Ok, the discussion had to be started here as well. What do you guys think of soft mounting the FC and/or motors? I have been soft mounting my FC for a while, and recently started to soft mount the motors. On my kiss setup I first tried with 4 layers of PVC tape and it felt better (at least my little placebo friend in my mind told me so). I then tried with double layer of double sided foam tape, and it felt about the same. I wanted to do a more scientific approach to the whole thing so I did some blackbox logs with my betaflight quad and compared the results. 

The quad is running a Xracer F3 V3.1 soft mounted FC, and I did 3 tests for now:

1. Without soft mounting the motors.
2. 1mm 3D printed 92A flexible filament soft mount.
3. 2mm rubber soft mount made of a rubber mat from a local hardware store.


Soft mounted FC


3D printed 1mm soft mount


2mm rubber soft mounted motors



and the blackbox results:

Roll
      

Pitch
      

Yaw
      



As you can see from the results it isn't much difference in motor vibrations when comparing no soft mount and 1mm 3d printed soft mount. But when we look at the 2mm rubber soft mount, it actually looks like it has reduced some motor vibrations

I raised this in another thread, but I'll repeat it here. It seems to me it would be difficult to keep the props in exactly the same plane with soft mounting. The FC can certainly compensate, but is there a way to look at the difference in gyro compensation (if that's the correct term) between hard mounted and soft mounted?

Edit: Or is that what I'm looking at (I'm novice at BlackBox logs)?

Did you turn gyro debugging on? I can't see the labels on images on mobile.

Gyro_debug_mode is set to notch, and this is the pre-notch gyro data

(16-Feb-2017, 01:52 PM)sloscotty Wrote: I raised this in another thread, but I'll repeat it here. It seems to me it would be difficult to keep the props in exactly the same plane with soft mounting. The FC can certainly compensate, but is there a way to look at the difference in gyro compensation (if that's the correct term) between hard mounted and soft mounted?

Edit: Or is that what I'm looking at (I'm novice at BlackBox logs)?

You are looking at a spectrogram from the gyro in each axis. Most of the stuff happening on the left side on the graph is the quads movement, and most of what you see between 100-600hz is motor noise/vibrations

Very interested in this too. Luckily a fellow fpv pilot that we usually meet at our favourite spots has a 3D printer, he's gonna print these for me, they were designed by rcg member airmaxx23 who reported superb results using HK flexible filament and 40% infill... looking forward to trying them out on my rage240.

Met Häns again today, he brought me these:

Gonna test a bit on different quads/motors...

Two things to remember when soft-mounting motors:

1. Don't push screws all the way in, leave some room for the mount to absort vibration (not too loose that it can physically moved by hand)
2. USD LOCTITE! make sure to use loctite on your mini quad motor screws, since they are not "dead tight"

Got around to test a bit... FC hardmounted and one single motor with 5545 prop on empty frame. PIDs completely zeroed.
What surprised me: it already sounded smoother... Seems to make a difference especially in the lower frequency range.

Roll axis raw gyro comparison:




Pitch axis raw gyro comparison:




I used the 1.4mm 35% infill pads. Arm holes are big enough to put a piece of shrink tube on the screw, and also cut a "washer" from a thicker shrink tube. Will put more details in my 240mm rage build thread later.

Ohh my, this sport/hobby is turning in to seeking total perfection, like Formula1
I like it but its also confusing lol

I'm very curious about soft mount. I rather preffer not use it.
Soft mount on FC has some sense.
In motor I don't think so. Because motors can't be screwed thight, how will they act in hard maneuvers? They will moved back an forth.
Of course in Black Box reads will be smooth, but what with flight characteristic.

(07-Mar-2017, 10:28 AM)cebulator Wrote: I'm very curious about soft mount. I rather preffer not use it.
Soft mount on FC has some sense.
In motor I don't think so. Because motors can't be screwed thight, how will they act in hard maneuvers? They will moved back an forth.
Of course in Black Box reads will be smooth, but what with flight characteristic.

My motors are screwed down thight. If they are too loose, you will get oscillation problems

(07-Mar-2017, 10:33 AM)oyvinla Wrote: My motors are screwed down thight. If they are too loose, you will get oscillation problems

Yeah i think too, if they're too loose it would be worse than without. But if done right, imho it's much better fighting the problem at the source, than having the whole frame resonate so that even soft-mounting the fc will become difficult to get right.

i've recently started soft mounting all my motors. i found that it helped with my raceflight builds so i started putting them on all my quads. 

also oyvinla, when you did your initial testing, it looks like your motors weren't really producing a lot of vibration to begin with. i think maybe put a bent, or unbalanced prop on and then try the same test. see if the results changes.

I use small m3 rubber rings. It feels like less vibration and keep the screws in place while the motor is detached.