What is new in Betaflight 4.2

Another version of Betaflight is getting ready for prime time - version 4.2. In this article I want to take a look at the changes and see what interesting things have been added - especially focusing on things that might be interesting for brushless whoops and micros.

To see what has been added to the newest version, I am filtering by milestone and closed PR’s in the Betaflight github repository. Since I want to focus on new features I am mainly going to focus on the following tags: RN:IMPROVEMENTS and RN:MINOR FEATURE.

Version 4.2 is due on the first of may, and seeing that there are only a handful of issues open, I am pretty sure that this target will be met.

  1. Dynamic Idle
  2. NFE Race Mode
  3. Rate Types
  4. OSD Logo on Arm
  5. Battery Sag Compensation
  6. Other

Dynamic Idle

Technically this feature has already been introduced in 4.1, but until now it has not seen much love in my opinion. Also the UI for this feature has just been added to the Betaflight configurator, so I thought I will mention it here.

You can only use dynamic idle with bi-directional DSHOT or ESC telemetry - the FC need to know the motors RPM.

Dynamic idle basically improves the handling on low RPM situations like for example flips, rolls and dives. Everything where you abruptly decrease throttle.

To learn how to tune dynamic idle, check out the Betaflight Wiki.


NFE Race Mode

Not fast enough race mode. People who are familiar with Silverware probably also know what this mode does. This is an acro - level mode hybrid. Level mode is used for the roll axis and acro mode is used for pitch.

This feature will only work in level mode and can be enabled via CLI:

set level_race_mode = ON

Source: Betaflight #9481

Rate Types

There are now different “rate types” that aim at making the rate settings more intuitive. Until now, RC rate is a linear relation between stick deflection and degrees/second. Super rate exponentially increases the curve and Expo is applied on top of that to flatten the curve more in the center.

This means with the current method of setting rates the center sensitivity is dependent on Super Rate and Expo.

One of the new rate types (ACTUAL) tries to make this more intuitive. By introducing the values “Center Sensitivity”, “Max Rate” and “Expo”. I really like this nomenclature: Max Rate - as the name suggests - is the maximum degrees/second (multiplied by 1000 so a value of 1 equals 1000 degrees/seconds). Center sensitivity is the same thing for 120 degrees/second you would set it to 0.12. Expo is applied on top of all of that.

There is also a simulator to show the difference between the current rate settings and the ACTUAL type settings.


OSD Logo on Arm

Up until now, the OSD logo has only been shown on startup. This can now also be shown when the copter is armed. I am sure this will get a well used feature especially for the cases where pilots are only posting DVR footage.

# Enable set osd_logo_on_arming = ON # Set duration to 0.5 sec (max 5 seconds, value = 50) set osd_logo_on_arming_duration = 5

Source: Betaflight #9244


Battery Sag Compensation

The initial motor output is reduced in the beginning. As the battery starts to sag the motor outputs are boosted. This should make the quad “feel” the same way over the whole flight time of the battery. It is important to monitor the battery voltage via the OSD, since the feel of the quadcopter is only supposed to change once the battery is severely discharged.

This has been reported to work especially well for 1S builds.

Source: Betaflight #9561


This is obviously not a full list of all changes, if you are interested in more details I would like to encourage you to check them out for yourself on github.

There have been almost 270 features/improvements/bugfixes that found their way into the upcoming version of Betaflight - pretty impressive if you are asking me.

Chris is a Vienna based software developer. In his spare time he enjoys reviewing tech gear, ripping quads of all sizes and making stuff.

Learn more about Chris, the gear he uses and follow him on social media:

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