F1, F3, F4, G4, F7 and H7 Flight Controller Processors Explained

by Oscar

F1, F3, F4, G4, F7 and H7 are the different processors in FPV drone flight controllers. This article explains the differences between these MCU, the pro’s and con’s, which I hope it will help you decide what FC to get.


What are F1, F3, F4, G4, F7 and H7 in Flight Controllers?

F1, F3, F4, G4, F7 and H7 are the different STM32 processors (aka MCU – Micro Controller Unit). The processor is the brain of a flight controller (FC), similar to the CPU in a computer.

There are currently 11 series of STM32 MCU, from faster to slower processing speed they are: H7, F7, G4, F4, F3, F2, F1, F0, L4, L1, L0.

STM32 F1, F3, F4 Processors on flight controllers

STM32 F1, F3, F4 processors on flight controllers

Processor Processor Speed Flash Memory* SRAM
F0 (STM32F051) 48MHz 256KB 32KB
F1 (STM32F103) 72MHz 128KB 96KB
F3 (STM32F303) 72MHz 256KB 80KB
F4 (STM32F405) 168MHz 1MB 192KB
F4 (STM32F411) 100MHz 512KB 128KB
G4 (STM32G491) 170MHz 512KB 128KB
F7 (STM32F745) 216MHz 1MB 320KB
F7 (STM32F722) 216MHz 512KB 256KB
F7 (STM32F765) 216MHz 2MB 512KB
H7 (STM32H743) 480MHz 2MB 1MB

* This is the internal flash memory inside an STM32 processor chip, it’s used to store the flight controller firmware codes. Don’t get confused with the flash memory on the flight controller that is used for blackbox logging, which is a separate chip.


F0 chips are often used in BLHeli_32 ESC, however it’s too slow / has too little memory for flight controllers. I thought I would mention it anyway.


The first 32-bit flight controller ever used on a mini quad was the CC3D which had the F1 processor (F103), followed by the iconic Naze32 which runs Baseflight.

However F1 flight controllers are considered outdated as they are no longer supported by most firmware including Betaflight (since 2017) due to hardware limitations – low clock speed, not enough memory for storing the firmware, lack of floating-point acceleration hardware and UART’s.

F1, F3, F4, F7 flight controller

Naze32 FC


F3 processors (F303) were first introduced to flight controllers in 2014. It’s more powerful than F103, and it was the obvious choice to replace F103 as they are pin-to-pin compatible. Some advanced users even replaced the F1 on their CC3D with an F3 chips for the better specs.

F3 MCU can be found on many popular FC’s back in the days, including the X-Racer, Betaflight F3, and the KISS FC V1.

However, as the Betaflight firmware keeps growing, we ran out of resources on F3 processors eventually and support for F3 FC was dropped in 2019.

F3 flight controller

Betaflight F3

To summarize, the F3 has the following advantages over F1:

  • Similar clock speed on paper (72MHz), however the F3 is better at handling floating point calculations thanks to the FPU (aka “math co-processor”). This allows an F3 to run floating point based PID controllers significantly faster than the F1, it allows faster looptime
  • F1 boards normally only have 2 UART’s compared to the 3 offered by most F3 flight controllers. In addition, and possibly more importantly, the newer F3 boards provide a dedicated UART for the USB port (VCP). F1 users have to avoid connecting any peripherals to UART1 in order to retain this slot for PC connection. Effectively this means that an F1 board has only 1 UART for additional hardware, whereas an F3 board can usually utilize all 3 UART’s for extra devices
  • All UART’s on an F3 processor have native inversion, which means you can run SBUS and Smart Port directly without doing any “un-inversion hacks”

Some F3 chips are almost pin-to-pin compatible with the STM32 F1 chip used on most F1 FC, in fact someone commented on my blog, that he successfully replaced the F1 chip with an F3 on his CC3D, and is now running 8K looptime on it (thanks to the SPI Gyro used on this FC).

Note the size of flash data storage used for Blackbox logging doesn’t depend on the processor. It’s actually determined by a separate memory chip on the flight controller.


F4 flight controllers were introduced shortly after the F3, and quickly gained popularity due to its processing power advantage. Unfortunately, F4 FC don’t play well with Frsky receivers, as they don’t have build-in inverters, and so additional hardware (or DIY hacking) is required for Frsky SBUS, SmartPort and F.Port.

There are two main F4 variants used in FC – F405 and F411.

F405 is more powerful but bigger. You normally find this in 30x30mm flight controllers.

The F411 used in FC normally has a smaller package but shares the same architecture with F405. However it has lower CPU speed, less flash memory and fewer UART ports, but it’s usually cheaper. You normally find this in whoop style FC, 20x20mm or 16x16mm FC.

Popular FC’s with F405 are Kakute F4 AIO, Mamba F405Matek CTR AIO, FlightOne Revolt and BrainFPV RE1.

