With the release of the new DJI O3 Air Unit, everyone started to look for a compatible flight controller. The SkyStars-RC F722HD Pro has impressive specs and a dedicated digital VTX connector. SkyStars offers the F722 MINI HD Pro in a bundle with three types of ESC boards, 40A, 45A, and 55A -shown in this review.
In a nutshell, a flight controller is the drone’s brain and uses the data gathered by various sensors and the pilot’s input to calculate the desired speed for each of the four motors. The FC sends the desired speed signal to the Electronic Speed Controllers (ESCs) that power and control the motors. In addition to the basic sensors such as Gyro (Gyroscopes) and Acc (Accelerometer), the F722 HD Pro also has a Barometer (air pressure sensor). The FC is also a hub for other peripherals, such as Radio Receiver, GPS, Sonar sensor, LED, Buzzer, etc.
SKYSTARS F722HD Pro runs on Betaflight, an open-source software developed and maintained by the community. This fork differs from Baseflight and Cleanflight, focusing on flight performance, leading-edge feature additions, and broad hardware support.
SKYSTARS F722HD Pro + KM55A ESC FlyStack review
Disclosure: I received this flight stack as part of a product review collaboration with SkyStars-RC. Although the electronics were offered for free, all opinions in this article remain my own, and the sponsor in no way influenced me.
SKYSTARS Tech Co was established in 2016 and is focused on high-quality R/C model products and accessories. Their product range covers RTF drones and main parts such as frames, flight controllers, ESCs, motors, radio receivers, and more. There is no pinout and wiring diagram included, so you need to look for it online.
With the F722HD Pro + KM55A ESC flight stack, SkyStars also sends me a set of KOKO 2207 1950KV motors and a Bolt5 200mm 5 Inch FPV T700 carbon frame kit. In a few weeks, I will also publish a build tutorial article with these parts.
At a glance
The flight stack is packed in a nice cylinder-shaped plastic container. In addition to the two electronic boards, there is included pretty much everything you need to install in an FPV drone. Despite that, the FC and ESC are already stacked using soft mounts and wired correspondingly, SkyStars-RC includes a second FC-to-ESC ribbon cable, more silicone anti-vibration rings, and a set of longer stacking screws. The box also contains an XT60 battery plug, a battery cable (2x10cm), a 35v/650μF LOW ESR capacitor, and a DJI O3 Air Unit cable.
While the F722 Mini HD Pro flight controller measures 35x28x7mm, the KM55A ESC board is 35*47*6.5mm. Both have standard 20x20mm/M3 mounting patterns. Together weights about 20-22 grams.
F722Mini HD Pro flight controller
The Mini F7HD Pro board is based on an STM32F722RGT6 high-speed 32bit Arm Cortex CPU, AT7456E OSD chip, and a 16M black-box flash memory. The FC is 3-6S Lipo compatible, but remember that the original DJI AU can be powered only up to 4S (16.8V) LIPOs.
The F722 Mini HD Pro has many input/output pins, but unfortunately, all are unlabeled. At least the soldering pads have a decent size, so it would not require a microscope when you made the wiring. It is compatible with both analog and digital FPV systems. The DJI Air Unit connector is doubled with soldering pads. There are also additional pads for Caddx Vista\RunCam Link VTX.
On each corner of the board, there is a LED pin. Near the boot micro push-button, there are the buzzer pins. The F722 Mini HD Pro has a Type-C configuration and firmware upgrade port.
Caution: The Air Unit connector is reversed on the flight controller. You must use the included cable! Using the original O3 cable, it will connect 10v to the SBUS port. Also, remember, if you want to use an external radio receiver on RX1, do not connect the HDL pin to SBUS.
KM55A Turbo 2020 32Bit 4-in-1 ESC
Electronic speed controllers (ESCs) are electronic devices that allow drone flight controllers to control and adjust the speed of the brushless motors. In the past, they were big and individual for each motor. These days, 4-in-1 ESC boards are commonly used. The SKYSTARS KM55A can deliver continuously up to 55A or peeks (≥ 10S) of 70A per channel. To cover this high power consumption, your battery should be able to deliver 220-280A.
The KM55A board has a large motor (2×6) and battery soldering tabs. There are drilled solder pins for the LOW ESR capacitor. If you prefer soldered wires instead connectors, there are dedicated pads for this as well.
Communication between FC and ESC uses Dshot (Digital shot) protocol resistant to electrical noise and jitter, as each pulse represents one binary digit (bit). SKYSTARS-RC’s KM55A ESC is compatible with the latest protocol versions, Dshot 600 and 1200.
Pricing and availability
As I mentioned in the introduction part of my review, the F722HD Pro flight controller is available with three types of ESC boards (40A, 45A, and 55A), all having the price of $99.00 at the manufactures website. If you prefer wireless configuration, SkyStar also has the F722 WIFI HD3 board with large soldering pads and dedicated ELRS receiver row pin straight mounting.
|SkyStars F722 Mini HDpro Flight Controller|
|OSD||Betaflight OSD & DJI HD OSD (UART6)|
|UART||6 hardware UARTS (UART1,2,3,4,5,6)|
|BEC||5V 2A & 10V 2A|
|Input Voltage||3-6S LiPo|
|Firmware||Custom BetaFlight (SKYSTARS F7HDPro)|
|SkyStars KM55A 32Bit 4in1 55A ESC|
|Peak Current||70A for less than 10s|
|Mounting holes||20X20 mm/M3|