Betaflight Tuning for Mini Quad

by Oscar
Published: Last Updated on

There is so much new stuff to learn in Betaflight 3.4, I am sure it’s a bit overwhelming for a lot of people! In this tutorial I will try to explain how I tune my quad with the latest Betaflight firmware in the simplest way possible.

A lot have changed in the latest Betaflight, and you should “re-tune” your quad for the best possible performance. This guide has been updated for Betaflight 3.5.

Betaflight Tuning Guide

The official tuning guide for Betaflight 3.4 is a bit daunting but definitely worth a read if you have time. It also explains the new changes in Betaflight 3.4: https://github.com/betaflight/betaflight/wiki/Tuning-Tips-for-Betaflight-3.4

FeedForward

Check out this article to see what Feed-Forward does. Here is how you tune it:

If you want sharper response and more control, increase F gain. If you want smoother stop of a flip and less prop wash, increase D gain. If you have oscillation on Yaw axis, you can try higher F and I values, then drop P to maintain the responsiveness while keeping oscillations caused by P gain to a minimum.

The range is 0 to 2000, but you will never need 2000, if you do put it on 2000, the quad might just freak out when you touch the sticks… Even the default value of 60 felt a bit too sensitive for me, so I reduced it down to around 50.

Enable iterm_relax

set iterm_relax = RP

Apparently not only too much P and D can cause bounce-back, I gain can too! By enabling “I-term relax”, It can reduce bounce-back at the end of flips or rolls.

“I-term relax” also allows you to increase I term by 50% or more makes your quad fly more “locked in” in extreme conditions without feeling too “stiff”.

Increase I gain by 50% from BF 3.3

Throttle Boost

With “Throttle Boost”, when you move your throttle rapidly, Betaflight will spin up or slow down the motors faster than before. This makes an unresponsive or heavy quad a lot more responsive, and feel more like a smaller/lighter quad.

Throttle Boost is a bit like a dynamic throttle curve, it exaggerates throttle changes. However it only works with rapid throttle movement, and has no effect when you change throttle slowly.

If you are using RC smoothing filter, “Throttle Boost” can also cancel out some of the latency caused by that.

set throttle_boost = 10

Make some rapid throttle movements when tuning this value. You want to land on a number where you get very responsive throttle without surging, overshoot and feeling over-sensitive.

Heavier quads, and quads with weak motors need higher Throttle Boost value. On my freestyle quad (weighs 550g+ with gopro and lipo), I have it at 15.

If you want a quad with smoother throttle you want to lower this, for example 3 to 5.

RC Smoothing Filter

RC signal gets updated regularly, if you look at blackbox log you will find “stepping” in the original RC signal. Stepping in the RC signal results in rougher running motors.

RC Smoothing filter can smooth out these stepping. It can even reduce spikes and sharp edges from rapid stick inputs, your motors will run smoother and cooler.

Previously we used a method called “Interpolation”, but it has relatively high latency. In Betaflight 3.4, we are given a new method called “Filter” which has less smoothing, but also less latency. The benefit is that the aircraft feels more responsive and connected to your sticks.

Having said that, you may or may not feel the difference, but less delay is always a good thing.

set rc_smoothing_type = FILTER
set rc_interp = AUTO
set rc_interp_ch = RPYT

If you notice a change in rapid stick response, consider adjusting “setpoint weight”, “throttle boost” and P gain to compensate.

Adjust setpoint weight, throttle boost, P gain

SBUS or FPort users should set their radio link to D16 mode using 8 or fewer channels on the Taranis Model Setup Page.

This allows faster channel update by not sending the 9th to 16th channels (9ms vs. 18ms), and this fixes all the problems with RC smoothing filters. The only downside is that you can use only 8 channels, but that shouldn’t be a big problem for most racers and freestyle pilots.

Tuning PID

The default PID values in BF3.4 are too low for all of my builds, especially D gain. They work okay built feel a bit sloppy, so I had to increase them quite a bit.

You may copy PID from the previous BF version. The wiki tuning guide suggests to increase P, I and D values by up to 20% from your previous tune to match the same level of responsiveness.

If you want to try tuning PID from scratch, check out my PID tuning tutorial.

Filter Changes

There are now 4 low pass filters, 2 for Gyro and 2 for D term. These are all enabled by default. All of them are using PT1 and the new “dual filters” seems to work pretty well, so you only need to play with the filtering frequency depending on the setup and condition.

