What is the difference between an AIO board and a separate FPV stack?

An AIO (All-In-One) board combines the flight controller and ESC onto a single PCB, making it lighter (5-12g) and more compact. A separate stack uses two boards (FC and ESC) connected by a harness or plug-in connector, offering higher current handling (55-65A vs 12-45A), better repairability, and more UART connections.

Should I use an AIO or a separate stack for a 5-inch FPV drone?

For a 5-inch drone, a separate stack is strongly recommended. 5-inch builds pull 80-110A during punch-outs, well beyond most AIO boards' 15-45A ratings. A separate 55A+ ESC board provides the current headroom needed for aggressive flying, and in the event of a crash, you can replace only the damaged board rather than the entire stack.

What mounting pattern should I use for my FPV build?

Use 30.5x30.5mm for standard 5-inch and larger builds. Use 20x20mm for 3-4 inch builds and lightweight 5-inch setups. Use 25.5x25.5mm (whoop pattern) for whoops and toothpicks. Use 16x16mm only for ultra-light micro builds. Always verify your frame supports your chosen mounting pattern before buying.

Can I upgrade just my ESC or FC in a separate stack?

Yes — that's one of the primary advantages of a separate stack. If your ESC fails, you can replace only the ESC board while keeping your FC, preserving your Betaflight configuration. If you want to upgrade your FC for more UARTs or a faster processor, you can keep your existing ESC. Just ensure the new board uses the same mounting pattern and connector type.

FPV Drone Stack Selection: AIO vs Separate ESC and Flight Controller

# FPV Drone Stack Selection: AIO vs Separate ESC and Flight Controller

The flight stack is the brain and muscle of your FPV drone. Choosing between an All-In-One (AIO) board and a separate ESC + Flight Controller stack is one of the first decisions you’ll make when planning a build. Each approach has distinct advantages, and the right choice depends entirely on your build size, flying style, and repair philosophy.

## What Is a Flight Stack?

A “stack” traditionally refers to two separate boards mounted on top of each other:
– **Flight Controller (FC):** The brain — gyro, processor, OSD chip, and all UART connections.
– **ESC (Electronic Speed Controller):** The muscle — converts FC signals into 3-phase power for the motors.

An **AIO board** combines both onto a single PCB, with the ESC circuitry and FC circuitry on the same board.

## Comparison: AIO vs Separate Stack

## When to Choose AIO

### Ideal AIO Use Cases
– **Tiny Whoops (65-85mm):** The only practical option. Weight is everything.
– **2.5-3.5 inch Toothpicks:** AIO keeps the build light and nimble.
– **Sub-250g AUW Builds:** Every gram counts when trying to stay under the 250g regulatory threshold.
– **Budget Micro Builds:** A $40 AIO replaces a $60-80 stack.

### Recommended AIO Boards

### AIO Drawbacks

## When to Choose a Separate Stack

### Ideal Stack Use Cases
– **5-inch Freestyle/Racing:** The standard. A proper 55A+ ESC handles aggressive flying.
– **7-inch Long Range:** Needs high-current ESCs for big motors and heavy props.
– **Any Build Over 400g:** Stacks provide the current headroom and durability needed.
– **High-Performance Tuning:** Separate boards allow individual replacement and upgrade.

### Choosing the Right Stack Size

| Mounting Pattern | Typical Use | FC Size | ESC Size |
|—————–|————-|———|———-|
| 16x16mm | Micro 2-3 inch | 16x16mm | 16x16mm |
| 20x20mm | 3-4 inch, sub-250g 5″ | 20x20mm | 20x20mm |
| 25.5×25.5mm (Whoop) | Whoops, toothpicks | 25.5×25.5mm | N/A (usually AIO) |
| 30.5×30.5mm | 5-inch standard | 30.5×30.5mm | 30.5×30.5mm |

### Recommended Stacks

| Stack | ESC Rating | Processor | Best For |
|——-|———–|———–|———-|
| SpeedyBee F405 V4 55A | 55A | F405 | All-around 5-inch |
| Mamba F722 MK4 55A | 55A | F722 | High-performance freestyle |
| Holybro Kakute H7 65A | 65A | H743 | 7-inch, heavy builds |
| T-Motor F7 55A | 55A | F722 | Premium freestyle |
| Diatone Mamba F405 40A | 40A | F405 | Budget 5-inch |

## Wiring: AIO vs Stack

### AIO Wiring
AIO boards simplify wiring because there’s no ESC-to-FC connector. All motor pads, battery leads, and peripheral connections go to one board:
“`
[Battery +] → [AIO Board]
[Motors 1-4] → [AIO Board motor pads]
[RX, VTX, Camera, GPS] → [AIO Board UARTs]
“`

### Separate Stack Wiring
Stacks need an ESC-to-FC harness (or plug-in connector):
“`
[Battery+] → [ESC Power Pads] → [FC via 8-pin or 10-pin harness]
[Motors 1-4] → [ESC motor pads]
[RX, VTX, Camera, GPS] → [FC UARTs]
“`

The harness/connector is a common failure point — always secure the ESC-to-FC connector with a zip tie.

## Cost Analysis: AIO vs Stack Over Time

Consider a crash that damages one ESC:

Over 2-3 crashes, the separate stack often saves money despite the higher initial cost.

## Decision Framework

**Choose AIO if:**
– Your build is ≤ 3.5 inches
– You’re targeting sub-250g AUW
– Budget is your primary constraint
– You’re building a micro/whoop

**Choose Separate Stack if:**
– Your build is ≥ 5 inches
– You fly aggressively (freestyle/racing)
– You want to replace individual components after crashes
– You need many UARTs for GPS, Compass, VTX control, Camera control, and RX

## Product Recommendation

For 5-inch builds, the **SpeedyBee F405 V4 Stack (55A)** offers the best balance of features, price, and reliability. Built-in Bluetooth for field tuning, 6 UARTs, and a robust 55A 4-in-1 ESC make it the go-to choice for both beginners and experienced pilots. Available at [uavmodel.com](https://uavmodel.com).

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