In my latest racing drone build, an Armattan Chameleon, I was faced with a tough decision that I think a lot of pilots are dealing with these days: do I use the Omnibus F4 flight controller or the new Betaflight F3 flight controller. As of Spring 2017, these flight controllers are the best on the market in my mind. Since I recently did a psuedo-review on the Omnibus, I figured this build would be an excellent chance to compare it to the Betaflight F3 FC.
The Betaflight F3 flight controller touts an impressive resume. It is marketed as supporting every feature the Betaflight firmware has to offer – including all the new features of Betaflight 3.1. Here is a list of the notable features:
- Built-in OSD with voltage and current sensing.
- Built in PDB rated for 100A continuous, 160A burst.
- Onboard 5V voltage regulator rated at 3A.
- Full DSHOT support of all modes.
- The best drone racing gyro on the market, hooked up to the processor via high speed SPI.
- SD card slot for blackbox logging
- Pad layout specifically designed for low-mess wiring, including edge-mounted pads for all ESC connections.
- Boot button.
Nice list! It checks every box I have for flight controller expectations, as laid out in our Flight Controller Buyers Guide. Let’s see how it actually performs, though.
As always, we recommend you draw out how you want things connected before attacking anything with a soldering iron. Even if you don’t use the drawing, the thought process that goes into making it will help make sure you get your build done right.
The Betaflight F3 Flight Controller has a pretty straightforward soldering alignment. All of the pins and pads are neatly labeled and located in logical places. Unlike most flight controllers or PDBs, though, soldering work must be done both on top and bottom of the board. I recommend you start with the bottom.
Bottom of the Board
The main thing you’ll be soldering into this location is the power leads for all 4 of the ESCs. A pair of leads is located in each of the four corners of the flight controller. When soldering on ESCs, you have a couple of options. The best option is to desolder the power leads from the ESCs and solder them directly to the Flight Controller. The reason is that with the bottom of the flight controller installed in the frame, it is extremely difficult to solder wires from the ESCs directly onto the flight controller. This is what I tried in the build, and it was an excercise in frustration:
It is better to go the other way around. You want to install the flight controller on the frame with 4 sets of power leads pre-soldered and sticking out. From there you can then clip the wires to size and install the ESCs separately. This will make the installation much easier.
You will also want to bridge the appropriate pads for selecting the RAM voltage and the RX voltage:
RAM is the voltage that is sent to the video transmitter. You can select either the battery voltage (VBAT) or 5V to send to the VTX, but you must put in a solder bridge regardless. Failing to do this will leave your VTX unpowered. For my Chameleon build, I will be running VBAT to my VTX. I suspect most of you will be as well. The only VTX I know that uses 5V is the LaForge VTX.
The RX voltage jumper pads selects the voltage sent to the pin labeled “5V/3V” next to the “DSM2/SBUS” pin. If you are using an FrSky transmitter, you will want to bridge the 5V pad. For Spektrum guys like me, you will want to select 3V.
Finally, the battery positive lead is soldered to the rear side of the bottom board.
Top of the Board
While there are many through-hole pins which can be accessed from both sides of the board, I recommend you do most of your work on the top of the board. This will make it easier to work on if you have problems since the board will be very difficult to flip over once installed.
First up, you’ll want to install the ESC signal wires. Like the power leads, each ESC has it’s own pads in each corner of the flight controller. Installing the signal wires to these pads should be very straightforward.
Next you’ll hook in the electronics. If you are going to use pin headers and servo connectors, solder them on now. Otherwise, go to work directly soldering your wires to the through holes. At a minimum, you’ll want to connect your serial RX, video transmitter and FPV camera.
The Serial RX should be hooked up to the labeled pads in the bottom of the pin headers on the right of the board.
The video transmitter will be hooked into VOUT/RAM/AGND. VOUT is the video feed, RAM is the voltage powering your video transmitter, and AGND is an isolated, noise-free ground source for your video feed.
The FPV camera is a bit more complicated. The Betaflight F3 FC doesn’t provide a power/GND source for the FPV camera so you should power it with the Vcc/GND output from your VTX. The video wire from your FPV camera should be hooked up to VIN on the flight controller.
From here, you’ll want to hook up any extra accessories you’ll be using. Pads and through holes for the buzzer, RSSI, and LED strips are provided.
And once again – solder the negative battery lead onto the top of the board.
Here is my flight controller fully hooked up:
Software set-up of the BetaFlight F3 is fairly typical of any Betaflight flight controller. Before you do anything though, you should find an SD card to use with Betaflight. We have received reports that you must flash the Betaflight firmware with an SD card installed for Blackbox logging to work. I had a lot of trouble finding a working SD card, but eventually was able to get a new one from Amazon working. Make sure you format the SD card with FAT32 before installing it in your flight controller.
You’ll want to flash Betaflight 3.1 or newer to take advantages of all the awesome new features found in that version of the software. This board uses DFU to flash firmware, which can be a pain to use on Windows computers. The Betaflight documentation has a good guide on how to get this working.
Once you have the right version installed, you’ll want to do the same basic configuration you do on all Betaflight flight controllers. Check out our Betaflight configuration guide for details on this.
You’ll also probably want to set-up your OSD. We have a great guide on this which can be found here.
