Skystars F411 + KO25 BLHeli_S Fly Stack (20x20)

The Skystars F411 and KO25 BLHeli_S stack provides a complete control and power solution in a highly compact footprint. Designed for compact freestyle builds and sub-250g micro quads, this stack pairs an STM32F411 flight controller with a 25A 4-in-1 ESC. The FC has a clean layout with easily accessible solder pads to simplify wiring in tight canopies, while the BLHeli_S ESC ensures smooth commutation for small, high-KV motors.

Key features

• Compact 20x20mm mounting layout designed for tight micro and toothpick frames
• 25A continuous output with a 45A peak rating to handle aggressive throttle punches
• Built-in 5V/2A BEC to reliably power your receiver, camera and video transmitter
• Native BLHeli_S ESC firmware with full compatibility for Bluejay flashes

Specifications

• FC MCU: STM32F411
• Gyro: BMI270
• OSD chip: AT7456E
• UARTs: 2 hardware (UART1, UART2) plus 1 software (UART3)
• Receiver support: CRSF, SBUS, IBUS, DSM
• Barometer: none
• Blackbox: 16MB
• Input voltage: 3-6S LiPo
• ESC continuous current: 25A
• ESC peak current: 45A
• ESC firmware: BLHeli_S, DShot300/600
• BEC output: 5V 2A
• Mounting pattern: 20x20mm (M2)
• ESC size: 31 x 30 x 6.9 mm
• Weight: FC 4.3 g, ESC 5.4 g
• Supported firmware: Betaflight

Pre-flashed with BLHeli_S, the KO25 ESC supports standard DShot protocols out of the box. For pilots wanting maximum flight time and motor smoothness, the ESC can be flashed to Bluejay to enable bidirectional DShot and RPM filtering.