F4 FC - Matek CTR

Matek CTR F4 FC

  • The processing speed of the F4 processor is more than double of the F1 and F3 (72MHz) at 180MHz, while it also commonly has a dedicated FPU which is what gives the F3 the advantage over the F1
  • It’s possible to run 32KHz Looptime on a F4 board compared to the Max 8KHz on an F3
  • F3 boards generally only have 3 UART’s, but some F4 FC’s offer up to 5
  • Betaflight’s new feature “Dynamic Filter” is very labour intensive for a processor, giving the increased speed of the F4 another clear advantage
  • F1 and F4 processors do not have built-in inversion like F3 and F7. Without additional hardware on the board, you’re required to do the inversion hack (getting uninverted signal) if you you want to run Frsky SBUS or Smart Port

Is faster Looptime better? Well that’s a whole different discussion. Check out this article about whether 32KHz looptime is better in terms of performance.

Why F4 doesn’t work with SmartPort natively:

SmartPort is a half-duplex protocol, meaning the S.Port wire is bi-directional that data is sent and received in the same wire (though not at the same time, that’s why it’s only “half”).

F3 and F7 STM MCU can handle half-duplex protocol internally in the chip itself, so you can connect SmartPort directly to these flight controllers without any modification. But F4 doesn’t have this capability.

Although SmartPort is also inverted, F3 and F7 can invert the signal coming in or going out internally, so no problem there.

F4 does have the half-duplex capability too, but it doesn’t work with inverted signal without an external circuit that does inversion for it bidirectionally.


Fpv Drone Flight Controller Stm32 G4 Processor

Although STM32 G4 chip is not the fastest, or has the largest memory, it’s the newest chip used in flight controllers, it even came later than the mighty H7. The first G4 flight controller is the KISS G4 flight controller made by Fettec, released in October 2021.

It’s a better replacement to the F3 and F4 MCU, even more useful as we are currently in a chip shortage. The G4 comes with a math accelerator for enhanced flight performance and has better power efficiency.


F7 FC is more powerful than F4 and they are slowly taking over the market. It has more than of processing power, RAM and flash memory for the current version of Betaflight. Plenty of UART ports, with built-in inverters for all UART’s which is user-friendly for Frsky receivers.

Just like F4, there are a few different variants for the F7 MCU.

STM32F745 is a common F7 processor in FC, very decent clock speed and memory, however it also has a pretty large package, so if there is a lot of feature you want to have on the FC, the F745 probably wouldn’t fit.

STM32F722 is a smaller F7 MCU but with less flash memory and RAM, still it’s enough for the current Betaflight. In fact the F722 is the most popular F7 chip in flight controllers as they are also cheaper than F745.

STM32F65 is the most powerful F7 processor used in FC, in almost every aspects. However it’s even bigger and more expensive than F745, therefore it’s not a very popular option.

There are more options of F7 flight controllers than F4, for example the Kakute F7, CLRacing F7, Betaflight F7 FC and SP Racing F7.

  • F7 is a faster processor (216MHz vs 168MHz of F4)
  • The F7 processor has superscalar pipeline and DSP capabilities – which means the F7 is a better platform for future flight firmware development, allowing the developers to further optimize the flight controller algorithms
  • F7 boards allow for more UART’s, all with built-in signal inversion capability. Considering all the peripherals that we can use nowadays – serial receiver, Betaflight OSD, SmartAudio, SmartPort Telemetry, GPS, Camera control etc, DJI OSD, Blackbox logging, more UART’s are always handy to have!

At some point, It was necessary to overclock F4 if you want to run 32KHz in Betaflight, while the F7 processor is fast enough to handle 32KHz without overclocking.

Looptime is also limited by the type of gyro (IMU) and their maximum sampling rate. For example MPU6000 has a maximum sampling rate of can 8KHz. If you want to do 32KHz, you would have to use IMU with higher maximum sampling rate, such as the ICM-20602.

Some designers decided to put two different gyros in their F7 flight controllers. One is the proven, low noise gyro such as the MPU6000, and the other is a faster gyro that can do 32KHz such as the ICM-20602. This allows the pilot to choose whichever gyro they want to use.


H7 is the fastest processor listed here, offers a 480MHz clock speed, compared to F7’s 216MHz. Yet the higher clock speed doesn’t make a difference in flight performance currently. We still have room to grow with F4 and F7 flight controllers, it will certainly come in handy when we start doing 8KHz looptime with RPM filters alongside other calculation intensive features in the future.

There are different H7 chip variants used in FC, Seriously Pro Racing is the first to release a flight controller with H7 processor – the H7 EXTREME. It’s based on STM32H750 processor – the cheapest and smallest H7 chip, with only 128kB of flash memory (same as the F1). And that’s really not enough to store the current Betaflight codes. To work around this, they store the Betaflight code on external memory, i.e. on an SD card. The codes are then loaded to the RAM when it’s running (and so it doesn’t matter even when SD card falls out during flight). To update Betaflight firmware, you will just update the firmware files on the SD card, no more flashing and so there won’t be any DFU driver issues anymore. It’s an interesting and unique concept.

Diatone’s H743 and Holybro Kakute H7 BT both uses the more powerful H743.

Diatone Mamba H7 Fc Flight Controller Top Close Up

So, which processor should I get?

