Recommend Battery:

GNB 1100Mah 4S 15.2V 60C/120C Lihv Lipo Battery with XT30 Plug

GAONENG GNB LiHV 4S 15.2V 850mAh 120C XT30 LiPo Battery

Happymodel Crux35 / Crux35 HD / Crux35 HDZero FPV Drone

NOTICE: SPI ELRS version (Crux35/HD/HDZero) has been discontinued. The new ELRS V2 version features the CrazyF411 ELRS AIO flight controller with UART ExpressLRS receiver.

NOTICE: Loctite 222 is used on motor screws. Please take care when disassembling motors.

Overview

The Crux35 Series is an ultra-lightweight 3.5-inch BNF FPV freestyle drone built for performance. Weighing only 87g (analog) or 108g (digital), it delivers incredible thrust-to-weight ratio and freestyle capabilities. Powered by the EX1404 motors and HQProp tri-blade props, Crux35 offers a smooth and responsive flying experience. Ideal for freestyle, cinematic flying, or even racing.

Versions Available

• Crux35 (Analog) with Caddx Ant camera and OVX303 VTX
• Crux35 HD with Caddx Nebula + Vista Kit
• Crux35 HDZero with HDZero Whoop VTX + RunCam HDZero Camera

Receiver Options

• UART ExpressLRS 2.4GHz (V3.0.1, CRSF protocol)
• SPI FrSky D8/D16, S-FHSS compatible

Main Features

• Ultra-lightweight 3.5-inch freestyle drone
• Supports HD, HDZero, and analog video transmission
• High-efficiency EX1404 3500KV motor
• Compatible with Naked GoPro or SMO 4K
• Recommended battery: 4S 750mAh (max: 4S 1100mAh)

Specifications

• Wheelbase: 150mm
• Weight: 87g (Analog), 108g (HD)
• Size: 130x130x45mm (without propellers)
• Flight Time: 9–15 min (4S 750mAh)

Flight Controller Options

CrazybeeF411 ELRS (UART ELRS Version)

• MCU: STM32F411CEU6
• Gyro: ICM42688P or BMI270
• ESC: 20A 4-in-1 BLHeli_S
• BEC: 5V 1.5A
• Target: CRAZYBEEF4DX

ELRS X1 (Discontinued)

• MCU: STM32F411CEU6
• Gyro: MPU6000
• ESC: 12A 4-in-1 BLHeli_S
• Target: CRAZYBEEF4SX1280

CrazybeeF411 FrSky (SPI)

• MCU: STM32F411CEU6
• ESC: 20A 4-in-1 BLHeli_S
• Target: MATEKF411RX

Motors

• Model: EX1404 KV3500
• Configuration: 9N12P
• Stator: 14x4mm
• Weight: 9g

Propellers

• Model: HQProp T3.5X2X3
• Size: 3.5 inch, 3-blade
• Material: Polycarbonate

Video Systems

HD Version – Nebula Nano Kit

• Resolution: 720p60, latency 32ms
• Transmission Power: up to 700mW
• Range: Up to 4km

HDZero Version

• Camera: RunCam Nano HDZero
• VTX: HDZero Whoop
• Resolution: 1280x720@60fps

Analog Version

• Camera: Caddx Ant (1200TVL)
• VTX: OVX303 or OVX306 (0/25/100/300mW)

What’s in the Package

• Crux35 Frame
• CrazyF411 ELRS / FrSky / ELRS X1 Flight Controller
• Motors: 4x EX1404 KV3500
• Propellers: 4x CW + 4x CCW
• FPV System (depends on version)
• Screwdriver, battery strap

Recommended Battery

• 4S 750mAh (Best Performance)
• Max Supported: 4S 1100mAh

Note: Ensure correct VTX power settings for your region. Always verify Betaflight and ExpressLRS configurations before flight.

Firmware Hex file  (Betaflight official 4.3.1):

Betaflight_4.3.1_STM32F411

Dump file:

Betaflight 4.3.1 dump for Crux35 analog ELRS V2

Betaflight 4.4.2 dump file for Crux35 analog ELRS V2

If your Crux35 has high throttle oscillations, you can upgrade the flight controller firmware to 4.4.2 and then use this dump file to fix the problem.

Betaflight 4.3.1 dump for Crux35 HDZERO and HD DJI ELRS V2

Manual:

Crux35 Crux35HD DJI and Crux35 HDZERO FPV Racer Drone ELRS V2 manual

Bind procedure video: