Back in April 2017, I reviewed the Betaflight F3 Flight Controller by FPVModel. I found it to be a generally excellent FC that had a focus on build quality, sound electrical design and a great set of features.
FPVModel has recently released a new version of this flight controller with an F4 processor, aptly named the “Betaflight F4 Flight Controller“. Since I had recently damaged the old FC in my Chameleon, I took this opportunity to upgrade to the newer version to see how it compared.
Betaflight F4 Changes
The Betaflight F4 flight controller is fundamentally an incremental update to the Betaflight F3 FC. The two flight controllers have more in common with each other than they differ. Among things the two controllers share are pad design and layout, features (integrated PDB/OSD) and the sophisticated six-layer PCB designed to deliver tons of power to all four ESC pads. To prove the point, here is the top and bottom of both FCs, side by side:
As you can see, almost every component on is present on both boards. Following are the major ways the two flight controllers differ:
Probably the most obvious difference is in the name. The Betaflight F4 flight controller uses the popular F4 processor. This raises the processing power bar, unlocking capabilities like 8k/8k with Betaflight dynamic filtering turned on, but throws in a slew of complexities due to UART inversion issues that always crop up with F4 flight controllers – read more about that here. I think this move is a wash – I really do prefer the set-up simplicity that F3 offers and am not sure that there really is a performance advantage offered by the faster F4 CPU. As newer, more advanced filtering schemes continue to be added to the Betaflight codebase (the upcoming Kalman filter being one example), I may be proven wrong. Then again, this FC uses the MPU6000 gyro, which does not support the 32kHz update rate which the Kalman benefits most from anyways.
SD Card – Gone
The Betaflight F4 has built in flash memory. This was the selling point of this FC for me. The Betaflight F3 would have been my flight controller of choice for all of my quads if it wasn’t for the SD card slot. I continue to have card recognition errors an unacceptable amount of time in every quadcopter I fly with that uses SD cards. Admittedly, at this point I have mostly given up trying to use Blackbox at all on these quadcopters — nothing is more frustrating than spending a day at the field trying to gather data to come home to a “Corrupted card” error.
I’ve had lots of feedback from folks who have never had issues with SD cards. That’s fine, and I can totally understand why people like using them. To that end, I really like that FPVModel is keeping the Betaflight F3 around so that we all have a choice between SD card and flash memory. Blackbox is an incredibly important feature for getting your quadcopter “just right”, and I’m glad we all have options.
Other Minor Changes
ESC Telemetry Pads – For folks using KISS and BLHeli_32 ESCs, there are dedicated pads next to the signal input for each ESC which you can wire your telemetry to.
RX Voltage – On the Betaflight F3 FC, you selected the voltage for your RX using a solder bridge. The Betaflight F4 simply has separate 3.3V and 5V output pins.
Voltage Regulator / BEC – The Betaflight F4 is equipped with a BEC which provides up to 1.5A of power for external accessories. FPVModel now recommends you run VTX’s on a separate regulator or using VBAT. The FC BEC should last longer with this change.
So how do I actually feel about the Betaflight F4? I really like it. I could tell that someone put some serious thought into the Betaflight F3 flight controller. It brings every feature a Betaflight pilot would want from a flight controller to the table. The electrical design is superb: soldering to the power pads on this thing are tough — a clear indication of the amount of copper they used to hook everything together. These flight controllers are the only ones on the market I would feel comfortable using by hooking a single power pad up to a 4-in-1 ESC. The Betaflight F4 inherits all of this, and brings a few improvements I was really hoping for to the playing field. Not only that, but at $34, it’s a real steal. I still remember buying my first FCs for $60 — and those weren’t even top of the line.
My only real complaint with the Betaflight F4 is that mounting the ESC power pads on the bottom of the flight controller makes repairs unnecessarily difficult. It can also make installation hard if you attempt to install the ESCs with the flight controller already mounted to the quad. Pro tip: measure the length of wire you need for each ESC and solder all four ESCs to the flight controller before putting the whole mess inside of your quadcopter.
If you pressed me, I could also complain that the Betaflight F4 doesn’t show the attention to manufacturing finish that the F3 had. Specifically, the manufacturer has left on the blemish where the FC’s PCB wafer was cut away from other boards:
This manufacturing relic was filed away (or not originally present) on the Betaflight F3. This complaint is silly, though, because it doesn’t affect anything functionally, and can be easily fixed with a file. One other thing I noticed was that an inductor was positioned improperly on my board:
Again, this does not affect functionality, but it does make me think that the manufacturer may have been cutting some corners that weren’t cut with the Betaflight F3.
Despite these small issues, I think this flight controller may very well be the best one on the market, considering everything. In fact, if you head over to our Flight Controller Buyers Guide, you’ll see it is our new Propwashed Best Value pick. Bravo to FPVModel and the entire development team for this thing!