Basically, all F4, F7, G4 and H7 flight controllers are fine with Betaflight, at least for the next year or two according to Betaflight developers. Here are my FC recommendations. However, absolutely avoid all F1 and F3 FC boards as they are no longer supported by Betaflight.

If the flight control firmware codes grow larger in the future, some processors will have an advantage as they have more flash memory (at least 1MB) such as STM32F405, STM32F745, STM32F765, STM32H743. Some F4 and F7 processors only have 512KB, such as STM32F411, STM32G491, STM32F722. These are perfectly okay for now and the foreseeable future, and I am sure managing memory space will be something Betaflight try to focus on and support them as long as they can. The lack of memory is why F1 and F3 FC’s have gone obsolete in 2017 and 2019 respectively.

Processor clock speed is actually not as important as it used to be in 2022. Running the fastest possible 32KHz PID loop frequency was all the hype back then, but now it seems the hobby has settled for 4KHz – 8KHz because our drones actually perform just as well if not better at the slower rate. The F4 processors can totally handle 4K, if you prefer 8K, then one of the F7 and H7 would be a better choice. But honestly, for me it’s very hard to tell the difference between 4K and 8K looptime in the air so in my opinion it really doesn’t matter that much.

The lower clock speed requirement is especially true as BMI270 gyro is becoming more popular in recent months. The BMI270 is currently cheaper and more widely available than other IMU. Although it’s slower – sampling rate is only 3.2KHz in Betaflight (so your PID loop frequency is limited up to 3.2KHz as well), performance is actually on par with the faster, tried and tested MPU6000.

We can anticipate technology moving toward faster processors, which will provide capacity for more exciting features and peripherals, and the capability to run more sophisticated software filters and algorithms that can really make our drone to fly amazingly. If you can afford an F7 or H7 flight controller, go for it, it would be more future proof for sure. But if you are tight on budget, the cheaper F4 would be totally fine right now.

The other thing to look out for when shopping for a flight controller, is the number of UART. FC that are designed for smaller drones like Tiny Whoops tend to have fewer UART (e.g. 2 or 3) due to the lack of space. Normal size FC normally have 5 or 6 UART, which should be enough for most people.

What happened to F2, F5 and F6?

The only STM32 chips we have seen used in flight controllers are F1, 3, 4 and 7, those who have a curious mind might wonder why they skipped F2, F5 and F6?

First of all, the F2 is more like an older version of the F4 and as such does not have integrated signal inversion. This, in conjunction with the next-in-line F3’s faster calculation from the built-in “floating point unit” made it natural for developers to just skip F2.

STM32 F5 and F6 simply do not exist.

STM32 Chip Naming Convention

STM32 chips have names like this: STM32F405RGT6 or STM32F745VGT6

Let’s break it down and see what those letters and numbers mean.

STM32 is a family of 32-bit microcontroller integrated circuits by STMicroelectronics.

L1, F4, F7, H7 etc, the letter indicates the type of the chip (or applications):

  • L – low power
  • F – foundation or high performance
  • G – mainstream
  • H – high performance
  • W – wireless

The number indicates the core:

  • 0 – Arm Cortex M0
  • 1- Arm Cortex M3
  • 2- Arm Cortex M3
  • 3- Arm Cortex M4
  • 4- Arm Cortex M4
  • 7- Arm Cortex M7

The next two numbers indicate the line.

The next letter indicates the number of pins, for example:

  • C – 48
  • R – 64 or 66
  • V – 100

The next number or letter is flash size, for example:

  • B – 128KB
  • C – 256KB
  • E – 512KB
  • G – 1MB

The next letter is package: H – BGA, T – LQFP, U – VFQFPN.

The next number is temperature range, 6 means -40 to 85℃.

Edit History

  • Oct 2015 – Article created for F1 and F3
  • Oct 2016 – Updated F4 info
  • May 2017 – Updated F7 info
  • Jun 2017 – updated news about “Betaflight will end support for the F1 FC”, and added a column for flash memory in the table thanks to Boris B.’s idea
  • Aug 2017 – updated info about the missing F2, F5 and F6
  • Oct 2017 – edited by Tom BD Bad, info about some F7 FC having 2 gyros
  • Oct 2018 – updated my thoughts about F7 FC
  • Feb 2019 – Betaflight Developers to drop support for F3 FC
  • May 2019 – added info about H7 FC
  • Aug 2020 – added info about the different F4 and F7 chip variants
  • Jan 2022 – added info about G4
  • Sep 2022 – revised recommendations based on new hardware and software requirements
  • Oct 2022 – added STM32 chip naming convention

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Alex Harivel 13th December 2022 - 6:25 am

Thanks a lot oscar

Tehllama 1st October 2022 - 5:10 pm

The F722, and even F411 are still more than capable enough (for late 2022, and well through 2023) for the complete flight envelope capability.
Particularly for combinations like F411 with BMI270 IMU on an AIO (ESC + FC) hardware set, the ability to run 3.2kHz looprate with bidirectional DShot is entirely adequate. The only real limitation of the F411’s has been there all along, very limited UART space and that pin allocations from some manufacturers aren’t very good.
Similarly, the F7X2 line is capable of running at maximum performance without issues, and managing the memory space is still going to keep these boards functional and relevant for a really long time, to where I would still actually recommend these boards as solid future-proof options. The plethora of available UARTs and no need to worry about inversion make these excellent targets.

