Full Bill of Materials
This build is based on the GepRC Mark5 HD frame — the best crash-geometry 5-inch frame we tested — with DJI O3 digital FPV, a 45A 4-in-1 ESC, and a 2306 2450KV motor set. All prices are USD, April 2026.
- Frame: GepRC Mark5 HD — $89
- Motors: T-Motor F40 Pro V4 2306 2450KV ×4 — $52 (4-pack)
- ESC: Speedybee F405 Mini 45A stack — $38
- FPV system: DJI O3 Air Unit — $159 (often available used for $90–110)
- Receiver: ExpressLRS RP3 — $16
- Props: HQProp 5040 3-blade — $8 (4-pack)
- Battery: Tattu R-Line 1550mAh 6S 130C — $42
- Printed parts filament: ~$4 (30g PETG-CF + 15g TPU95)
Total: $408 with new O3, approximately $259 with used O3. The 3D printed components replace approximately $35–45 of manufactured TPU and nylon parts that would otherwise need purchasing separately.
5" FPV Frame // True X
GepRC Mark5 HD O3
- Best crash-geometry 5-inch frame we tested across 60 impact cycles
- 40+ printable accessories available — camera mounts, GPS towers, antenna tubes
- 225mm wheelbase, 4mm carbon arms, true X layout
- Designed specifically for DJI O3 — electronics fit verified
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Print List and Settings
All printable parts for this build, with material and settings. Print these before you begin assembly — you will want them ready.
- DJI O3 30° camera mount — TPU95A, 4 perimeters, 60% gyroid infill, 25mm/s, 220°C
- FC standoffs (×4, 8mm) — TPU95A, 100% infill, 4 perimeters, 25mm/s
- GPS tower (60mm mast) — PETG, 4 perimeters, 40% infill, 60mm/s, 230°C
- ELRS antenna tubes (×2) — ASA, 100% infill walls, 50mm/s, 255°C (needs enclosure)
- Battery pad inserts (×2) — TPU95A, 100% infill, 25mm/s
- Prop-off cover — PETG, 3 perimeters, 20% infill, 60mm/s
Total print time on a Bambu Lab P1S: approximately 3.5 hours for all parts. Total filament: 32g PETG-CF (arms printed in PETG-CF for stiffness), 18g TPU95A, 8g ASA.
Assembly Order
Correct assembly sequence minimises rework. Follow this order: (1) Mount motors to arms. (2) Attach arms to bottom plate. (3) Install TPU FC standoffs to bottom plate (M3 × 30mm screws through standoff). (4) Mount ESC stack on standoffs. (5) Solder motor leads (confirm motor rotation direction). (6) Mount FC on ESC stack with TPU O-rings between boards. (7) Install O3 and camera mount assembly. (8) Route and connect all cables. (9) Mount ELRS receiver and route antenna tubes. (10) Attach GPS tower and connect GPS. (11) Install top plate and secure battery strap.
First Flight Setup
Before your first flight: configure Betaflight (motor direction, mixer, receiver protocol), verify motor spin direction (props-off motor test), bind receiver and verify failsafe, set arming requirements (arm switch, throttle condition). Use a stock or very conservative PID tune for your first flights — the default Betaflight rates and PIDs will fly the aircraft safely while you develop confidence. Aggressive PID tuning comes after you understand how the build flies.