Holybro Kakute F4 AIO V2 is one of the latest flight controllers from Holybro. This flight controller is intended to be used with four separate ESCs. It features InvenSense ICM20689 gyro, integrated power distribution board, current sensor and on-screen display. I wanted to try a build with 32 kHz Gyro update frequency along with a BlHeli_32 ESCs and the Holybro Kakute F4 AIO V2 with Tekko32 ESCs ticked all boxes, so I have decided to give it a try. I’m writing this review after two months of active everyday use on what has become my favorite build.
If you are new to the flight controllers and want to learn more, consider visiting our “All About Multirotor Drone FPV Flight Controllers” article.
- STM32 F4 flight controller processor
- InvenSense ICM20689 high sensitivity foam suspended gyro 32 kHz
- USB VCP Driver, you can use all UARTs simultaneously
- 5 hardware UART ports
- Serial receiver support (SBUS, iBus, Spektrum, Crossfire). This board will not work with PPM and PWM receivers
- BMP280 barometer
- 128 Mbit Dataflash chip for Blackbox logging
- Dimensions: 35x43x7mm and 30.5mm standard mounting holes
- Weight: 7 grams
- Price: $40.99 GetFPV
Initial Thoughts on the Kakute F4 AIO V2 Flight Controller
The flight controller comes in the already recognizable Holybro plastic box encased in foam padding. The box includes the flight controller and two spare IMU mounting foams. The board layout is simple and clean and it enables you to easily solder the ESCs, receiver, FPV camera and video transmitter.
You can find the battery leads on the back of the board while the ESC pads are laid out on the front and the back of the board. If you want to have the battery connector on the side of the frame then you will have to use longer wires. The USB connector is on the right side.
The Kakute F4 AIO V2 clean layout enables you to easily solder the ESCs, receiver, FPV camera, and video transmitter, in addition, all solder pads are through-hole that enables more secure solder joints, especially for beginners.
The high-performance InvenSense ICM20689 gyro is almost in the center of the flight controller and it. It is a separate board that connects with the flight controller through a flat cable. The gyro is suspended on special vibration canceling foam, therefore preventing the unwanted vibrations from reaching the gyro. There is no need to soft mount the flight controller.
Since this is an AIO board and it has a build in PDB it also includes pretty accurate voltage and current sensors. You are able to use up to 6S batteries and pull 120 Amps of maximum continuous current.
The Kakute F4 AIO V2 features ESC telemetry on UART5 (Rx5) and the ESC telemetry pads are located near each ESC signal pad. The telemetry feature is available if you are using BlHeli_32 or Kiss ESCs. By enabling this feature you will be able to observe ESC temperature, motor rpm and ESC current usage through the on-screen display.
The flight controller also includes BMP280 barometer for approximate height measurement.
Wiring the Kakute F4 AIO V2 Flight Controller
The wiring process was straightforward. There are clear labels next to each pad and in addition, there is a PDF manual written by Joshua Bardwell.
In case you are wondering about the meaning of some labels, here is a pin-out diagram:
I wanted to give this flight controller a fair review so I have put it into a complete new build. I’m using a Armattan Mongoose frame, Emax RS2306 2400KV motors and Tekko32 ESCs.
First I have soldered the battery leads on the “+” and “-” pads correspondingly. Then I have soldered the ESCs on the designated “B+” and “G” pads on the edges of the board. After that I have soldered the wires to the X4R receiver, using the R3, 5V, GND and SP pads on the left side of the board.
I have powered the VTX from the B+ pad on the top left side and used the 5V next to it to power the FPV camera, next I have used the VO and VI pads below them to connect the video in and video out signals correspondingly. In the end, I have connected the smart audio wire from my VTX on T6 and finally the buzzer to the BUZ- and 5V.
Betaflight / Butterflight configuration
At the moment I’m running this board on Butterflight 3.5 and it has been on Butterflight from day one. It is capable of 32 kHz gyro update frequency and 16 kHz PID loop frequency while running around 53% CPU load when idle.
The board comes with preconfigured Betaflight. Under the Ports tab, the UART 1 is used for telemetry, UART 3 has the Serial RX enabled and it is used for connecting your receiver, UART 4 is set up for controlling peripherals such as RunCam Split and UART 6 is used for smart audio.
I needed to set my receiver mode and serial receiver provider to match my FrSky X4R receiver. Then I have configured the “Modes” tab to match my switch configuration.
Post Testing Thoughts
I have been flying this build for two months and by now it has become my favorite FPV quadcopter. I haven’t encountered any kind of problems taken into consideration that I’m running it on Butterflight.
For this build, I am using Tekko 32 (Wraith 32) ESCs which are considered one of the best BlHeli_32 ESCs that are available on the market today. I do have set the ESC PWM frequency to 48kHz and the throttle changes are smooth as silk 😉
There is a little bit more soldering involved considering that you will have to solder each individual ESC and on top of that you have to solder one additional ESC telemetry wire but all this work is well worth it.
The soldering pads layout is spot on and each pad is labeled clearly. It is very easy to wire up and mount this flight controller. When mounting it, take care that there is enough clearance between the ribbon cable that is connecting the gyro board and the other components in the stack. I have seen cases of Kakute gyro strange behavior because of this issue.
As for the flight performance, this flight controller is working flawlessly so far, I have had few good crashes and even had some flights with bent and chipped propellers and this thing is performing as if nothing ever happened.
The video feed is clear without any visible noise. In some cases, on sharp maneuvers, few black lines may appear. This is a sign of a power-hungry VTx or the 5v regulator not getting enough power to the camera. I have yet to try and power the VTx directly from the battery leads and then the camera directly from the VTx.
If you are planning on buying a flight controller that has a gyro capable of 32 kHz gyro update frequency that doesn’t need soft-mounting and also you would rather have four separate ESCs than a 4in1, then I would highly recommend the Kakute F4 AIO V2 Flight Controller.
In addition, this is a very good solution if you want a build with a low profile frame. It has an integrated PDB and you will only need to properly place the VTx and the receiver.