BETAFPV Air Brushless Flight Controller 1S STM32G473 ICM42688P 4IN1/5IN1 5.8GHz VTX

Overview

The BETAFPV Air Brushless Flight Controller is a 1S flight controller designed for ultralight whoop builds, available in 4IN1 and 5IN1 versions. It uses the STM32G473CEU6 processor (168MHz) and an ICM42688P (SPI) 6-axis IMU, and it integrates an onboard 5.8GHz VTX (25-400mW, plus PIT) to reduce wiring and weight.

Key Features

• Ultra-thin board: 0.8mm
• Weight: 2.9g (4IN1) / 3.6g (5IN1)
• Versions: 4IN1 (FC+ESC+OSD+VTX) or 5IN1 (FC+ESC+OSD+VTX+RX)
• Onboard VTX: 5.8GHz 48 channels, SmartAudio 2.0, 25/100/200/400/PIT
• Built-in ESC: 5A continuous, supports D-shot300 and D-shot600
• Blackbox memory: up to 16MB
• Voltage & current sensor
• 5V BEC: 5V 3A (output current decreases as temperature increases)
• Extra serial port resources: UART2 is connected to VTX by default; 3 full-featured serial ports are reserved for external CRSF/SBUS receivers, GPS, HD VTX, or other serial devices
• 5IN1 version includes Serial ELRS 2.4G RX (V3.4.3), using CRSF protocol

Specifications

Flight Controller (FC)

ESC

VTX

VTX Output Power Test Data (25mW Setting)

• Calibrated measurement condition: more than 60 seconds after powering on the flight controller
• At 25mW setting: 14dBm ±0.8dBm (21mW to 30mW)

• The 4IN1 Air FC V1.1 version has already solved the VTX output power anomaly problem.

Setup Notes

• VTX power: higher VTX power consumes more energy and generates more heat, reducing flight time. For indoor use, 25~100mW is recommended.
• Motor wiring: only soldering is supported. Keep soldering iron temperature below 370°C and limit soldering duration to 1~2 seconds.
• VTX antenna: install the 5.8G VTX antenna before powering on the flight controller; alternatively set transmission power to 0 to avoid burnout.

Serial ELRS 2.4G RX (5IN1 Version)

The integrated Serial ELRS 2.4G RX communicates using CRSF protocol. Binding method:

• Power on/off the flight controller three times.
• RX LED quick double-blink indicates bind mode.
• Put the RF TX module / radio transmitter into bind mode.
• Solid RX LED indicates bound.

The Serial ELRS 2.4G RX can be updated via Wi-Fi or Betaflight serial passthrough. Passthrough notes provided:

• Connect FC to computer, but do not connect to Betaflight Configurator.
• Choose target: BETAFPV 2.4GHz AIO RX.
• Flash using the Betaflight Passthrough option in ExpressLRS Configurator.

Firmware

• FC firmware: Betaflight_4.5.0_BETAFPVG473
• Betaflight release reference: https://github.com/betaflight/betaflight/releases/tag/4.5.0
• Firmware and CLI dump: https://support.betafpv.com/hc/en-us/articles/33840464515353-Firmware-for-Air-FC-G4-V1

Bluejay ESC Firmware Notes

• BB51 ESC solution reference: A_X_5_96KHz_V0.19.hex for BB51 Bluejay hardware
• Do not flash the firmware with a shorter interval; otherwise there is a chance of stalling and burning the flight controller.
• Referenced tools and pages:
  • ESC-Configurator: https://preview.esc-configurator.com/
  • Bluejay project: https://github.com/bird-sanctuary/bluejay
  • Bluejay releases: https://github.com/bird-sanctuary/bluejay/releases
  • BLHeliSuite16714903: https://github.com/4712/BLHeliSuite/releases/tag/16714903
• Additional Bluejay .hex filenames shown: A_X_5_48_v0.19.2.hex, A_X_5_96_v0.19.2.hex, A_X_70_24_v0.19.2.hex

Connecting External RX/VTX (Ports Guidance)

• Analog VTX: set UART2 peripherals as VTX (TBS SmartAudio).
• Receiver: configure UART3 as Serial RX.
• Receiver protocol examples shown:
  • SBUS Protocol RX: Frsky XM+ / Futaba AC900 / Flysky RX2A Pro
  • CRSF Protocol RX: TBS Nano / ELRS Series RX

Recommended Parts

• Drones: Air65, Air75
• Frames: Air65, Air75, Meteor65, Meteor65 Pro, Meteor75 Pro
• Motors: 0702/0702SE, 0802/0802SE, 1102
• Receiver (for 4IN1 or external RX use): ELRS Lite Receiver, ELRS Nano Receiver

What’s Included

• 1 x Air Brushless Flight Controller
• 1 x 2.4G antenna (only 5IN1 version)
• 1 x Type-C to SH1.0 adapter
• 1 x SH1.0 4Pin adapter cable
• 1 x 5.8G VTX antenna
• 1 x BT2.0 U Whoop Cable Pigtail (40mm)
• 4 x M1.4*4 self-tapping screws
• 4 x shock absorbing ball

For wiring, configuration, or firmware support, contact https://rcdrone.top/ or email support@rcdrone.top.

Details

Built for ultralight 1S whoop setups, the Air Brushless FC combines core flight electronics with an onboard 5.8GHz VTX to keep wiring and weight down.

Real output at 25mW varies by channel and stabilizes after warm-up, helping set realistic expectations for indoor power levels.

Compact pad placement keeps the stack tidy, but benefits from fine-tip soldering and careful wire routing.

Key hardware highlights include the STM32G473 processor, SPI IMU, integrated VTX, and ESC support for high-rate protocols.

The top-side layout groups camera input, serial pads, and the VTX antenna connection for cleaner whoop builds.

Bottom-side pads provide ESC outputs, USB wiring points, and additional connections for OSD and LED features.

The 5IN1 version adds onboard receiver connections, reducing extra components and simplifying wiring on micro frames.

Extra UART access and boot pads make it easier to expand with peripherals while keeping the main build lightweight.

Processor benchmark data helps compare MCU overhead when running modern Betaflight features on small builds.

Choose 4IN1 for external receiver flexibility, or 5IN1 for maximum integration with FC, ESC, OSD, VTX, and RX onboard.

Standard 4IN1 wiring supports common receiver types via UART, with camera connections kept on dedicated pads.

Optional accessories like a buzzer and LEDs can be added while keeping UART resources available for additional gear.

Betaflight port settings determine whether a UART is used for SmartAudio control or receiver input such as SBUS or CRSF.

Included hardware and cables help get the build started quickly, with mounting accessories to suit micro frames.