SugarK 1st October 2022 - 3:57 pm

Ahh the f411 and the f722 memory issues are gona be sorted in 4.4 so as one of the Betaflight devs I’m gona push against not recommending them. They will be supported until they are incapable of running the code. Flash space for any chipset is about to become a non issue

Jan Post 1st October 2022 - 3:20 pm

BF also recommends STM32F411, STM32G491, STM32F722. We will breathe new life into them in the future, so they will be supported for years to come. Please ask the devs first before sharing “fake news” :)

Jan Post 1st October 2022 - 3:23 pm

This sounds a bit harsh, sorry. I didn’t mean to. But I think it’s important for everyone to know that the F411 and F722 are not at all at the end of their life.

Ygrek 30th September 2022 - 6:39 am

Hi Oscar!
H7 (STM32H743) have 2 MB Flash, not 1

Oscar 30th September 2022 - 10:35 am

thanks, yea i got confused by RAM :)

Alexander Fedorov 9th March 2022 - 1:37 pm

Hi Mate! You can also add Kiss FCFC ULTRA to H7 section.

Jacob Hughes 26th February 2022 - 11:50 pm

Why are most Fc’s with DJI plug-in compatibility using an F4 processor? Why can’t I find DJI plug-in FC with an F7 processor?

Oscar 27th February 2022 - 1:35 pm

There’s a chip shortage, manufacturers are currently having a hard time finding affordable F7 chips. That’s why many are now using H7 and G4 chips as well.

Matthew Saigon 18th January 2022 - 8:55 am

people start talking about F411, F722 Not having enough memory. it’s ok to use now, but might not good enough in a near future. especially for boards with built-in SPI ExpressLRS receiver.

Sergey Larionov 30th August 2021 - 12:59 pm

Your flight controller table is great! But I build model airplanes. Is there a similar table for fixed wing flight controllers?

Victor Wild 15th January 2022 - 2:32 pm

Excellent and immediately understood,but can you tell me why my Matek F722 and Matek F405 flight controllers will show a Crossfire Nano receiver working in the receiver tab of Inav 4.0, but, do not when I connect an ELRS receiver, which is connected in the same way as the Crossfire Nano (TX to RX and RX toTX) with the port and receiver tabs set accordingly. The Elrs receivers are working as shown by return telemetry on the transmitter. I have been trying to find a solution to this problem for weeks and am almost at the point of reverting back to the overpriced Crossfire receivers.

Yours hopefully Vic Wild

Mel 15th July 2022 - 10:18 am

Whats better between f7 and g4?? Most aggresive??

Oscar 15th July 2022 - 11:16 am

F7 is faster and has more memory and will be more future proof but performance wise i doubt you will notice much a difference

Azik 6th September 2019 - 2:38 pm

The H7 controller on SP Racing H7 Extreme runs at 400 not 480 MHz. The benefit of that particular FC isn’t about having the fastest controller but rather a true sensor fusion technology that Betaflight 4.1+ can utilise. Faster processing is needed to handle two gyro data streams and be able to run multiple RPM, dynamic and other filters at high rate.

I would consider and recommend that particular board for its near perfect low noise level, high quality components (like separate VREGs, the latest BMP388 barometer) and convenient features like built-in mems microphone, the fastest SD Card connection you can possibly get allowing to log synchronously with loop time as well as built-in flash memory, 7 UARTs and some other things.

AL 20th July 2019 - 11:41 pm

Hello Oscar,
Good day

I always read your post for guidance and to get some expert’s knowledge I am new to this hobby I started building a plane using Mini Talon with Matek F22 Wing. While soldering the pin headers I accidentally snapped one component it’s the 6 pin black thing on the upper right corner of SD card slot I don’t know what it is. Can you help me figure out as I need to replace it. Can you also write about this F7 flight controller. Thank you


Charles 3rd July 2019 - 6:44 pm

Hi Oscar,
Big fan of your blogs and appreciate the wealth of knowledge you compile and share with drone hobbyists around the world. Question, I am building a drone controlled by a computer instead of a rc receiver. Currently I send commands to a pixhawk FC via UART from an onboard computer. Is there non pixhawk based FC’s you suggest (with beta flight or clean flight onbaord) that can accept simpler control commands like pitch/roll angles or rates via uart instead of sbus? or is sbus/ppm/pwm the only way to command simple pitch/roll angle or rates, and its not possible via uart?

Oscar 15th July 2019 - 4:33 pm

No, not possible.

Wolfman 23rd June 2019 - 12:57 am

I have several quads using a F3 flight controller. Should I use Betaflight 3.5 or 4.0 ? Filtering is better on 4.0 but it also needs more resources (memory and CPU) which are limited on F3 MCU.

Jon Scott 29th May 2019 - 12:47 am

Hi Oscar, would love to know if these faster FC’s use much more power, MORE POWER (as Tim would say), or is it in significant. Seems to me that the NAZE32 with good software are as good as you need for park crashing and this faster Hz speed is smaller legs running faster. Cooler electronic run, the better and longer they last.

Oscar 30th May 2019 - 5:11 pm

Power consumption by the FC is negligible in a 5″ quad.

stanley sanders 23rd December 2018 - 2:50 pm

I have gimbaled coaxial contra rotating propellers on a tail sitter platform like Pogo. Can you recommend an autopilot for my platform?

Oren 22nd October 2018 - 4:50 am

I have some old F1 boards, is there a stabke release i can use on them CF or BF doesnt matter.

From what i remmber i think that CF 1.11.0 or 1.13.0 were stable on F1, can you confirm ? recommend ?


Oren 22nd October 2018 - 4:42 am

Thanks Oscar, this was very usefull for me.
Still what I canot find on the web is a list of stable release (BF or CF) for each of the legacy MCU i.e. F1 and F3.

I have many old parts which i want to make usable again, but i dont know which one of the releases where stable (best) for the F1 mcu.

Currently new versions that I have installed on F1 mcu looks unstable on the F1.

From what i remmber i think that CF (cleanfligth) version 1.11.0 was good for F1.

Some other say that 1.13.0.

I think it would be use full to share stable releases for old equipment.

Thanks Oren

Chris 11th October 2018 - 12:07 am

here i am reading an article i read 3 years ago, and its still super useful, thx!, lol.

Jonathan Shore 23rd September 2018 - 1:31 am

Hi I was just wondering if it was possible to flash betaflight 3.5 on to kiss version 2 F7 stm32f 722 chipset. As it does not show up as a Target under betaflight Target list

Oscar 1st October 2018 - 4:36 pm

no i don’t think that’s possible yet.

Andrew 30th April 2018 - 12:00 am

Hello, do you know if i can connect an F7 FC with an raspberry pi? Via USB?

Mighty 23rd March 2018 - 8:25 pm

What is the power consumption of of FC? A little chart would be good showing load and idle wattage at 5v.

Chris C 14th December 2017 - 5:05 pm

You mentioned the “Dynamic Filtering” feature a bunch of times. What exactly is it? Also, what do you need to do if your UART doesn’t invert automatically like on the F4?

Chris 9th December 2017 - 12:04 am

Can the Betaflight F4 support a hexacopter? If so, what pins do I solder the signal wires to for motors 5 and 6?

Vlad XXX 7th December 2017 - 10:50 am

Hey, the F1 and F3 are probably not named from Cortex M0 – M3 M4 core family directly because F1 is M3 and F3, F4 are M4

A bit confusing, I know

Oscar 12th December 2017 - 1:53 pm

LOL you are right! i got confused there!

Taylor 23rd November 2017 - 2:34 am


I learned how to fly on a F4 Flight Controller. If I made a duplicate build with an F3, would I notice a difference in flight?
With duplicate rates.

Oscar 28th November 2017 - 2:15 pm

If you use Dynamic Filter, you would be only able to run 2K/8K looptime at most i think. Whether you can notice a difference? that’s hard to say!

Im Uk 20th November 2017 - 2:52 am

F3 with 216 MHz would be interesting. Although ST is very low tech than Samsung here, I think it is well within ST’s capabilities, using the same process.

Richard F 6th November 2017 - 6:47 pm

F7 flight controllers are currently running slower in betaflight 3.2 then F4 processors right now, due to bad optimization, or a bug. Don’t know about other flight software though.

everton mendes schlickmann 11th October 2017 - 9:21 pm

Oscar Your posts are always the best…
I’m Looking for a board to my quad QX9 frame. Maybe some F4 with OSD and Current sensor.
Thanks for help

Ardalan Ghazi 16th August 2017 - 7:32 am

Typo: F4 has higher processing speed at 168MHz vs 72MHz of F3. It’s possible to run 32KHz Looptime on F4, but not on F3; Both F3 and F4 can handle 8K or less looptime very well, but the F4 (YOU MEANT F3) leaves you with less CPU load to run other features. Especially now with the latest “Dynamic Filter” feature which is quite processing intensive, F4 definitely has an advantage in that regard going forward

Oscar 21st August 2017 - 2:36 pm

LOL I think that’s an misunderstanding, I mean to say F4 can have a lower % of CPU load so it can run more features at the same time.

BorisB 21st June 2017 - 12:56 pm

You forgot to mention the flash space from F3 vs F1, (256kb vs 128kb) which plays a huge difference in terms of features being developed on that platform ;)
The current code base is way too big to fit any of the modern features on F1;s

Oscar 25th June 2017 - 4:44 pm

Thank you Boris! that’s a very good point! I have added a new column now in the table

Mike 28th December 2016 - 9:53 pm

I have a wizard x220 with the FS-16 tx. It came with the F3 6DOF fc. It came from banggood with yaw problems. In the process of attempting to correct it with beta flight lost factory settings on tx. Any help on binding it to the FS-IA6B receiver? any help is greatly appreciated. First racing drone upgrading from toy quads. Thanks again.

