Naza H motor shut down in GPS mode

[Cleared2Engage]

So here's a question. Has anyone had the motor just shut down while hovering in GPS mode? My 600 ESP did a swan dive from 400 feet while I was looking at the telemetry display on the DX9. I had wanted to know what 400 feet looked like. By the time I realized what was going on, it was too late to auto rotate and it tumbled to the ground. Basically the impact was so bad Im just going to replace the whole helicopter. I doubt it was bearings seizing because it had recently had its annual tear down and all bearings and blades had been replaced. Both batteries (the 2 cell rx batt and 6s 6000 mah pack) were in good shape w full charge prior to flight. It also happened 3 minutes into the flight. Also checked the data logs on the ICE100 esc and I cant find any abnormalities. I dont think the battery came loose in flight either. The wires on the esc were stretched out pretty bad from the battery being flung away from the heli on impact. Scorpion motor also still rotated freely. Im stumped. Anyone else ever hear of this happening? The owner of my LHS said a customer experienced the same thing, but at 5 feet so he was able to save it. If my FC survived the impact, Id like to re use it, but not if this is going to happen again.

[nightflyr]

Never heard of the Naza-H causing this condition....
But if it is a concern to you, you can use the throttle bypass method.

JMHO....
I would check over the entire electrical system for a possible loose connection or damaged wire insulation.
Did you have any cyclic control when the heli was falling?

[StripedGear]

+1 on the bypass..... you must have lost ALL power to the bird or the naza while in atti mode would have done it's best to keep the heli level... so you may not have had power to the naza and the servo's... The same thing happened to me once... I was at about 30 feet and in forward flight when I heard the motor shut off.. the bird came down level and landed in a forward skid slide... this was a trex 600 esp in a MD500 fuse. on a single 6s pack.. no RX pack..... so I still had cyclic power.. I would take a good look at your RX, RX pack, Naza wiring and so on.

[Cleared2Engage]

Everything as far as connections and mechanics were fine. Rx batt and bec are still good. I had no idea if cyclic was working on the way down because the blades came to a complete stop. My best idea is that the motor shut down and lost altitude. The FC sensed a loss of altitude and added collective to bring it back up to its last known altitude. This would naturally kill off any headspeed. And by the time I flipped it back to manual to attempt an auto, the blades were perfectly still.
The reason I never bypassed the throttle was that I fly up to a mile away at times (in a river bottom with nothing to hurt but the unfortunate bush). Ive had complete loss of signal and the heli maintains rotor rpm and altitude for its failsafe. My untested theory is that if I have a loss of signal, the FC wont maintain hover rpm and essentially do what it just did. As far as I can tell bypassing the throttle only allows you to activate throttle hold while in gps/atti modes. Not really a feature I need.
What struck me as odd was when my LHS owner told me about a customers G700 doing the same thing. Still had cyclic and auto'd down from 5 feet.

[nightflyr]

" Ive had complete loss of signal and the heli maintains rotor rpm and altitude for its failsafe."

In the stock configuration this is S.O.P

"My untested theory is that if I have a loss of signal, the FC wont maintain hover rpm and essentially do what it just did."

This contradicts your first statement....
You state you have had LOS and the system went into fail safe and held its position and altitude.

I would take a close look at your connections on your ESC, motor and throttle channel.
By your description your motor shut down but apparently the FC was still active, could possibly be a poor solder connection or a fault in the ESC or some type of motor failure.

Just taking educated guesses here

[Cleared2Engage]

There is no contradiction. If I have signal loss w the esc plugged into the Naza, I know that the Naza is going to maintain that rpm. If my esc is plugged directly into the rx and bypassing the FC, then I dont think the rx will hold the constant rpm like it would if it was plugged into the FC. Again, flight log on the Ice 100 shows everything normal. Motor is good enough to be re used on another project. Cant presume if it was even a connection issue because the esc, motor, battery and helicopter all went different directions on impact. And again, all connections on Naza and AR8000 rx are still good.
If someone can tell me with 100% certainty that bypassing the FC for the esc will still hold rpm after a signal loss, I just might try that. But I cant seem to find any actual data on that.

[Cleared2Engage]

Not trying to be mean, but Im looking for people who have either experienced this and what their fix was, or by some miracle a DJI rep. I wouldnt be on here if I hadnt already checked if the battery was plugged in or not. Ive already been through the tear down and analyze part. Done 6days of speculating and guessing already.

