss, been there, done that. Please be careful where you put your family! :)
evening all, appreciate the concern for the child - my son as it happens, who came much closer than he was meant to - fortunately learnt that lesson, hence the next flight was at an airfield - although didn't account for dog-walkers coming over to take a look mid-flight. Will prob. move to flying club next, as at least people know to stay back.
As to the prop nuts - should really have gone straight to the loctite on the threads, hindsight, etc. and will double-check the collets are fitting properly - first time I've used them and wasn't confident I had it quite right, but was sure the nylocks would have solved it.
Going through the parts this evening, it seems the APM survived - or at least as much of it as I can verify at this point, as did the GPS module, 3dr radio, receiver, possibly four of the motors and two props. Lipo also seems fine, but hard to tell if there's been any internal damage. All the ESCs were knackered.
@R_Lefebvre, @jasonshort - thanks for the advice on the rate terms - I wasn't sure if that wobble was due to the wind or was a tuning problem, but it was on my list to check, once I'd worked out which rate term to play with. Will try Rate P first once machine is rebuilt.
@monroe - good shout, will def be checking balance and running some speed tests before trusting any of these motors/props...
now off to watch crash videos and see what else I should know before building/flying mk2
Thanks Alexsey. I went to the 3dr store but couldn't tell for sure.
Okay i checked. I've used biggest adaptor ring from the kit of two. So it just cannot be adapter ring. I also tried to tighten screw as much as i go, but it is still can be removed with the prop with hand...On the shaft it looks similar to other props those sit really tight...
Thank you guys, for your comments, i'll check this out.
880kv motors have 3 holes.
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