Hardware · DIY practice rig

DIY 5-inch racer build.

A reproducible 5-inch FPV quadrotor used for real-flight data capture and sim-to-real bridge work in July–August. Specifically sized and configured to match what comes out of the virtual qualifier: a single front-facing camera, IMU, 4-axis control.

Class

5-inch FPV freestyle / race

commodity parts

Target TWR

5–6×

race-class

Compute

Jetson Orin Nano 8GB

per Physical spec class

Camera

RPi Camera 3 Wide

match Archer spec when known

§ 01Bill of materials

Category	Part	Qty	Notes
Frame	iFlight Nazgul5 V3 · TrueX 5"	1	Stiff TrueX geometry, room for Orin stack
Flight controller	Holybro Kakute H7 V2	1	H7 MCU, plenty of headroom
ESC	Holybro Tekko32 F4 4-in-1 · 50A	1	6S-capable, BLHeli_32
Motors	iFlight XING2 2207 · 2750 KV	4	6S-matched, 5-inch prop
Propellers	HQProp 5×4.3×3 V1S	4 + spares	Balanced, triblade
Battery	Tattu R-Line 1300 mAh · 6S · 120C	3	Race pack; 3 for rotation
Compute	Jetson Orin Nano 8GB Super	1	Matches expected Archer class
Camera	RPi Camera Module 3 Wide	1	120° FOV, 12MP, IMX708
VTX (telemetry only)	Rush Tank Ultimate Mini	1	OSD debug + human spotter only
Receiver	ExpressLRS 2.4 GHz EP2	1	Kill-switch · safety only; autonomy is onboard
Radio (transmitter)	Radiomaster Boxer ELRS	1	Safety pilot for test flights
Props guards	5" prop guards (printed)	4	Use during indoor training

§ 02Assembly order

Frame arms + bottom plate (x 8 screws).
Mount motors — confirm CW / CCW placement matches ESC expectation.
Solder motor leads to ESC pads. Check for shorts before power.
Mount ESC to bottom plate with soft mounts (4 × M3 × 6).
Solder XT60 lead + capacitor to ESC PDB side.
Stack flight controller on top of ESC via included vibration isolators.
Connect ESC signal cable to FC motor outputs (S1–S4).
Wire RX (UART6) + VTX (UART3) + camera trigger + Orin UART bridge.
Mount Orin Nano on top plate with 3D-printed bracket (see 3D parts).
Run RPi Camera 3 Wide via CSI ribbon to Orin. Secure with strain-relief clip.
Final pass: cable ties, goop, balance check, vibration test.

§ 03Wiring summary

Battery (6S 1300) ──► XT60 ──► ESC PDB ──► Motor 1..4
                                │
                                ├──► FC (Kakute H7) ── Orin Nano (UART MAVLink)
                                │
                                ├──► Orin 5V buck (3A headroom)
                                │
                                └──► VTX (telemetry + OSD for human spotter)

Receiver (ELRS)   ──► FC UART6     (safety pilot / kill switch)
Camera (IMX708)   ──► Orin CSI     (autonomy input)
Orin              ──► FC MAVLink   (autonomy output · SET_ATTITUDE_TARGET)

§ 04First-flight checklist

#	Check	Pass condition
1	Props off · motor spin direction	Each motor's direction matches frame layout
2	Props off · RC stick mapping	Throttle = thrust, sticks correct
3	Battery voltage at startup	> 24.8 V (6S full)
4	Failsafe arm	Disarms on RC loss within 1 s
5	Orin boot, CSI camera active	`v4l2-ctl --list-devices` shows imx708
6	Onboard MAVLink heartbeat	Orin sees FC heartbeat at 2+ Hz
7	Short hover · manual	Safety pilot can hover, land
8	Short hover · onboard autonomy (loiter)	No runaway, no oscillation
9	Short gate approach · autonomy	Pilot sees detector locked, altitude held
10	Kill-switch drill	Pilot can disarm mid-flight

§ 05Purpose: sim-to-real bridge

The DIY rig exists specifically to capture ~30 minutes of real-flight telemetry for the residual-dynamics model (playbook §04). Budget:

~10 min indoors, netted space · lightweight gate mockup · low speed
~15 min outdoors, daylight · dusk · shadow
~5 min high-dynamic · banking · recovery

This is not a race drone. It's a data-capture tool. Optimize for reliability + predictable dynamics, not top speed. Save the speed chase for Ohio.

DIY-5INCH · v2.0 2026-04-21 · ← Index · Build guide