1. Introduction
The Radiomaster NEXUS-X and NEXUS-XR are advanced helicopter flight controllers designed for optimal performance with Rotorflight 2.2. These controllers offer precise control, seamless stabilization, and robust flight performance for RC helicopters. The NEXUS-X is a standalone flight controller, while the NEXUS-XR integrates a 2.4GHz ExpressLRS receiver for enhanced connectivity and simplified setup.
Both models feature a powerful STM32F722 MCU, a highly accurate ICM42688P 6-axis MEMS motion tracker, and a built-in 256MB Black Box for flight logging and tuning. They are housed in a durable CNC-machined aluminum case that provides both protection and efficient heat dissipation.
2. Package Contents
Verify that all items are present in your package:
- 1 * NEXUS-X or NEXUS-XR Helicopter Flight Controller
- 3 * JST-GH 4 Wire pigtail cables
- 1 * JST-GH to Servo Plug (dupont 3 pin connector)
- 1 * Ultra light-weight and flexible USB-C extender
- 1 * Type C extension cable
- 1 * JST-ZH1.5 "DSM" Telemetry cable (Note: Telemetry only, does not support DSM Receivers)
- 1 * Voltage telemetry wire
- 3 * 3M double-sided mounting tape
- 2 * Heat shrink tubing
- 1 * Inventory Card
3. Setup
3.1 Physical Installation
The NEXUS-X/XR features a compact and lightweight design, making it suitable for various helicopter builds. Use the provided 3M double-sided mounting tape to securely attach the flight controller to your helicopter frame. Ensure the orientation is correct as per your Rotorflight software configuration.
3.2 Wiring Diagrams
Carefully follow the wiring diagrams below for connecting your servos, ESC, RPM sensor, telemetry, and receiver. The flight controller supports both 760μs and 1520μs tail servos up to 12V, and is compatible with tail motors.
NEXUS-X Wiring Diagram
NEXUS-XR Wiring Diagram
3.3 Receiver Connectivity
The NEXUS-X supports various external receivers including CRSF, ELRS, GHOST, S.BUS, SUMD, IBUS, XBUS, EXBUS, PPM, and MSP via its multi-function UART ports. It also supports Plug’n’Play solder-free RP3-H ELRS receivers.
The NEXUS-XR features an integrated 2.4GHz ExpressLRS receiver with dual Semtech SX1281 transceivers, eliminating the need for an external receiver. This provides superior RF performance and simplifies wiring.
3.4 Power Supply
Both models support a wide external voltage input range of 3.6V to 70V. The internal BEC provides stable and reliable power delivery to electronics. Dedicated isolated power supplies (1.8V for gyro, 3.3V for MCU, and 5V for interfaces) minimize noise for optimal performance.
4. Operating Instructions
4.1 Rotorflight 2.2
The NEXUS-X and NEXUS-XR are optimized for Rotorflight 2.2 firmware. Ensure you have the latest Rotorflight firmware installed for the best performance and compatibility. Refer to the official Rotorflight documentation for detailed software configuration and tuning guides.
4.2 Flight Control and Stabilization
The STM32F722 MCU and ICM42688P 6-axis MEMS provide precise control and seamless stabilization. This combination offers excellent vibration resistance and enhanced signal rejection, crucial for both electric and nitro helicopters.
4.3 Servo and ESC Compatibility
The flight controller supports both 760μs and 1520μs tail servos up to 12V. It is also compatible with various ESC types including PWM, Oneshot, Multishot, and Dshot.
4.4 Rotorflight Rescue
The Rotorflight Rescue feature is a standard safety function designed to assist in emergencies. Configure this feature within the Rotorflight software according to your preferences and helicopter setup.
4.5 Telemetry and Data Logging
Telemetry support includes S.BUS, HoTT, S.Port, MSP, EDGETX, and ELRS. The 256MB onboard flash memory (Black Box) allows for extensive flight logging, which is invaluable for post-flight analysis and tuning.
For NEXUS-XR, WiFi updates are supported, allowing for convenient firmware updates and configuration changes.
5. Maintenance
5.1 Case Protection and Cooling
The CNC-machined aluminum case not only provides robust protection for the internal electronics but also acts as an efficient heat sink, keeping the system cool during demanding flight conditions. Regularly inspect the case for any signs of damage.
5.2 General Care
- Keep the flight controller clean and free from dust, dirt, and moisture.
- Avoid exposing the device to extreme temperatures or direct sunlight for prolonged periods.
- Ensure all connections are secure before each flight.
