Quick summary
A 30.5×30.5 mounting pattern means the FPV flight controller has four mounting holes arranged in a square, with 30.5 mm between the centers of adjacent holes. This is one of the most common standards for 5-inch and larger FPV quads, and it determines whether the board fits a given frame and stack. It is not the board size itself. For schools, drone soccer teams and clubs, matching this pattern correctly avoids frame modifications, loose stacks and wasted budget.
Key Takeaways
- 30.5×30.5 mm refers to hole spacing, not board dimensions.
- It is a de facto standard for many 5-inch FPV frames and stacks.
- Always confirm hole spacing, hole diameter and screw size together.
- Soft-mounting and stack height affect fit as much as the pattern.
- For team kits, standardize on one pattern to simplify spares and repairs.
What exactly does 30.5×30.5 measure?
The numbers describe the distance between the centers of two adjacent mounting holes, measured in millimeters. Because the four holes form a square, the same spacing applies horizontally and vertically. The board itself is usually larger than 30.5 mm in both directions, because the holes sit inboard of the edges.
This is why a “30.5×30.5 flight controller” and a “30.5×30.5 frame” are compatible only if the hole pattern matches. The board outline can vary between manufacturers while the hole pattern stays the same.
Why 30.5×30.5 became a common standard
As FPV quadcopters grew from small frames to 5-inch and larger builds, manufacturers converged on a small number of hole patterns to let parts mix. The 30.5×30.5 pattern is widely used because it offers a stable footprint for a flight controller and a four-in-one ESC in a stack, while leaving room for solder pads and connectors.
Betaflight, the most widely used flight controller firmware, runs on hardware from many manufacturers; its documentation notes that support for each board comes from its manufacturer. This means the mounting pattern is a mechanical choice you make before firmware enters the picture. See Betaflight’s getting-started documentation for how flight controllers fit into the wider system: https://betaflight.com/docs/wiki/getting-started.
For a broader view of the electronics that surround the flight controller, see our FPV electronics category.
30.5×30.5 vs other common mounting patterns
Mounting patterns are not interchangeable. The table below compares the patterns most often seen in school, club and drone soccer builds. Values are general industry guidance; always confirm against the specific frame and board datasheet.
| Pattern | Typical use | Practical notes |
|---|---|---|
| 25.5×25.5 mm | Smaller frames, some cinewhoops and compact builds | Lighter stacks; check board outline and connector clearance |
| 30.5×30.5 mm | Many 5-inch freestyle, racing and drone soccer frames | Common stack standard; verify hole diameter and screw size |
| 20×20 mm | Micro quads and tiny whoops | Limited space for pads; watch stack height |
| 16×16 mm | Very small builds | Specialist use; fewer stack options |
If your program runs mixed frame sizes, standardizing on 30.5×30.5 for the main fleet can reduce spare-part confusion. Our flight controllers category is organized to help you compare options.
What else must match besides the 30.5×30.5 spacing?
Hole spacing alone does not guarantee a fit. The hole diameter, screw size, board outline, stack height and connector placement all affect whether a flight controller works in a given frame.
Hole diameter and screw size
Common FPV mounting screws are M3, but the hole in the board or grommet may be sized for a specific screw and soft mount. Confirm the recommended screw size and whether soft mounts are supplied with the frame or board.
Stack height and spacing
In a stack, the flight controller sits above or below an ESC. The standoff length and the height of connectors and pads determine whether the boards clear each other. A 30.5×30.5 board from one brand may not fit another brand’s stack hardware without different standoffs.
Connector and pad layout
USB port position, battery pad location and receiver wiring can conflict with frame arms or camera mounts. Check a top and bottom view of the board before ordering in volume.
How the flight controller fits into the electronics stack
The flight controller reads sensors, computes control outputs and sends commands to the electronic speed controllers (ESCs), which drive the motors. Betaflight’s documentation describes the flight controller as a computer that reads sensors such as the gyro and accelerometer, computes desired actions and sends commands to the ESC. See the Betaflight getting-started page for this overview: https://betaflight.com/docs/wiki/getting-started.
Because the flight controller and ESC often share a mounting pattern, buying them as a matched stack reduces mechanical risk. If you source separately, compare hole patterns, standoff heights and wiring conventions. Our electronic speed controllers page lists related options.
Common mistakes when buying by mounting pattern
- Confusing hole spacing with board size. A 30.5×30.5 pattern does not mean the board is 30.5 mm wide.
- Ignoring hole diameter. M3 screws may fit some boards but not others without the correct grommets.
- Assuming stack compatibility. Two boards with the same pattern can still differ in standoff height and connector clearance.
- Forgetting soft mounting. Vibration isolation affects flight performance and is often part of the frame or board design.
- Buying one-off boards for a team. Mixed patterns increase spare-part complexity and downtime.
Procurement checklist for schools, clubs and teams
Use this checklist before placing a team order. It separates confirmed specifications from items you should ask the supplier to confirm in writing.
- Confirm the frame’s mounting pattern and hole diameter.
- Confirm the flight controller’s mounting pattern and hole diameter.
- Confirm screw size and whether soft mounts are included.
- Confirm stack height compatibility with your chosen ESC.
- Check USB and connector clearance against the frame.
- Ask for a top and bottom board image or drawing.
- Request the firmware target and manufacturer hardware support information.
- For volume orders, request written confirmation of commercial terms, lead times and warranty.
If you also need video equipment for your builds, our FPV video receivers and FPV DVR pages may help you plan a complete electronics package.
Planning a fleet refresh or a new drone soccer season? Tell us your frame pattern and team size, and we can help you shortlist compatible flight controllers. Request a Team Kit Quote.
Frequently asked questions
Is 30.5×30.5 the same as 30.5 mm board size?
No. It is the distance between mounting hole centers. The board outline is usually larger, and it varies by manufacturer.
Can I use a 30.5×30.5 flight controller on a 25.5×25.5 frame?
Not directly. You would need an adapter or a different frame. Confirm both patterns before ordering.
What screw size is used with 30.5×30.5 mounting?
M3 is common, but hole diameter and soft-mount design vary. Confirm the recommended screw and grommet with the supplier.
Does the mounting pattern affect firmware choice?
No. Firmware compatibility depends on the board’s target and manufacturer support, not the hole pattern. Betaflight documentation notes that hardware support comes from the manufacturer; see Betaflight getting started.
Why do some teams standardize on 30.5×30.5?
It is widely used on 5-inch-class frames and stacks, which can simplify spares and repairs across a fleet. Confirm your specific frame and board combination.
What should I request from a supplier before a bulk order?
Ask for written confirmation of mounting pattern, hole diameter, screw size, stack height, firmware target and commercial terms such as lead time and warranty.
Can a 30.5×30.5 flight controller fit different frame brands?
Often yes, but only if hole spacing, hole diameter and clearance match. Always check the frame drawing and board dimensions.
Conclusion
A 30.5×30.5 mounting pattern is a hole-spacing standard, not a board size. It is a useful starting point for compatibility, but hole diameter, stack height, connector clearance and screw size decide whether a flight controller actually fits. For schools and teams, standardizing on one pattern where possible reduces spare-part confusion and keeps more drones flying.
Ready to equip your team? Request a Team Kit Quote and share your frame pattern, fleet size and timeline.