Assembly Steps
Building your first FPV quad is incredibly rewarding. Follow these steps carefully, take your time with soldering, and you'll have a machine that outperforms anything you can buy RTF. This guide covers steps 1-6: frame assembly through receiver installation.
Before You Start
- Watch a full build video for your specific frame (YouTube is full of them)
- Lay out all parts and verify everything is present
- Have your tools ready: hex drivers, soldering iron, smoke stopper
- Work on a clean, well-lit surface with a heat-resistant mat
- Set aside 2-4 hours — don't rush your first build
Step 1: Frame Assembly
Start by building the carbon fiber frame. This is the skeleton of your quad.
Instructions
- Lay out all frame pieces: bottom plate, top plate, arms, standoffs, hardware
- Identify the front of the frame (usually has a different arm shape or cutout)
- Slide the four arms into the bottom plate slots — arms should form an X pattern
- Secure arms with the provided screws (usually M3 socket head)
- Apply a tiny drop of Blue Loctite on each screw — these vibrate loose without it
- Install standoffs on the bottom plate — these hold the FC stack at the correct height
- Leave the top plate off for now — you'll install it after wiring
Frame Tips
- Tighten frame screws firmly but don't overtorque — carbon fiber can crack
- If your arms have press-fit nuts, make sure they're fully seated
- Dry-fit the stack on the standoffs to check clearance before proceeding
- Some frames have TPU antenna mounts — install these now if they mount to the frame
Step 2: Install Motors
Mount the four brushless motors to the arms. Correct placement is critical for motor direction.
Motor Placement (Standard X-Frame)
| Position | Motor # | Direction | Prop |
|---|
| Front Right | Motor 1 | CW (clockwise) | CW prop (normal thread) |
| Rear Right | Motor 2 | CCW (counter-clockwise) | CCW prop (reverse thread) |
| Rear Left | Motor 3 | CW (clockwise) | CW prop (normal thread) |
| Front Left | Motor 4 | CCW (counter-clockwise) | CCW prop (reverse thread) |
- Thread motor wires through the arm (some frames have built-in wire channels)
- Secure motors with M3 screws — usually 6-8mm length
- Use Blue Loctite on motor screws — they vibrate loose otherwise
- Leave enough wire slack to reach the ESC pads comfortably
- Label or remember which wire goes to which motor for later soldering
⚠️ CW/CCW Matters!
Getting motor direction wrong causes your quad to flip on arming. Follow the standard layout above, or check your frame's documentation. When in doubt: props-in (front motors point inward at the top) is the standard configuration.
Step 3: Solder ESC Power
The 4-in-1 ESC needs power from the battery. This is the highest-current connection and must be solid.
Power Connections
- Battery lead (XT60): Solder the positive (red) wire to the BAT+ pad, negative (black) to BAT-
- Use thick wire (12-14 AWG silicone) for the battery lead
- Tin the pads and wire ends before joining — pre-tinning makes better joints
- Apply heat to the pad first, then feed solder — don't just melt solder onto cold pads
- Hold still for 2-3 seconds after removing iron to let solder solidify
ESC Placement
Most builds stack the ESC on the bottom (closest to the frame) with the FC on top. Some prefer ESC on top for better cooling. Either works — just be consistent with your wiring plan. The ESC typically has a connector for the FC ribbon cable, plus solder pads for motor wires.
Step 4: Connect Motors to ESC
Solder the motor wires to the ESC's motor output pads. Each motor has 3 wires — all 3 must be connected.
Soldering Order
- Trim motor wires to length — not too short (no slack), not too long (excess weight)
- Strip about 2-3mm of insulation from each wire
- Tin each wire with a small amount of solder
- Tin the ESC pads briefly
- Solder wires to corresponding pads: Motor 1 → M1 pads, Motor 2 → M2, etc.
- The wire order (1-2-3) doesn't matter at this stage — motor direction is configured in software later
- Apply heat shrink to any exposed wire joints
⚠️ Don't Bridge Pads!
Motor pads are close together on 4-in-1 ESCs. Use a fine solder tip and be precise. Check with a multimeter in continuity mode between adjacent motor pads — there should be NO continuity between different motor outputs. A bridged pad = dead ESC.
Step 5: Stack the Flight Controller
Mount the FC on top of the ESC using the standoffs. Connect them with the provided ribbon cable.
Instructions
- Place rubber grommets or O-rings on the standoffs (vibration dampening)
- Set the ESC on the standoffs, threaded side up
- Connect the FC to the ESC using the 8-pin ribbon cable (or 10-pin for some stacks)
- Make sure the cable orientation matches — reversed cable = dead FC
- Place the FC on top, aligning the mounting holes with the standoffs
- Secure with M3 nylon nuts (not metal — avoid shorting the FC)
- Double-check: no wires pinched between boards, cable seated firmly
Stack Height Check
Before moving on, dry-fit the top plate to make sure the stack fits under it. If too tall, use shorter standoffs or check if the ribbon cable is routed efficiently. A tight fit is fine — just make sure nothing shorts against the carbon frame (cover exposed carbon with electrical tape if needed).
Step 6: Install Receiver
The ELRS receiver connects to the FC via serial (UART). Typically 3 wires: 5V, GND, and TX/RX.
Wiring
| Receiver Wire | FC Pad | Purpose |
|---|
| 5V | 5V pad on FC | Power the receiver |
| GND | GND pad on FC | Ground reference |
| TX | RX on FC (e.g., UART2 RX) | Receiver sends data to FC |
| RX | TX on FC (e.g., UART2 TX) | FC sends data to receiver |
- Mount the receiver antenna — it MUST extend away from carbon fiber and electronics
- Use a zip tie on the antenna arm, or a 3D-printed antenna mount
- Keep antenna wire away from ESC power wires (EMI interference)
- If using a ceramic antenna (tiny whoop ELRS RX), position it facing upward with clear sky view
⚠️ Antenna Placement is Critical
A poorly placed antenna causes failsafes — your quad drops out of the sky with no warning. The antenna must not be blocked by carbon fiber, ESC, or battery. Mount it on a zip tie extending 3-5cm from the frame, pointing up or back. Never coil or fold the antenna wire.
What's Next?
Steps 7-11 (DJI O4 installation, power-on test, Betaflight configuration, motor direction, final assembly) are covered in the Soldering & Final Setup guide.
Next: Soldering & Final Setup →