FPV Racing Drone Build¶
Project Overview¶
Building a 5-inch FPV racing quad from scratch. This build focuses on a lightweight, durable frame with digital HD video using the DJI O3 Air Unit. Total dry weight target: under 350g.
Parts List¶
| Component | Model | Weight |
|---|---|---|
| Frame | TBS Source One V5 | 115g |
| FC + ESC Stack | SpeedyBee F405 V4 / 55A | 35g |
| Motors | EMAX Eco II 2207 1700KV | 4 x 32g |
| FPV System | DJI O3 Air Unit | 36g |
| Receiver | ExpressLRS EP2 | 2g |
| Battery | 6S 1300mAh LiPo | 215g |
| Props | Gemfan 51466 V2 | 4 x 8g |
Build Process¶
Frame Assembly¶
The Source One V5 is an open-source frame design with excellent parts availability. The true-X geometry provides predictable handling. I used blue Loctite on all frame screws — vibrations will work them loose otherwise.
Electronics Stack¶
The FC is flashed with Betaflight 4.4. Key configuration:
# Betaflight CLI Dump (abridged)
set motor_pwm_protocol = DSHOT600
set dyn_notch_count = 3
set dyn_notch_q = 300
set simplified_master_multiplier = 120
set osd_rssi_pos = 2080
set osd_battery_voltage_pos = 2112
Tuning¶
The default Betaflight 4.4 RPM filtering works remarkably well on this build. I only needed to adjust:
- PID gains: Slight increase on pitch P and D for tighter flips
- RC smoothing: Auto mode with derivative filter
- Throttle curve: Mild expo for smoother cruising
Motor Direction
Running "props-out" rotation (reversed default) provides slightly better stability in tight corners at the cost of some raw top speed.
Flight Characteristics¶
- Top speed: ~140 km/h
- Flight time: 4-5 minutes aggressive, 6-7 minutes cruising
- Range: 1.5 km+ with ExpressLRS at 250mW
DJI O3 Impressions¶
The O3 Air Unit provides stunning HD video with extremely low latency. The 155-degree wide-angle lens on the camera is perfect for proximity flying. Recording at 4K/60fps produces great cinematic footage even from a race quad.
What's Next¶
- Tune a 3-inch cinewhoop build for indoor flying
- Set up a GPS rescue module for long-range cruising
- Practice more inverted yaw spins