I’ll start by saying that I’m a fan of this flight controller. It packs everything I want from a flight controller and power distribution board into one 35mmx35mm square while retaining an absolutely fantastic pad and pin layout. It flies great on my Chameleon – though it is living an easy life with soft mounted motors and rubber isolators below the FC. I love the built in current sensor. This was a major missing feature on the Omnibus and I’m glad to able to fly again with a battery usage readout at all times.
That being said, it is not the perfect flight controller for everyone. Following is a list of concerns I have about the controller.
First up is pad layout. All the ESC power pads are located on the bottom of the flight controller. This makes installing and removing this flight controller very interesting. You really want to give this some thought before you do any part of your quadcopter build if you are using this quadcopter. But once it’s built, this fact also means that the quadcopter is going to be hard to maintain. The flight controller is physically strapped to the frame by the four ESCs being soldered to it. If you want to remove the FC for maintenance or changes, you’ll need to de-solder at least 2 ESCs from it. Not fun!
For this reason, if you’re still a beginner and crashing a lot,you may want to consider a different flight controller with a separate PDB.
SD Cards Suck
My next gripe is the SD card. I was lured into thinking this was a good thing by the terribly slow download rate of Blackbox logs from the built in flash memory on most flight controllers. I’m getting the feeling I was tricked though – SD cards are not the answer for this hobby. First of all, the first 3 SD cards I tried to use with this flight controller simply did not work. I formatted them several times in different ways and just could not get them to work. The fourth card I used, a brand new 8GB card from SanDisk, finally worked. Even so, the card frequently comes unseated while flying, causing the logs to not get recorded. It’s no wonder a large part of the Betaflight F3 flight controller discussion thread on RCGroups deals with getting SD cards to work.
Then there’s another layer of problems that most people probably don’t properly associate with the SD card. This flight controller takes much longer to boot up than other comparable flight controllers. You’ll notice this when you plug the quadcopter in for the first time: the ESCs don’t emit their “armed” tone until about 5 seconds after powerup. All my other quadcopters arm within 1 second. The reason for this is almost certainly the SD card because if you disable the SD card feature the problem disappears. This is likely caused by the fact that the flight controller has to perform diagnostics on the card every time it boots up. I’ve regularly had this fail, causing my quadcopter to go into a state where I cannot arm it. The only way to fix the problem is to power cycle it. Lame.
Morale of the story: if I could trade my Betaflight F3 flight controller for an identical flight controller with onboard flash memory instead of the SD card, I’d do it in a heartbeat. Blackbox is not an optional feature for me – it is a requirement. It is the only way you can get your quadcopter perfectly tuned and it almost doesn’t work on this board because the SD card feature is so deficient.
So it’s been a couple of months since this flight controller was released and you still cannot purchase it off of backorder. I personally had to wait a month to get mine. I’ve heard that the unique design of the board means that most factories cannot produce it. That’s probably great news for the designers – cloners will have a difficult time reproducing it – but it sucks for us consumers. It’s tough for me to recommend this board to friends with such a long waitlist. For example, what happens if you receive a defective board or break it while building? You’ll be waiting another month? All while the extremely competitive Omnibus F4 sits in stock at every major racing quadcopter retailer in the world. It’s a tough sell. Hopefully this problem works itself out soon.
Omnibus F4 Comparison
I think the majority of the folks who are looking at this flight controller are probably trying to decide between it and the Omnibus F4. I’ve now built quadcopters with both flight controllers and feel qualified to compare the two. There are a few notable differences between them:
- F3 vs F4 processor. The Omnibus has the better processor, but I don’t honestly think it makes a difference in flight performance. Maybe there is a future where the F3 flight controller becomes obsolete like the F1s did last year. I don’t know but I’m not betting on it.
- Build in PDB on the Betaflight F3. The Omnibus needs an external PDB to enable you to split power to the ESCs. This is a blessing and a curse. It means that the Omnibus is more versatile: it is the best FC to use if you are going with a 4-in-1 ESC for example. It is also easier to work on and replace. However, it is missing the current sensor that the Betaflight F3 FC has, which means you’ll never know how much charge your batteries have left while flying.
- Build quality. There’s no doubt about it – the Betaflight F3 is the superior board in terms of build quality. It costs twice as much but feels and looks twice as nice too. My omnibus had some crooked connectors and a few questionable soldering points. The Betaflight F3, on the other hand, looks and feels like a work of art. I particularly love the silk screen Betaflight hornet on it.
- SD card – On the Omnibus, you have a choice between an SD card port and internal flash memory. On the Betaflight F3 you have to live with the SD card. As I mentioned above, I’m not a fan of SD cards in quadcopters. If I have to use them, though, I prefer the enclosure offered by the Omnibus to the floating SD card port on the Betaflight F3 flight controller. I just know this thing is going to wear out and become unusable in very little time.
- Availability and price – the Omnibus wins by a mile here. It can be had for $25 from many retailers and will ship out instantly. The Betaflight F3 on the other hand is eternally out of stock and costs $40 at the cheapest.
One interesting consideration is that the Omnibus variant of flight controller keeps coming out with new “revisions”. It seems to be getting cloned much like the SPRacingF3 and Naze flight controllers. DYS has come out with a very interesting offering recently called the “DYS F4 Flight Controller“. It seems to have an identical featureset to the Betaflight F3, but without the SD card. I may have to check this out in my next build. Stay tuned..