Scott 24th May 2017 - 2:27 pm

You should have got a bind plug with your setup, plug the bind plug into the RX ch1 or ppm I think it is, power quad up, now with your finger on the bind button switch on your tx

Garvit 5th October 2016 - 7:49 am

Hello, I am thinking about making a quadrotor with contra-coaxial motors or a simple hexa copter. I have a mission, but will be flying with RC only. My query is, at the time of selection what are the parameters of the vehicle that needs to be considered? Also, motors or size of the vehicle or weight, etc., anything like that needs to be considered while selecting the FC? Please suggest me an FC for the given requirement and I want FC with lowest integration required to be done or the one whose coding can be done easily or easily available online.

Thanks. Your site is full of information.

Indy 25th June 2016 - 10:00 pm

HI Oscar,
I’m a big fan, I appreciate your reviews and articles a lot.
I used several naze 32 rev 5 as well as a few F3. I experience drifting problem sometimes after a few minutes, especially changing modes…
I wish to get something more reliable but not too expensive.
What would you propose today?
x-racer F303 v3, slyline F3+OSD, motolab cyclone??? Anything else? Lot of choice nowadays…

Anyways thanks for soir work…

Oscar 30th June 2016 - 1:32 pm

I would suggest the XRacer, because that’s the one I used and I am very happy with the performance.

Juan 23rd June 2016 - 3:51 am

Hi Oscar
I was building my first quad using the sp racing f3 acro and manage to damage the + vbat pad. The board works fine when plugged to cleanflight but I get nothing when plugged to a lipo..
I already resolder everything and nothing changed so i tried plugging a lipo directly to the vbat pads and still nothing..is there any other way to power the board other than the vbat pads?
But away thanks your videos and blog have been really helpfull..

Chris 6th September 2016 - 6:35 am

I believe the one red wire coming from number 1 esc will power up your board no problem. At least mine does

Michael 8th September 2016 - 3:44 pm

You don’t power the board from the vbat pins, they are for the board to read the battery voltage and either display it via an OSD or allow you to set up a buzzer to warn you when it is getting low. The board is powered from either a 5v BEC which may be built into your power distributton board or from an ESC if the ESC has a BEC. You will be able to tell if it does as it will have 3 wires coming from it to a servo plug. You then supply the board with 5v to any pin on the middle row of ESC connections and a ground to any pin on the bottom row (or outer edge if you have the soldered vertically).

Russell Holt 16th June 2016 - 7:14 pm

I was wondering if there was a difference in SoftSerial speed between the F1 & F3 (I’m using an SPR3 Deluxe right now and i’m thinking of using 19.2kbs on SS for my GPS. the quad re-build is still on the workbench, but using this config, i’m able to get 3D connectivity on my GPS (up to 13 sats inside) … but i was warned that the use of SS with the iNav Flight software may cause data dropouts.
when i asked about data, i was given information that related to the F1 that had data dropouts, and was hoping that using SS on an F3 would probably be an improvement over the F1 being that the calcs were faster & therefore could maybe handle the interrupts (if that’s what they’re called) from the GPS without a problem.

btw – appreciate all you do for the Quad world – i’ve referred to & made use of several of your Discussions, Videos and “blogs” – thank you.
Russ from Coral Springs, Fl USA

Nick 29th April 2016 - 11:04 pm

After buying a “true cleanflight” SPRacing f3.. Cuz I want to support the designers … Anyway the acro board flew great… After a couple weeks a small branch jumped out at my quad.. Voodoo 210 and I hit the ground from about 10 feet… Nothing close to the torture I put my poor naze 32 rev 5 through… My very next flight my quad just dropped mid flight like a sack of potatoes… After inspecting.. Both whate plugs were missing from the board… After many many attempts to have a simple question answered… Can I run my sbus reciever off one of the other uarts… I was referred to rcgroups… And I don’t have 6 weeks spare time to search rcgroups…. So after a couple hrs I said screw it and bought a mini… My mistake… I had to install software from Queen flight to be able to update the board with the latest firmware which took two days to figure out how to do not that I’m an idiot but there was nobody to tell me how did I needed to do that so Massive Rc on their product description page has a link to tell you how to do that so I did it I updated the board went to go connect to the board and it would not connect I had to go back in uninstall all three programs so that I could connect to the board after all of that it would not read my receiver it is now sitting on the floor in the corner of my junk file I bought in a F3 copy that has worked in my quad through 100 crashes and works just perfectly just FYI

Heller 27th June 2016 - 4:00 am

Let’s eat, grandma!

Let’s eat grandma!

Punctuation is very important.

Derrick 30th October 2016 - 1:13 am

I had ripped off those aswell, and its micro soldering. but u can solder wires directly to those tiny metal pieces. at least I did to get Xbox working again.

Bryan 24th December 2015 - 2:25 pm


Thanks again for the great info. Proving again and again that you have the best quad info resource on the web.

Merry Christmas. I’ll continue learning from you guy

Oscar 25th December 2015 - 8:20 pm

Thanks for the support Bryan, Merry Christmas to you too :)

Steve 15th December 2015 - 10:09 pm

Hi Oscar.