6. Troubleshooting
If you encounter issues with your flight controller, consider the following steps:
- Check all connections: Ensure all wires are securely connected to the correct ports as per the wiring diagrams.
- Review Rotorflight configuration: Incorrect software settings are a common cause of flight issues. Double-check your configuration in the Rotorflight software.
- Analyze Black Box logs: Utilize the 256MB Black Box memory to record flight data. Analyzing these logs can help identify the root cause of unexpected behavior.
- Firmware update: Ensure your flight controller is running the latest stable Rotorflight 2.2 firmware. For NEXUS-XR, WiFi updates can be used.
- Power supply: Verify that the flight controller is receiving stable power within the specified voltage range (3.6V-70V).
For more detailed troubleshooting, refer to the official Rotorflight documentation or the Radiomaster support resources.
7. Specifications
NEXUS-X Helicopter Flight Controller
| Item | Specification |
|---|---|
| Firmware | Rotorflight 2.2 |
| MCU | STM32F722RET6 |
| Gyro (IMU) | ICM42688P |
| Flash Memory (Black Box. IC) | 256MB (W25N02KVZEIR) |
| Barometer | SPL06-001 |
| Uart | 5 - S.BUS[UART1], TELEM[UART2],PORT-A[UART4], PORT-B[UART6], PORT-C[UART3] |
| Servo | S1, S2, S3, TAIL Servos (Up to 12V ) |
| Rpm Sensor | 1 - FROM ESC FREQUENCY SENSOR |
| AUX | 1 |
| Ext voltage input (tele) | 3.6-70v |
| Receiver Support | CRSF, ELRS, GHOST, S.BUS, SUMD, IBUS, XBUS, EXBUS, PPM, MSP |
| Voltage Supply(DC) | 5 - 16V |
| A-B-C Serial Port Power Output | 5V - 1.5A |
| Telemetry | S.BUS, HoTT, S.Port, MSP, EDGETX, ELRS |
| ESC | PWM, Oneshot, Multishot, Dshot |
| Support Tail ESC | 760μs/1520μs Servo |
| Support Tail Motor | Yes |
| Dimensions | 44.70 x 26.50 x 12.30mm |
| Weight | 20.6g |
NEXUS-XR Helicopter Flight Controller
| Item | Specification |
|---|---|
| Firmware | Rotorflight 2.2 |
| MCU | STM32F722RET6 |
| Gyro (IMU) | ICM42688P |
| Flash Memory (Black Box. IC) | 256MB (W25N02KVZEIR) |
| Barometer | SPL06-001 |
| Uart | 5 - S.BUS[UART1], TELEM[UART2], PORT-A[UART4], PORT-B[UART6], PORT-C[UART3] |
| Servo | S1, S2, S3, TAIL Servos (Up to 12V ) |
| Rpm Sensor | 1 - FROM ESC FREQUENCY SENSOR |
| AUX | 1 |
| Ext voltage input (tele) | 3.6-70v |
| Receiver Support | CRSF, ELRS, GHOST, S.BUS, SUMD, IBUS, XBUS, EXBUS, PPM, MSP |
| Voltage Supply(DC) | 5 - 16V |
| A-B-C Serial Port Power Output | 5V - 1.5A |
| Telemetry | S.BUS, HoTT, S.Port, MSP, EDGETX, ELRS |
| ESC | PWM, Oneshot, Multishot, Dshot |
| Support Tail ESC | 760μs / 1520μs Servo |
| Support Tail Motor | Yes |
| Internal Receiver | RP4TD-M ExpressLRS 2.4GHz Mini True Diversity Receiver |
| Receiver MCU | ESP32 |
| Receiver Type | ISM |
| RF Chip | SX1281 x 2 |
| Antenna | 65mm 2.4GHz Wire Antenna x 2 |
| Frequency Range | 2.4GHz |
| Maximum Refresh Rate | 500Hz / F1000Hz |
| Telemetry RF Power | Max 2 x 10mW |
| Wifi Updates | Yes |
| FW Target | RadioMaster RP4TD-M 2400 RX |
| Bus interface | CRSF |
| Dimensions | 44.70 x 26.50 x 14.30mm |
| Weight | 24.1g |
8. User Tips
- The device performs excellently, providing a high-quality flight experience.
- It has been reported to work very well when mounted on 600mm helicopters.
9. Warranty and Support
For official manuals, firmware updates, and further support, please refer to the official Radiomaster resources. You can often find QR codes on the product packaging that link directly to these resources.
Radiomaster also maintains a presence on social media platforms like Instagram and Facebook, which can be useful for community support and updates.