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The flight controller is your drone’s brain. It reads the gyro, runs the control loop, talks to the receiver, ESC, VTX and GPS, and decides exactly how fast every motor should spin. Choosing the right one comes down to a few specs.
Processor: F4, F7 or H7
These names refer to the STM32 processor family (or equivalents) on the board.
| Processor | Speed | Best for |
|---|---|---|
| F4 | ~168 MHz | Budget and whoop builds; fine for most freestyle flying |
| F7 | ~216 MHz | More UARTs and headroom; a good all-round choice |
| H7 | ~480 MHz | GPS, ArduPilot/iNav, heavy filtering, future-proof builds |
For a Betaflight freestyle build, F4 and F7 both work well. For ArduPilot or a build with GPS, telemetry and a companion computer, an H7 gives you room to grow.
Mounting size
- 30.5×30.5 mm: standard for 5-inch and larger.
- 20×20 mm: common on 3-inch and lighter 5-inch builds.
- 25.5×25.5 or 26.5×26.5 mm: typical whoop AIO boards.
Match your frame and ESC. Most builders buy an FC and ESC together as a stack.
UARTs: count your devices
Each serial device needs a UART. List what you’ll connect:
- Receiver
- VTX control or digital video
- GPS
- Telemetry or companion computer (for ArduPilot)
A freestyle quad with GPS needs at least three free UARTs. Buy a board with one or two more than you need now.
Gyro
The gyro (IMU) measures rotation. Common chips include the ICM-42688-P, BMI270 and MPU6000. Most modern gyros are good. What matters more is soft mounting and clean wiring. Check that your firmware supports the gyro on the board.
Other features to look for
- Barometer: needed for altitude hold on ArduPilot and iNav; optional for Betaflight.
- Blackbox flash memory: records flight data for tuning. 8 MB or more, or an SD card slot.
- Onboard regulators (BECs): 5 V for receivers and GPS, 9–10 V for digital VTX units.
- Current sensor: usually on the ESC, so the FC can show mAh used.
- Solder pads vs connectors: big pads are easier to solder; plug connectors make repairs easier.
Firmware support
Make sure the board has a target for the firmware you want:
- Betaflight: freestyle and racing.
- iNav: FPV with navigation features.
- ArduPilot: autonomous missions, survey, companion computers. See PX4 vs ArduPilot.
Wiring planning before you buy
Draw your wiring before you order. For each device, list:
| Device | Connection | Voltage |
|---|---|---|
| Receiver | UART (RX/TX) | 5 V |
| Digital VTX | UART + power | 9–10 V or battery |
| GPS | UART (+ I2C for compass) | 5 V |
| LED strip | LED pad | 5 V |
| Buzzer | Buzzer pads | 5 V |
| Camera (analog) | Video in | 5 V |
Then check that the board you want has enough UARTs and regulators to cover everything.
Regulator current limits
Onboard regulators have current limits, often around 1.5–3 A on a 5 V output. Add up the current of everything you power from it. A GPS, receiver and LED strip can approach that limit, and a regulator that overheats can reset the flight controller in flight.
Flight controller orientation
Most boards have an arrow that should point forward. If you mount the board rotated, set board alignment in Betaflight’s Configuration tab (or AHRS_ORIENTATION in ArduPilot). Always check that the 3D model moves correctly before your first flight.
Common flight controller failures
- Pads ripped off by a crash pulling wires: use strain relief and leave a little slack.
- Regulator failure from a short on a 5 V device.
- Dead gyro after a hard impact: Betaflight will show no gyro or erratic data.
- Static damage: touch a grounded object before handling boards.
Our quick picks by build
| Build | Suggested FC |
|---|---|
| Tiny whoop | 1S AIO with built-in ELRS |
| 5-inch freestyle | F7 30.5×30.5 stack |
| 7-inch long range | F7 or H7 with 5+ UARTs |
| GPS / autonomous | Pixhawk-class or H7 running ArduPilot |
Frequently Asked Questions
Is an F4 flight controller good enough?
For most Betaflight freestyle and whoop builds, yes. F7 and H7 boards add more UARTs and processing headroom for GPS, ArduPilot and heavy filtering.
What is a flight controller stack?
A flight controller and 4-in-1 ESC designed to mount together, connected by a short harness cable. Buying a stack ensures the two are compatible.
How many UARTs do I need on my flight controller?
One for each serial device, such as the receiver, VTX, GPS and telemetry. Buy a board with at least one spare.
Can I run ArduPilot on an FPV flight controller?
Many H7 and some F4/F7 FPV boards have ArduPilot targets. Check the ArduPilot list of supported boards before buying.