Betaflight 4.0 released

Betaflight developers have released final Betaflight 4.0 version. Whats new?

Betaflight 4.0 introduced the real time ESC RPM feedback, and motor RPM based notch filtering. This is possible because of newly developed Bidirectional DSHOT. It is a new feature in Betaflight 4.0 which enables the flight controller to receive high frequency RPM telemetry for each motor on the ESC motor signal line. It does not require any additional wiring or an additional telemetry back-channel. Each DSHOT frame from the FC gets acknowledged by a frame from the ESC containing the current eRPM.  The RPM filter is a bank of 36 notch filters on gyro and Dterm which takes advantage of this high frequency RPM telemetry data to implement a motor harmonics filter which removes motor noise with surgical precision. Bidirectional DSHOT is currently supported by BLHeli_32 and require an update to the latest firmware. The latest firmware can be found here:

New feature Launch control adds a race start assistance system that allows the pilot to pitch forward and then release the sticks with the quad holding position for the race start.

Launch procedure:

  • Launch Control mode switch is enabled
  • Arm
  • Leave throttle at minimum
  • Pitch quad forward to desired angle
  • Recenter sticks
  • Advance throttle to launch

Video demonstrating this feature:

Switchable OSD profiles is added ability to have a several different OSD layouts and switch between them in the flight. You can assign the layouts to the transitter switches for different flying styles, occasions or other needs.

There is a new ‘Stick Overlay‘ OSD element that shows an overlay of the current stick positions. In order to use it, the font loaded onto the OSD needs to be updated to the latest version (available in configurator 10.5.0 or newer). Good for live view of your sticks right in the FPV feed.

Betaflight 4.0 has implemented throttle based dynamic gyro and dterm filters. Also D term management added. This code cuts D by a specified percentage durning normal flight, and lets D smoothly rise back to normal with rapid gyro moves like flips and rolls. D will also increase little bit during prop wash events. For more information on the feature head here:

Starting from the Betaflight 4.0 there will be much easier for the manufaturers to add their board targets. This is acheived by Unified Targets, so called  ‘one firmware for many flight controllers’ technology. This technology (when the changes in the configurator will be completed) will allow manufacturers to make firmware for any number of boards, or RTF products, available directly in configurator.

You will need the newer Betaflight Configurator 10.5.0, because it has new additional settings and CLI commands specifically for Betaflight 4.0.


Quote from Betaflight 4.0 release page:

“When we released 3.5 in August last year, the number of different targets supported by Betaflight had reached 150, and maintaining them was becoming a major effort and taking up a lot of our time. It became clear that we had to do something. We had been working on changing the architecture of Betaflight to make it possible to use the same firmware for different flight controllers for some time, and so we decided to complete this change before releasing the next version, and that because of this fundamental change the next version would be 4.0.

As we approached the originally set release date for Betaflight 4.0, we realised that we were not quite ready, and we decided to take another three months, in order to be able to complete the work we had started.

So now, here we are, ‘Unified Targets’, as we called the new ‘one firmware for many flight controllers’ technology, is now a reality in Betaflight 4.0. There is still some work left to be done to add support for flashing Unified Targets with their configurations to Betaflight configurator, but once this is done, we will be able to allow manufacturers to make firmware for any number of boards, or RTF products, available directly in configurator.

As you have come to expect from Betaflight, we have picked up a number of new and exciting improvements to the flight performance, like ESC RPM based filtering, D term management with D_min, and throttle based dynamic gyro and D term filtering.

And, again as expected we have added some more, non flight related new features like launch control, OSD profiles, and support for on-board SPI attached RX.

For an extended list of new features see below.

To get the best out of the flight performance improvements, please read these tuning tips.

If you are upgrading from an earlier version of Betaflight, please read the following section containing a list of things that you might have to change in your configuration.

We have tried to make this release as bug free as possible. If you still find a bug, please report it back to us by opening an issue here.

If you want to talk about Betaflight, ask configuration questions, or just hang out with fellow pilots, you can do this in our Facebook group.

Betaflight also has a presence in the Slack messaging platform. Register here, and then come join us in Slack. Most developers hang out there, so this is a great place to talk about the things you are tinkering with in Betaflight, or get help with really complicated configuration problems.

Kia kaha (stay strong)”

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