To add to the conversation. There is RaceFlight for Revo, Revo Nano and Sparky 2. A Betaflight Port.


larzac 3rd December 2015 - 11:22 am

Hi Oscar

If I was to spend more than $30 for a FC I would not buy an over expensive F3 to run betaflight on.
I would just buy a revo mini for $45 with F4, it’s cheap, it is supported by several FC softwares, it has the power and the hardware for the features++ and it’s already ready for the improvements 2016 will bring.

take off the blinders guys ;-)

Oscar 3rd December 2015 - 12:59 pm

you got a point there my friend :)

Chris 24th November 2015 - 10:03 am

Hi Oscar,

Bookmarked. Excellent write up. Keep up the good work, Sir.

Oscar 24th November 2015 - 6:27 pm

Thank you Chris!

Mike 15th November 2015 - 11:15 pm

Hi Oscar. Is SPR F3 board from BangGood an original one or fake copy? Price seems to be ok but will it run betaflight ??

Oscar 16th November 2015 - 10:00 am

Hi Mike
Sorry I don’t know! I wouldn’t be surprised if it’s a fake copy as these things are not difficult to reverse-engineer and clone… maybe check with Dominic Clifon.
Anyway i think you should get the genuine board to support the designers. :)

Michael 16th November 2015 - 5:20 pm

Hi Oscar

Dominic Clifton is reading your blog and could have a look.
Here is a link. 2 versions available 6 and 10dof called acro and deluxe


Price is reasonable and pictures looks much better than my existing F1 flip32 versions :)

Oscar 17th November 2015 - 10:21 am

Hi Michael,
Dominic told me it’s an unauthorized clone, and they probably use the cheapest possible components so it should be avoided.

Michael 17th November 2015 - 1:11 pm

Hi Oscar

Please put a link to a place where we could buy an original one with some money for Dominic.



Oscar 17th November 2015 - 1:46 pm

it’s widely available, just google it.

Dominic Clifton 11th November 2015 - 2:24 pm

So much dis-information and FUD in the article and replies.

F3 has newer CPU core. Yes it’s 72mhz still but it gets more done and not just because of the FPU.





The F3 also has better I2C handling more is done in hardware. The F3 also has USB bootloader support. F1 requires uart adaptor = more cost.

ThomasS is wrong here. There are many other small differences that make the F3 a better part than the F1.

Oscar 11th November 2015 - 3:50 pm

Hi Dominic,

This article focus on what benefits a F3 processor can bring to a flight controller at the time the article was written (as most people who read this article would be concerned about). I don’t think there was “mis-information” in my post. And thank you for pointing out the advantages of a F3 that I missed however I don’t think they would affect the conclusion of this article.

“The F3 also has better I2C handling more is done in hardware. ”
– what does that mean in terms of flight performance? Sampling rate is still the same anyway.

“The F3 also has USB bootloader support. F1 requires uart adaptor = more cost.”
– And yet your FC is 3 times the price of a Naze32.

I am sorry if this post caused any impact on your sales (although I doubt there would be any), but I hope you can point out what you think is mistaken in more detail so me and anyone who is reading this can learn from it.

Dominic Clifton 15th December 2015 - 11:49 pm

Hi Oscar,

F3 I2C handling is better since the hardware does more meaning less time spent in ISR’s meaning more time for flight code and other code to run. Sampling rate is unrelated.

“However there is no performance gain when doing integer calculations, such as PID controller 1 – Rewrite, which is integer based algorithm.” Not true, there is, time it :D Not sure where you got that information from. We generate Coretex-M4 specific code using the GCC ARM flag ‘-mcpu=cortex-m4’ which generates optimized code for the CPU core.

When products come on the market they are often at a higher price and go lower over time. Just ask apple, microsoft, sony, etc. R&D time has to be paid for somehow and it’s generally by the early adopters who want the latest and greatest. Costs are also reduced as manufacturing processes improve. This happens in many markets, not just FC’s as I’m sure you’re aware.

Keep up the good work on your blog too, some really good posts. Looking forward to reading more!

Jerome Demers 16th October 2015 - 3:14 pm

The SPF3 is expensive because Dominic Clifton wants some direct money for the hardwork he puts in Cleanflight.
Without the help of these guys, those F1, F3 discussion would not even matter.

Tim 14th March 2017 - 4:46 am

Innovation requires incentive. Incentive is usually in the form or monetary gain or the avoidance of undesirable treatment ( Soviet era communist method which is effective but often causes a level of mental stress that stifles novel ingenuity ).
In the pharmaceutical industry, R&D is ridiculously expensive since the process for creating a drug from start to market is a daunting one. Remove the ability to make a profit for doing this advances in pharmaceutical technology cease. Not only do they need to recoup the expense incurred bringing a particular drug to market but also that of the many compounds that failed.
Okay, so you may have an idea what type of work i’m in but you need not have my bias to buy in to what I’m saying. In fact, if you don’t “buy in” then you’re selling out….to companies that operate in places governed by political systems that are un-American if not anti-American. Buy genuine products whether they are medications or flight controllers.

ThomasS 16th October 2015 - 7:49 am

Hi Oscar,

I really like what you write and you have a good blog. You say it is share knowledge and I hope helping share mine from industry, is this ok? I am EE for many years and programmer with much industrial machinery control experience.

