Quick Answer
Picking the right flight controller comes down to three things: processor (F7 for most pilots), mounting size (match your frame), and UART count (four minimum). The GEPRC GEP-F405-HD V2 is a capable F4 board for beginner builds, while an H7 board is worth the extra cost if you plan to run GPS or iNav.
Processor: F4, F7, or H7?
The processor determines how fast the FC thinks and what features it can handle. F4 (168MHz) is fine for basic freestyle and racing. F7 (216MHz) is the sweet spot for most pilots: fast enough for anything, with room for GPS and digital VTX. H7 (400MHz+) suits complex builds with GPS, long-range navigation, or iNav firmware.
For a deeper comparison, see our F4 vs F7 vs H7 guide.
Mounting Size
FCs come in standard sizes based on the distance between mounting holes:
- 30.5x30.5mm: The standard for 5-inch frames and larger
- 20x20mm: Smaller drones, 3-4 inch builds, and whoops
- 25.5x25.5mm: Less common, some mid-size frames
Check your frame specs before buying. Most modern 5-inch quads use 30mm mounting.
UARTs: Count Them Carefully
UARTs are serial ports for connecting external devices. Each one handles a specific job:
| Device | UARTs Needed |
|---|---|
| Radio receiver (ELRS / Crossfire) | 1 |
| GPS module | 1 |
| Digital VTX (DJI / Walksnail / HDZero) | 1 |
| ESC telemetry | Shared (optional) |
Four full UARTs is the minimum recommendation. Some budget F4 boards share UARTs between ports, meaning you can only use one device at a time. Avoid those for complex builds.
Built-in Features
Modern boards pack a lot onto one PCB. Worth having: an OSD chip (displays telemetry in your goggles), 128MB+ of blackbox flash (for flight logging), and a barometer (needed for GPS altitude hold). A current sensor is handy for tracking battery usage but not essential.
AIO boards combine the FC and ESC into one unit, which simplifies wiring and shrinks your build. The TBS Lucid Wing AIO is a popular choice for 2-6S builds. For micro quads, the HGLRC Specter AIO keeps everything compact on a 20mm board. If you want HD video with ELRS built in, the GOKU F405 HD 1S 5A ELRS AIO V2.0 supports DJI O4, Walksnail, and HDZero out of the box.
Firmware Compatibility
Betaflight works on F4 and above, and covers most freestyle and racing use cases. iNav needs F7 minimum for GPS features. ArduPilot prefers H7 hardware. If you are not sure, go Betaflight on an F7 board. That combination handles 90% of builds.
What to Buy
- TBS Lucid Wing AIO - Compact 2-6S AIO from a trusted brand
- Browse all flight controllers
- Flight stacks & towers
FAQ
Q: Can I use any FC with any frame?
A: Only if the mounting holes match. A 30mm FC will not fit a 20mm frame without adapters, and even then it may overlap other components.
Q: Do I need a barometer?
A: Only if you plan to run GPS features like altitude hold or return-to-home in iNav. Pure Betaflight freestyle pilots do not need one.
Q: AIO or separate FC and ESC?
A: AIO saves weight and wiring for smaller builds (under 5-inch). Separate boards are easier to repair if one component fails, and give you more choices for each part.