hey guys, new to fpv, been flying for a couple of months.

i crashed into a puddle with my eachine wizard and fried 2 esc's and broke 2 motors.

so i replaced them with racestar 30a v2 esc's and emax rs2306 2400kv white edition motors.

after doing this i have mid throttle oscillations, at first i thought it was pids, but after changing them to every value possible i couldnt tune it out.

so far i have tried:

• soft mounting fc
  
• soft mounting motors
  
• replaced a motor that had a crappy bearing (still oscillating)
  
• replaced props with various brands (still oscillates without props on)
  
• calibrating esc's (throttle up, plug in battery, throttle down)
  
• making sure everything is tight
  
• not overtightening emax motors bolt that holds the bell on
  
• tried lowering my p and then running 0 on i and d and it still oscillates. 
  
• made sure there is no bolts touching the windings
  
• added a silicone pad for the battery to sit on so it doesnt move
  
• using tpa
  
• callibrating accelerometer
  
• change min throttle
  

current specs on the quad:

hardware

• NAZE32 6DOF REV6
  
• 1500mah 4s battery
  
• hq glassfibre 5x4x3 props
  
• emax rs2306 white editions
  
• racestar 30a v2 esc's
  
• runcam owl
  
• eachine tx801 vtx
  
• tbs triumph rhcp antenna
  

software:

[color=rgba(255, 255, 255, 0.6)]2017-07-04 @ 16:21:31 -- MultiWii API version received - 1.21.0
[/color]
[color=rgba(255, 255, 255, 0.6)]2017-07-04 @ 16:21:31 -- Flight controller info, identifier: BTFL, version: 3.0.1[/color]
[color=rgba(255, 255, 255, 0.6)]2017-07-04 @ 16:21:31 -- Running firmware released on: Oct 18 2016 10:35:52[/color]

• multishot protocol
  
• medium motor timing
  
• demag compression low
  
• damped light
  
• min throttle 1050/1070(tried both)
  
• min command 1000, max 2000
  
• ibus
  
• gyro freq: 4khz
  
• pid loop: 4khz
  

PIDS:
 roll: 
P 45
I 40
D 20
pitch:
P 55

I 50
D 22
yaw:
P 70

I 60
D 0

D setpoint weight: 2
D setpoint transition: 0.3
mid throttle: 0.50
throttle expo: 0.00
tpa: 0.15
tpa breakpoint: 1650

cycle time: 280
cpu load 38%


i have read that rev6 gyro's are quite sensitive with noisy motors?

here is a vid of the flight: 
it is a bit more dramatic through dvr

any help would be greatly appreciated, i think i have spent about 3 weeks now trying to figure this out, it doesnt help that i am still learning everything either

Looks like you have gone through everthing I would know to try. Hopefully someone more experienced than myself will be able to help.

(04-Jul-2017, 08:30 AM)Drone0fPrey Wrote: Looks like you have gone through everthing I would know to try. Hopefully someone more experienced than myself will be able to help.

i hope so too, it's driving me crazy!

if i dont set it on fire, i think the next troubleshooting stages will be:

low pass filter
new flight controller
new frame to stop resonation

which im putting off because theres a lot to learn haha

Hi Earcl, Welcome to intoFPV!

I am going to ask this question just because if I am thinking it someone else might wonder as well...

When you changed out motors and ESCs did you do all 4 corners or just the 2 damaged ones?
If you just swapped out the damaged ones, are the new ones the same as the old ones?

My assumption is that all 4 corners probably have the same motors/escs but I ask because I've seen someone mention that motors or ESCs can be different from batch to batch (kind of like RAM in a computer). If they are the same parts but different shipments maybe check to make sure firmware is the same on ESCs... Also depending on FC version if it's not the most current give an update a try before buying more stuff... Afterall it couldn't hurt anything

As DoP said, that's about the extent for me as well lol... good luck!

(04-Jul-2017, 11:53 AM)Carl.Vegas Wrote: Hi Earcl, Welcome to intoFPV!

I am going to ask this question just because if I am thinking it someone else might wonder as well...

When you changed out motors and ESCs did you do all 4 corners or just the 2 damaged ones?
If you just swapped out the damaged ones, are the new ones the same as the old ones?

My assumption is that all 4 corners probably have the same motors/escs but I ask because I've seen someone mention that motors or ESCs can be different from batch to batch (kind of like RAM in a computer). If they are the same parts but different shipments maybe check to make sure firmware is the same on ESCs... Also depending on FC version if it's not the most current give an update a try before buying more stuff... Afterall it couldn't hurt anything

As DoP said, that's about the extent for me as well lol... good luck!

changed out all 4 stock eachine wizard motors and esc's  out for aftermarket

i have had a breakthrough though!

about 3 days ago i upped the D gain on pitch and roll, and it seemed fine with minimal oscillations, i only tested for a minute though.

the day after, i crashed within the 1st few minutes and it went back to oscillating again. at the time i thought i just didnt fix it because i didn't try it properly the night before and i didn't crash that hard, looking at it last night i noticed one of my motor bells was bent, switched it out and the oscillation is amost gone!

so i did fix it, but then unfixed it when i crashed lol.

im assuming the rest of the oscillation is motor noise getting into my sensitive flight controller

thanks for the help guys

Great stuff! I am glad you've got it mostly resolved and know what's left to work on to finish it off.

You might also want to test each esc/motor slowly through the mid range in motor tab to see if it's not a single esc stuttering in a certain area. I even had a brandnew kiss24a that did this, couldn't fix it.

PS: You didn't describe how exactly you softmounted the FC. If it's using those rubber mounts then it should be fine, however if you're only using o-rings above and below the FC you might want to increase the hole size a bit (or use m2.5 type screws) and also bevel the holes a bit, to make sure the o-rings get centered well and the screws can't touch the FC anymore.

I have the same issue as you with emax 2306 both on a 5" and 6" setup.
The builds are very different, only thing these two builds have in common are the motors and realacc rubber soft mounting for FC, so I started to google emax 2306 and found your post.
https://www.banggood.com/4-PCS-Realacc-M...35527.html

The two quads had exactly same issue, one had 24A kiss and the 30A racestar 4in1.
I tried with both kiss FC and betaflight omnibus F4 FC same thing. I tried 3 FCs in all because I have been an idiot and set fire to my FCs of other reasons

Try fiddle with your notch filters, it really made the difference for me.
For me the oscillation frequency was 110hz and 220hz, I set the lower notch filter (notch 2 in betaflight) to 165hz and lower cut 85hz.
Also lower LPF filters to 90 hz.

Before these filter I could barely not fly the quad, after I could increase the P and D sufficiently to get super tight grip and no hot motors.
Actually now I only fly with that notch filter, because I have soft mounted both motors and FC. If I remove this filter, it imediately becomes unflyable.

Check out Josua Bardwells videos on notch filters, they are very informative:

also check his guides to black box analysis in generel, then you can find you nemesis frequencies.

happy flying