DJI NAZA H Nodding Forward/Backward

[Khosravi]

Hi, I am having a nodding issue with my NAZA H. With my old blades, I could get a nice stable GPS hover with a forward/back gain of around 65%. But with my newer higher quality blades, I cannot lower the gain any more than 40% (software won't allow below 40) and still get a slight nodding in the forward/backward direction. Altitude and left/right gains are perfectly fine at around 90%, I just have no idea about the forward/back gain. Heli flies awesome in manual mode, Atti and GPS having nodding issues. I recently upgraded to faster servos so there's no way servo speed is the issue here as they are .09 sec servos on cyclic.

When I say nodding, I mean rocking back and forth with an oscillation speed of about 1-1.5 seconds.


I can take pictures of my setup when I get home from work, hopefully an expert with the NAZA H could help me out.

-Chris

[Khosravi]

Still having forward/backward oscillations after putting faster servos in and reinstalling the newest firmware. What am I missing guys? I had a rock solid GPS hover with the older V1.04 firmware, but can't with the newer V2.00

-Chris

[Valkman]

When you upgraded to rev 2 did you go through all the setup again? You are suppose to. My cyclic was way different after the upgrade. Maybe you have too much cyclic throw after the upgrade causing the rocking.
Also what heli are we talking about?

[Khosravi]

Yes I went through setup again and made sure everything was moving in the right direction. However, I do believe I have too much cyclic! I didn't think that it would have a negative affect on performance so I never bothered to adjust it. I'll make the change and post the results soon.

The helicopter is a Trex 600 stretched to a 700. The frames are custom made from G10 in order to have a camera mount in the front.

-Chris

[Valkman]

Going through "all" the setup means a bit more than just checking if everything is moving in the correct direction!

As I said,
"My cyclic was way different after the upgrade. Maybe you have too much cyclic throw after the upgrade causing the rocking."


By the way that's a nice rig you have.

[Khosravi]

Solved the problem! Thanks to Valkman. I had way too much cyclic throw. With the stock Trex 600 bell cranks, I was unable to get into the desired range even in the DJI Assistant Software. So I did the direct-to-swash mod and now I'm in the desired range (~6.5 degrees). Just did a test flight this morning and she's holding better than ever now

-Chris

[Valkman]

That's good news. Did you change the frames with the mod?
Put up a picture for others to see I'm sure seeing as it is still a new product others will have the same issue.

[Khosravi]

Frames have always been my custom ones. Only thing I changed was removed the stock Trex 600 bell cranks. I now run a direct-to-servo link. It seems as if the Naza was designed for direct servo linkages rather than going through an amplifier device (bell crank). Before when I had the bell cranks on I was getting 12 degrees of cyclic movement when the new Naza firmware called for 6.5 degrees. In the assistant software I had the cyclic slider adjustment all the way down. Now with the bell cranks removed, I get around 6.8 degrees of cyclic which is WAY better than before but could be a tad bit better I suppose.


-Chris

[Valkman]

Wow 12 deg of cyclic movement I thought mine was bad at 9. What was it before maybe DJI need to be made aware of this. I have the Chaos 600 stretched ( looks like you have the same SK3 motor ) and I moved the ball links in one hole on the servos and get 6.5 now. I did think about moding the frame to go the direct servo route but it's ok the way it is.
I have my gain on elev at 55, ail 80, pitch 120 ( I think). I may notch up the pitch next flight.

[Khosravi]

Originally Posted by Valkman

I have my gain on elev at 55, ail 80, pitch 120 ( I think). I may notch up the pitch next flight.

Are those the autopilot gains or the flybarless gains? I have my flybarless gains at 140 for aileron and elevator. For autopilot I think I'm at 75 for forward/backward, 85 for left/right, and 90 for up/down.

Yup that's the SK3 motor It's the 560kv version since I'm running 10s.

-Chris

[Valkman]

Yes autopilot gains. My flybar is also at 140 all round.
I have the 480kv motor, 12s. I put ceramic bearings into it worst thing I ever did. They lasted about 10 flights!

[Khosravi]

Originally Posted by Valkman

I put ceramic bearings into it worst thing I ever did. They lasted about 10 flights!

Interesting, my stock motor bearings are still holding up just fine so far!

I'm waiting on a new ESC to arrive that does active free-wheeling since my Castle Creations HV 85 heats up when flying with a 50% throttle curve (all I need for AP). That way I can do 15 minute flights with it without worrying about heating issues.

-Chris

[Valkman]

Your ESC would heat up at 50%. Better to have it between say 75% and 90%. Your lucky it did not blow.
I would go down a pinion or two if I was you.
I damaged the original motor taking it apart to do a review video so I put the ceramic ones in. They went but I had a spare motor there so I took the ones from that. That reminds me to buy more!
Keep an eye on your motor temps if you plan on flying that long with that motor. And measure from below the pinion not the cooler outside can.

[Khosravi]

Yup, that's why I'm switching to a different ESC. I don't need a high head speed and I like being able to fly 15 minutes using partial throttle. Motor gets warm, but not hot after 10 minutes (haven't flown beyond 10 minutes with my current ESC)

-Chris

[Khosravi]

Just test flew my new active-freewheeling ESC and it works great! I felt no temperature difference from before and after flying. On the other hand, I think I need to change the motor timing as the motor was hotter than I'd like it to be.

-Chris

EDIT- Just did a test flight with my SK3 motor running with 6 degree of timing. Gets warm now instead of hot. I can step the timing down 1 more setting to 0 degrees but not sure what that would do? I need to research more on ESC timing and switching frequencies.

-Chris

[Valkman]

Different ESC have different timing with the same motors. My SK3 wont even spool up with 5 deg and I tried on 2 ESC's and two motors..

[Khosravi]

Update. Still loving my Naza H. Haven't had any nodding issues since removing the bellcranks.

[Valkman]

Nice setup. Here's mine on it's last flight.

DJI Naza H setup showing position hold (1 min 31 sec)

[Mapoff]

This is an old post but I recently had the same problem. I started with a Flybar and went through the setup once and it was perfect in manual, atti, and gps. Then I wanted to try going FBL. I didn't restore factory settings, but only went through the setups and picked FBL. It flew perfect in manual. In Atti and GPS it was doing a fast rocking and almost out of control ticking back and forth like a metronome at 200bpm. I figured the new FBL head was the problem so I went back through the setup to switch back to Flybard. Still same rocking. I restored factory defaults, and now still same rocking. Its very scary in auto. It seems to drift where ever it wants as well.

When I first bought it, everything was rock solid even in horrendous winds. DJI doesn't provide support only the resellers and I'm not sure how much they would know or help. I bought it from Century Heli which is one of their authorized retailers. Any suggestions on the movement?

[Khosravi]

For me, the problem was too much cyclic. Back when I had the problem, I was using a dedicated airplane radio so it was much much harder turning down the servos. So I mechanically adjusted some things on my Trex 600 to much smaller cyclic amounts. 6.5 degrees is all you need and it says so in the Naza Assistant.

-Chris