The lower the number, the higher level of filtering and latency. Lower filter frequency if you have oscillation or hot motors. You can turn the filters off by setting them to 0 (zero), don’t do this unless you know what you are doing.

When it comes to filters, it can get complicated. Not everyone has the time to play with blackbox and filters. If so just try the suggestions from the Betaflight Wiki.

Average build

set gyro_lowpass_hz = 120
set gyro_lowpass2_hz = 300
set dterm_lowpass_hz = 80-100
set dterm_lowpass2_hz = 160-250

Clean build

set gyro_lowpass_hz = 150
set gyro_lowpass2_hz = 400
set dterm_lowpass_hz = 100
set dterm_lowpass2_hz = 250

Noisy / Beat-up quad

set gyro_lowpass_hz = 90
set gyro_lowpass2_hz = 180
set dterm_lowpass_hz = 70
set dterm_lowpass2_hz = 140

Enable Dynamic Filter

It’s best to leave Dynamic filter enabled. Yes, it adds delay, but it’s useful when you are constantly bashing your props which changes the noise frequency. Dynamic filter can target that noise automatically and keep it down. So I think this should work well for most people. Only turn it off if you know what you are doing.

Conclusion

I hope this guide was easy to follow, feel free to share, comment and ask questions. I will try to keep this guide up to date.

Edit History

  • Jul 2018 – Article created
  • Aug 2018 – Added info about Feedforward

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15 comments

Diego 17th January 2019 - 4:09 pm

Hello!
I would like to know what are the recommended filter values for a 7″ setup?

Regards.

Reply
doctorquad 16th January 2019 - 1:06 pm

Would the same rules (PIDS) be applicable for twitchy 90mm or 120 mm miniquad running cheapo motors etc?
2 Sell. Matek f411 Mini ? (hint!)

Reply
Zac Johnson 30th December 2018 - 12:55 am

Hi Oscar,
any tips on tuning out the “rough ride” bumps? Can’t get my quad to just fly smooth in a straight line, it feels very rough, but otherwise flies great.
Thanks, your articles have always been very helpful for me.

Reply
_nd345 28th October 2018 - 4:02 pm

Does all this apply to Butterflight too, or should i not do this?

Reply
Oscar 6th November 2018 - 12:41 pm

Not sure, never tried Butterflight.

Reply
David Hannigan Jr. 23rd August 2018 - 7:24 pm

You said above; “….SBUS or FPort users should set their radio link to D16 mode using 8 or fewer channels on the Taranis Model Setup Page.”, but gave no indication why you suggest that. Please lemme know what I’m missing?

Reply
Tim Hall 14th August 2018 - 10:07 pm

I am new to quads and purchased an Armattan Rooster, It has the CL_Racing F4 FC, I was able to get it to bind using CLI commands but now it will not exit bind,I tried set spektrum_set_bind_autoreset=off but in says invalid, please help. Also I have my receiver set up but it will not Arm. Thanks

Reply
Kauly 1st August 2018 - 7:01 am

This is for brushed mini quads? I guess not. Will be nice if you make an updated betaflight tutorial for bushed quads.

Reply
Malte 31st July 2018 - 8:42 pm

This is a great help for all of us new to the hobby’s intricacies. Thank you very much for this awesome post.

Reply
Christian 26th July 2018 - 2:17 pm

Hi Oskar,

thanks for this nice post. I am wondering how we can reduce prop wash in Betaflight 3.4. In Version 3.3 and earlier we disabled the notches and changed the filter type to PT1. But in BF 3.4 this is already the default. With my 4″ quad with BF 3.4 I have prop wash issues. How can I reduce them?

Thanks

Reply
Nicoco 29th July 2018 - 5:07 pm

Hi, same here. 3.4 fly really well but i also have more prop wash. I lost and don’t know how to tune wash out.

Reply
Oscar 31st July 2018 - 9:14 pm

Increase P and D :) the Default is on the low side :)

Reply
Robomk 24th July 2018 - 7:47 am

Hallo Osacar

Thank you for your work. Very nice post. I hava a small question. Do you think you should incrase the I-Gain by 50% as well from the default PID in 3.4 after enabling iterm_relax?

Reply
Oscar 24th July 2018 - 6:45 pm

“increasing I gain by 50%” is only for PID tunes from previous Betaflight firmware, default PID in 3.4 should be fine. But try different PID if you have time and see which flies better for your setup :)

Reply