The STMF3 is not held in any respect because it does not fit well in commercial applications and is ignore, F3 is old now not new and failed because nothing much offered over F1 for performance. Only people in multis think F3 is new, this is strange.

F3 is same F1 power with math co-pro only, same speed as F1. Math unit is not a big deal, it can help but very small help. Advantage of F3 is inbuilt comparators which we do not need in mutlis so as not needing comparators F3 is bad choice .

Why board also cost so much, F3 max add $2 over F1, yet for F3 hardware over double price of F1 board.

Myself for acro, FPV and racing F1 only, very low cost and betaflight with CC3D is best no need for more.

F4 is needed for doing real navigation. F3 is useless middle ground, I explain. F3 lacks performance for good Kalman filter at good speed, I have Sparky and disapoint, Sparky 2 is as they learn from big F3 mistake use F4 as can run EKF much faster and much more stable, problem is taulabs software is very bad but maybe librepilot support for sparky2 which is better more serious software.

For me very surprising F3 is used by any new board, bad move and maybe they follow sparky without think and make same mistake.

Navigation without good EKF is possible but it will not match EKF base system, everyone should know this.

So you know SPR F3 is very terrible design hardware, I do not say to knock but you must ask anyone that knows and will tell you same, it is true but would not buy F3 FC in 2015, wrong direction.

Sorry to disagree with you, I am friendly towards you but information all should know to avoid hype of poor F3 as it has no real world advantage and very many more cost, over double F1 FC.

Oscar 16th October 2015 - 9:45 am

Hi Thomas,
thanks so much for your input! Your info is really interesting!

I guess the Tornado F3 is still a good buy, which is still under $30.

Oscar 16th October 2015 - 10:09 am

also by the way, i think you should join our facebook group, we will all definitely benefit from your electronics knowledge from time to time :D … http://multicopterFPV.com

sevet 20th October 2015 - 12:14 am

I think the move to F3 was to gain as much performace without the need for a big porting job on the software side, a move to F4 is a big one. also, goodluckbuy is selling the delux SP F3 for 45$

The HW invertors are almost worth it by themselves

mauro 20th October 2015 - 10:42 pm

you said that “optimal loop time” is 1000, this is not true as this depends on what sensor you are using and their real Output Data Rate, witch in many board is limited by the fact that use i2c (900 read/s, 2280read/s with fast i2c) instead of SPI (27593read/s).

About f3 useless… is estimated that CF on a F1 use 48% of time on floating point (see flysherlockair.com/2015/07/how-does-cleanflight-spend-its-time-lets-profile/) and it goes down to 8% on a F3.. this is a great gain to implement better EKF or PID for example.

About good EKF… very hard to do, and very hard to test qualitatively against a DCM. I’ve done some test and DCM run a bit higher than max ODR of many sensor (6KHz) on F1; i think lower integration give better result than a EKF, and this seems right from who is trying it (i think part of boris improvement are given by DCM, see github.com/cleanflight/cleanflight/issues/1253 and github.com/cleanflight/cleanflight/pull/1404)

For sure would be nice to jump to F4 or even better a F7, maybe th package with a lot of pin, flash and ram

Oscar 16th November 2015 - 11:20 am

1000 is optimal at the moment if you read the betaflight thread more carefully. even you can do it faster with SPI gyro, it’s not the most stable and need a lot more testing and tweaking, Boris suggested to run 1000 looptime for now.

p25o1 16th October 2015 - 7:38 am

is the naze rev 6 f3 ?
and is there a F4 base/beta flight for revo/sparky v2

sparky would be interesting since it also has an integrated flash storage on board for blackbox

Oscar 16th October 2015 - 9:38 am

no, it’s a f1.
I am not quite sure myself, maybe have a search on the betaflight thread.

Andrew 17th October 2015 - 9:10 am

Yes there is but it is maintained by someone else. github.com/sambas/cleanflight

MikeF 16th October 2015 - 12:29 am

Which would you choose between the SP3 and the Dodo. Seems like they are very similar, but there has to be some differences. (other than price)

ThomasS 16th October 2015 - 8:02 am

Is same feature, dodo is clone of SRP but dodo use professional board design and fix all layout issue.

F3 board no good, stick to F1 with cleanflight and betaflight still many ram left on F1 for acro flight.

MikeF 16th October 2015 - 12:51 pm

Are you saying the SP3 and the Dodo are no good and it’s best to stay with an F1 board?

theledman 16th October 2015 - 9:47 pm

HI Thomas

I think he just means that F3 boards aren’t worth the premium in price.

The SP3 board has layout issues but seems to perform well enough that people like FGA think they’re fine to fly with. I know MrSteele flies with the Dodo but he admits he sticks with cleanflight 1.9 and controller 1. The only issue i’d see with using the SP3 is that it’s a double sided board which means there are SMT components on the bottom. Means you have less real estate to throw a polulu under it like you can with a naze or single sided board.

With that said, a TornadoF3 is roughly the price of a Naze and gets you an additional UART plus native SBUS support.

Ultimately it depends on what you need. If you only need 1 UART (in addition to USB), you’ll be fine with an F1 board like oscar says.