Skystars F4 HD2 + KO55 3–6S BLHeli_S 4-in-1 ESC 30×30 Stack

The Skystars F4 HD2 + KO55 stack pairs an F405-based flight controller with a 55A BLHeli_S 4-in-1 ESC in a 30.5x30.5mm stack, built for 5-inch freestyle, racing and long-range quads running 3-6S LiPo.

Key features

• STM32F405 flight controller with an MPU6000 gyro, AT7456E OSD chip and 8MB onboard blackbox for post-flight analysis.
• Six full hardware UARTs handle GPS, receiver, telemetry and a digital HD air unit without port-sharing.
• KO55 ESC delivers 55A continuous current per channel, with a current sensor for live telemetry.
• BLHeli_S firmware supports DShot300/DShot600 for responsive motor control.
• Silicone grommets, an XT60 power lead and interconnecting harnesses are included for a clean build.

Specifications

• FC processor: STM32F405
• Gyro: MPU6000
• Barometer: yes
• OSD chip: AT7456E
• Blackbox: 8MB onboard flash
• BEC output: 5V/3A
• Hardware UARTs: 6
• LED strip and beeper pads: yes
• ESC continuous current: 55A
• ESC firmware: BLHeli_S (BB21 MCU)
• Supported firmware: Betaflight, INAV
• Mounting pattern: 30.5x30.5mm, 3mm hole
• FC size: 36 x 36 mm, 6 g
• ESC size: 41 x 46 mm, 13.3 g

The standard 30.5x30.5mm mounting pattern fits most mid-size freestyle and long-range frames, and the included hardware keeps wiring tidy on installation.