[StripedGear]

Understood man....... If your TX is capable of fail safe mode.. then I would you could do the bypass... if not then no... Maybe due to the terrain your flying in a loss of signal is more pronounced... I wish I could help but it is a head scratcher.... Please let us know the outcome. thx

[Cleared2Engage]

Stripped, you were saying something similar happened. Did you bypass the FC before or after you had the motor cut out on you. Wondering if its a fault of the DJI firmware. No issues of signal loss where Im at. It was just the fact that I had the copter flying about a mile away line of sight. Little things like somebody walking in front of you can actually have an effect at that distance. One of these days Ill switch to a real long range freq.
Not saying I dont appreciate the help, its just that Ive already gone through the wreckage multiple times to look for anything that couldve brought it down. (Linkages, wires, goblins, etc).

[nightflyr]

Originally Posted by Cleared2Engage

There is no contradiction. If I have signal loss w the esc plugged into the Naza, I know that the Naza is going to maintain that rpm. If my esc is plugged directly into the rx and bypassing the FC, then I dont think the rx will hold the constant rpm like it would if it was plugged into the FC. Again, flight log on the Ice 100 shows everything normal. Motor is good enough to be re used on another project. Cant presume if it was even a connection issue because the esc, motor, battery and helicopter all went different directions on impact. And again, all connections on Naza and AR8000 rx are still good.
If someone can tell me with 100% certainty that bypassing the FC for the esc will still hold rpm after a signal loss, I just might try that. But I cant seem to find any actual data on that.

Originally Posted by Cleared2Engage

Not trying to be mean, but Im looking for people who have either experienced this and what their fix was, or by some miracle a DJI rep. I wouldnt be on here if I hadnt already checked if the battery was plugged in or not. Ive already been through the tear down and analyze part. Done 6days of speculating and guessing already.

No worries... I can understand your frustration...

As for... "If someone can tell me with 100% certainty that bypassing the FC for the esc will still hold rpm after a signal loss, I just might try that. But I cant seem to find any actual data on that."
If you setup the SET RPM in GOV mode on your ESC, then set your Tx fail safe to those settings the ESC will maintain its output to the motor.

Word of caution though... if you have LOS, your motor will continue to spin .. throttle hold will not function.
There are risks in setting up in this method.

[TACO88]

I have the Trex 500 and was flying around 80 feet high when the motor (500mx) just died on me. I was flying on ATTI mode and the heli autorotated and landed upright thanks to the Naza. Upon inspection of the motor I found out that the bearings froze. Motor would not even rotate. Replaced the motor with a Scorpion HK-3226-1600KV and been happy flying it.

[StripedGear]

Yes it was bypassed.. In fact I invented the bypass... To this day I still don't know what cause my motor to stop... but if it hadn't been the the naza in atti mode it would have been a bad crash... In any case, like I said about the TX fail safe... Nightflr is correct... I fly at a set rpm so if I lose signal it will hover where it is until it gets a signal.. FYI many members of my club have had the same thing happen at our field and there are only a couple of naza's.... In fact in a 4 week range 5 birds went down... everything from motor shutdown to total FC lose..... all this shit is made in china....

[Cleared2Engage]

Thanks Striped, thats the kind of info I was looking for. So I guess I shoukd think twice about putting this on my 800 DFCpro and making that my long range FPV ship. The only good thing to come out of this is after I wrecked my 600, my girlfriend convinced me to upgrade to the Gob 700. Im thinking shes marriage material.

[StripedGear]

I'm not saying that the problem is the Naza.... the other mishaps were Vbar, 3gx and Ikons... Im just saying signal interference.... Nothing can help you if your motor quits for whatever reason... but setting up the fail safe will will help with LOS..

[Cleared2Engage]

Must have read the last post wrong. Back to square one I guess, lol. Ill more than likely use the Naza Again, just wont be going a mile + out.

[Mark F]

Not sure if this is going to help with Naza H.

With Naza M there have been problems in GPS mode and switching to manual and then right back to GPS solves them. It may be worth a try if someone else has this same issue while in GPS mode to try it.

[Stumblebee]

Originally Posted by Cleared2Engage

The only good thing to come out of this is after I wrecked my 600, my girlfriend convinced me to upgrade to the Gob 700. Im thinking shes marriage material.

Only if she is also willing to pay for it too.