📖 FPV glossary

The words of FPV drones, explained so anyone can understand them.

FPV

First Person View: you fly watching what the drone's camera sees through goggles, as if you were inside.

KV

Revolutions per minute a motor turns per volt. More KV = faster; with more battery cells you use less KV.

Stator (2207, 1404…)

Motor size: the first two digits are the width and the last two the height, in millimetres.

Cells (1S, 4S, 6S…)

Number of battery cells in series. Each LiPo cell is 3.7 V nominal: 6S ≈ 22.2 V.

mAh

Battery capacity. More mAh = more flight time, but also more weight.

LiPo

Lithium polymer battery: delivers lots of power at once. The most used for freestyle and racing.

Li-ion (21700 / 18650)

Batteries made of cylindrical cells: much more flight time per gram but less power. Ideal for long range. 21700 is the newest format.

ESC

Electronic speed controller: takes orders from the flight controller and drives the motors. Rated in amps.

Flight controller (FC)

The brain of the drone: it reads the sensors and the radio and decides how to drive each motor.

Stack

Flight controller and ESC mounted one on top of the other with the same bolt pattern (20x20, 25.5x25.5, 30.5x30.5).

AIO

All In One: flight controller and ESC (sometimes the receiver too) on a single board. Typical on small drones.

VTX

Video transmitter: sends the camera image to your goggles.

Air Unit

Digital video module that combines camera and transmitter, like the DJI O4 Air Unit or the O4 Air Unit Pro.

ExpressLRS (ELRS)

Open-source radio system, fast, cheap and with lots of range. It's the current standard in FPV.

Gemini

ExpressLRS mode that sends the signal over two links at once: if one fails, the other keeps going.

Diversity

Receiver with two antennas: it always uses the one with the best signal and avoids dropouts.

Crossfire

TBS long-range radio system at 900 MHz.

Betaflight

The most used software to configure the flight controller: modes, motors, receiver, filters…

Acro mode

Flight mode without self-levelling: the drone stays at the angle you leave it. It's what FPV pilots use.

Angle mode

Self-levelling mode: when you let go of the sticks the drone levels out again. Only useful for the first few days.

Tiny whoop

Tiny drone (65-75 mm) with prop guards, for flying at home.

Cinewhoop

Drone with prop guards designed to film close to people and objects.

Toothpick

Ultralight 2-3" drone with very thin arms.

Long range

Drones (7" or bigger) built to fly far and for a long time, usually with GPS and Li-ion.

Smoke stopper

Protector you put between the battery and the drone on the first power-up: it cuts the current if there's a short.

XT60 / XT30

Battery connectors. XT60 for 5" drones and up; XT30 for small drones.

Failsafe

What the drone does if it loses the radio signal: normally it stops (or flies home with GPS).

GPS Rescue

Betaflight feature that, with GPS, brings the drone back if you lose signal.