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DJI - ok - maybe not as good as I previously thought.

#1
I've lost 2 DJI copters now.
First one was the quad (F450).
The GPS hold didn't hold so well and it drifted and hit a branch. No big deal - some very basic patch work. A few flights later it looks like either it lost a prop or an arm cracked. I marked that up to my fault - I was too cocky playing chicken with the branched ;-) and obviously missed something that failed a few flights later.

Next I picked up the 550 (hex). Had a hell of a time getting it configured (odd since the first one worked out of the gate) - but in the end I got the GPS and all that stuff working beautifully.

Today I was doing about the 20th flight or so on it, showing off the GPS return home/land feature. So I took it a good distance out and hit a switch that forced it into fail safe mode. It started acting kind loopy - like a toilet bowl effect - and was getting further and further away. Quickly took control again to try and nurse it home. Couldn't do it - it seemed completely out of control as it was swirling around and getting further and further away (and higher by the looks of it). Finally I lost sight of it. Hell - it must have been miles away. I switched the radio off - hoping that the GPS return home (which has worked perfectly many times before this) would do it's job - nope. It's erratic flight makes me think that it lost a prop or something.

So somewhere - miles away from here - there's a $700 pile of equipment somewhere. Hopefully not on the hood of someone's car... but man - it was WAY the hell out there.

Definitely won't be getting another DJI machine.
 
#2
Did you use the same motors on both? Could motor(s) have been damaged by hitting the branches and finally shows up? Sounds like something was so wrong the NAZA could not get control but was trying hard to. Have seen weird behavior when things were not right loose like props, things turned around backwards. In other words, when the motors are not working correct the NAZA simple cannot maintain control. Suspect it was not the brain but the mechanical parts causing the problem. Brain can only control when things are as it expects them to be.
 
#3
Did you use the same motors on both? Could motor(s) have been damaged by hitting the branches and finally shows up? Sounds like something was so wrong the NAZA could not get control but was trying hard to. Have seen weird behavior when things were not right loose like props, things turned around backwards. In other words, when the motors are not working correct the NAZA simple cannot maintain control. Suspect it was not the brain but the mechanical parts causing the problem. Brain can only control when things are as it expects them to be.
Nope - I picked up a completely new kit - new arms, motors, ESC, props. Even a new stabilizer "brain".

I've seen bizarre behavior too with props spinning the wrong way but the first minute or so of the flight was normal - and in fact it had about a dozen flights under it's belt this past week.

One thing that bugged me - the counter rotating props did not have counter rotating spinners on them.
 
#4
After several loose props, I now double nut them. Never knew if the loose prop was the cause of the crash of the result. Seems my crashing has dropped a bunch since double nuts.

Unless we get a bunch of similar reports pointing to a bad batch of brains, suspect some weird thing happened to you. Hope you can find it.

Can feel your pain in the pocket book and confidence to get in the air again. Makes me want to keep it close.
 
#5
After several loose props, I now double nut them. Never knew if the loose prop was the cause of the crash of the result. Seems my crashing has dropped a bunch since double nuts.

Unless we get a bunch of similar reports pointing to a bad batch of brains, suspect some weird thing happened to you. Hope you can find it.

Can feel your pain in the pocket book and confidence to get in the air again. Makes me want to keep it close.
Agreed - I think it was the brains trying to compensate for something wonky going on but simply couldn't.
Anyhow - "double nut(ting)"... I assume you're referring to a build technique and not a favorite Fri night past time (HAHA! sorry - couldn't resist).

How do you double nut a prop/spinner? Pics? I can't seem to visualize that. Hey - maybe that's an flitetest "article" idea for ya.
 

colorex

Rotor Riot!
Mentor
#6
How do you double nut a prop/spinner? Pics? I can't seem to visualize that.
Yeah, it may seem illogical to double-nut a spinner. But it's possible, at least with the type that came with my Park450 motor. Just get the right size nut, screw it on tight, then put on the spinner.
 
#9
So much for the theory of paying premium $ for premium product.
Careful guys about jumping to a conclusion, it will probably be wrong. With one down does not make it a bad product, more likely a simple mechanical problem that caused a unstable therefore and uncontrollable aircraft. As noted above, the brain has to have four good controllable motors for it to work. One motor problem will cause the whole thing to be uncontrollable by man or machine. Know this for a fact from personnel experience.
 

Tritium

Amateur Extra Class K5TWM
#10
Three issues I have with DJI as a non-owner of their controllers (I do own their 550 motors and props).
1. Captive House Phone Home Software,
2. Somewhat ridiculous pricing of add on features (particularly software only feature additions and GPS for NAZA).
3. DJI NAZA Assistant Software that requires connection to DJI servers BEFORE it will RUN!
I was considering a NAZA until I downloaded the NAZA Assistant and it would not run to let me look at it because it would never connect to DJI servers.


Thurmond
 
#11
Careful guys about jumping to a conclusion, it will probably be wrong. With one down does not make it a bad product, more likely a simple mechanical problem that caused a unstable therefore and uncontrollable aircraft. As noted above, the brain has to have four good controllable motors for it to work. One motor problem will cause the whole thing to be uncontrollable by man or machine. Know this for a fact from personnel experience.
Sure - except this is 2 in as many weeks. I agree, probably one of their motors or props.
Funny thing is, in their FAQ they mention something about if a prop comes off - tells me this is big enough problem that they've noted it in their FAQs.