Removing jello and vibration from Betafpv X95 v3
Ever since I got the Betafpv X95 v3 I’ve been trying to find the way to make it fly without all the issues that this drone is plagued with out of the box.
Let me start by showing what are those issues:
Clip 1: Betafpv X95 v3 jello - Out of the box
Clip 2: Betafpv X95 v3 Propwash - Out of the box
The unit I got is the DJI version of this drone. It comes with a Caddx Nebula Nano, which almost everyone complains about.
In my out-of-the-box review, I said I didn’t find it too terrible, mainly thinking about the colors. The nano is very saturated, and the colors look unrealistic, but in my opinion, the quality of the image is not that bad.
Anyway, the first change I did was to test with a full DJI camera, just to check, and it just happened that a lot of the jello disappeared just with this change.
The mount I use for the DJI camera, which is a bit bigger than the nano, is the one included in the package, so nothing fancy, no TPU 3D printed part as many are suggesting, or even any kind of o-ring in the connection of the camera mount, just replaced one camera by the other.
I don’t know if it’s the problem is the camera itself, or the weight of the camera, or the mount, but the reality is that most of the jello disappeared just with that change.
The vibrations are a completely different topic.
The drone has a lot of vibrations, as you can see in the following video, which despite using reelstready go you can see many occasion where the drone wobbles so much that even RSGo can't do anything about it.
Clip 3: Vibration all over
In order to try to remove all those vibrations I started to play with the tuning.
My plan is to use this drone for cinematic shots, together with a naked GoPro, so I didn’t mind doing some changes that could affect the punch of the drone, which is not much in general, but I didn't mind decreasing it even more.
I used the changes proposed by the Betaflight presets found in this link: https://github.com/betaflight/betaflight/wiki/4.2-Tuning-Notes
Which mainly are:
Cinematic (For slow rate turns only, may feel a bit 'dull' otherwise)
set iterm_relax_cutoff = 5
set rc_smoothing_auto_smoothness = 40
set ff_interpolate_sp = AVERAGED_4
set ff_smooth_factor = 50
set ff_spike_limit = 50
set ff_boost = 0
set feedforward_transition = 70
set yaw_lowpass_hz = 50
set throttle_boost = 2
set throttle_boost_cutoff = 10
set dyn_lpf_dterm_curve_expo = 8
set gyro_rpm_notch_q = 900
set iterm_windup = 75
The following tuning suggestions may help minimise minor random wobbles in HD footage:
- disable D_min,
- set D about 20% above P, using the P:D ratio slider
- set TPA to D only, to start at your cruising throttle value, and increase the cut percentage a little
- set the D lowpass expo value as high as possible (you'll be limited by mid-throttle D noise) (with the extra D, you may need more D filtering, e.g. 2 clicks left on the D filter slider)
- use about 20% less P than your normal freestyle tune, just barely enough to provide basic P stability.
- and about half the default I on pitch and roll
- high FF transition eg 0.7
- make sure the ADC is not ticked in the hardware settings of OpenTx
- use Actual Rates with centre set to 10-50, expo to 0, and your usual max rate. Actual with zero expo gives a soft centre with quicker return to normal responsiveness out of centre. Transition and/or deadband may not be required when the centre sensitivity is very low.
The last part of this quick setting was not perfect for me, so I keep playing a little bit with it until getting to this:
With these changes I'm not getting a lot of prop wash, and the vibrations has decreased to a somehow acceptable point.
It’s worth mentioning that I’m doing all this configuration with a 4S 650 mAh battery and the naked GoPro on it all the time. I tested a 850 mAh but the drone got too heavy and with the changes I have done before it was very difficult to control it.
The motor's temperature is still ok, it could be that the fact I’m testing all this with -10 C (14 F) outside helps, but I will check that later when the temperature increases.
The flying time with the 650 mAh battery is about 3.5 min, probably I'll get half a minute more when the days are a little bit warmer.
Here is the raw recording from the DVR of all this changes done:
Clip 4: Betafpv X95 v3 after PID tuning
And here is the same video stabilised with reelsteady and edited a bit.
Clip 5: Betafpv X95 v3 Final Result - Reelsteady Go stabilised.
All in all I think this changes made this drone much nicer for what I was looking for, which is filming with a naked GoPro. The drone won’t be able to do much if any freestyle moves, but at least I can get some decent shots now.