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FPV Bible

Glossary

FPV has a lot of jargon. This glossary covers the terms you’ll encounter as you learn the hobby.

A

Section titled “A”
  • Acro Mode (also Rate Mode, Manual Mode): Flight mode with no self-leveling. The drone stays at whatever angle you put it. This is how most FPV pilots fly.
  • AIO (All-in-One): A board that combines multiple components (usually FC + ESC, or camera + VTX).
  • Angle Mode: Self-leveling flight mode. Release the sticks and the drone returns to level. Training wheels for beginners.
  • Arm: Enabling the motors so the drone can fly. Done via a switch on your radio.
  • AUW (All-Up Weight): Total weight of the drone ready to fly, including battery and camera.

B

Section titled “B”
  • Backpack: Some FPV systems (ELRS, HDZero) use a “backpack” module for wireless configuration — a small WiFi-enabled board on the VTX or goggles.
  • Betaflight: The most popular open-source flight controller firmware for FPV drones.
  • Bidirectional DShot: A motor protocol that sends data both ways — FC to ESC (speed commands) and ESC to FC (RPM telemetry). Enables RPM filtering.
  • BLHeli: Firmware that runs on ESCs. BLHeli_32 (32-bit) and BLHeli_S (8-bit) are common versions.
  • BNF (Bind-and-Fly): A pre-built drone that comes ready to fly — just bind your receiver.
  • Blackbox: Betaflight’s flight data logger. Records gyro, PID, motor output, and RC input for analysis.

C

Section titled “C”
  • Cinelifter: A large drone (7-10”+) built to carry a cinema camera.
  • Cinewhoop: A ducted drone designed for safe, smooth cinematic footage.
  • CRSF (Crossfire): TBS’s proprietary long-range radio protocol.
  • Crossfire: TBS radio system for long-range control. Uses the CRSF protocol.

D

Section titled “D”
  • D-term (Derivative): The part of the PID controller that dampens overshooting. See PID Tuning.
  • Deadcat: A frame geometry where the rear motors are angled inward so props don’t appear in the camera view.
  • Demag (Demagnetization) Compensation: ESC setting that prevents motor sync issues caused by back-EMF.
  • Desync: When an ESC loses sync with the motor, causing it to stutter or stop. Often happens at low throttle.
  • DShot: A digital protocol between FC and ESC. DShot150/300/600 — higher numbers are faster.
  • DVR (Digital Video Recording): Recording of your FPV feed. On digital systems it’s built-in; on analog you need an external DVR module.
  • Dynamic Idle: Betaflight feature that adjusts idle speed dynamically to prevent desync at low throttle.

E

Section titled “E”
  • EdgeTX: Open-source firmware for radio transmitters. The actively developed fork of OpenTX.
  • ELRS (ExpressLRS): Open-source radio control protocol. Extremely low latency and long range.
  • ESC (Electronic Speed Controller): Drives a motor based on commands from the flight controller.
  • Expo (Exponential): A rate curve modifier that softens stick response near center.

F

Section titled “F”
  • F4/F7/H7: Flight controller processor types. F4 is older/budget, F7 is standard, H7 is high-end. Higher = faster, more features.
  • Failsafe: What the drone does when it loses radio signal. Should be configured before flying.
  • FC (Flight Controller): The brain of the drone. Reads sensors and controls motors.
  • FF (Feedforward): A PID controller component that reacts to stick movement speed rather than error.
  • Freestyle: Acrobatic FPV flying focused on creative tricks and flowing lines.
  • FRIA (FAA-Recognized Identification Area): Designated areas where Remote ID is not required.

G

Section titled “G”
  • GPS Rescue: Betaflight feature that uses GPS to fly the drone home if signal is lost.
  • Gyro (Gyroscope): Sensor on the FC that measures rotation rate. The most critical sensor for flight.

H

Section titled “H”
  • HDZero: A low-latency digital FPV system popular for racing.
  • Horizon Mode: A blend of Angle and Acro — self-levels at small stick inputs, allows flips at full stick.

I

Section titled “I”
  • I-term (Integral): The part of the PID controller that corrects persistent drift. See PID Tuning.
  • iNav: A Betaflight fork focused on GPS navigation and autonomous flight.

J

Section titled “J”
  • Jello: Vibration artifacts visible in video footage. Usually caused by vibrations transferring from motors to the camera. Fix with soft-mounting or balanced props.

K

Section titled “K”
  • KV (RPM per Volt): Motor rating indicating how fast it spins per volt applied, with no load. Higher KV = faster spin, lower torque. Lower KV = slower spin, higher torque. Pair high KV with small props, low KV with large props.

L

Section titled “L”
  • LAANC: FAA system for getting near-instant airspace authorization near airports.
  • Li-Ion (Lithium-Ion): Battery chemistry with higher energy density than LiPo but lower discharge rate. Used for long-range builds.
  • LiPo (Lithium Polymer): The standard battery chemistry for FPV drones. High discharge rate, good energy density.
  • Long Range: FPV builds optimized for maximum distance and flight time.
  • LQ (Link Quality): A metric showing radio link reliability. 100% = all packets received.
  • LRC (Long Range Configuration): Lower packet rates on ELRS for maximum range.

M

Section titled “M”
  • mAh (Milliamp Hours): Battery capacity. Higher mAh = more energy = longer flight (but heavier).
  • MSP (MultiWii Serial Protocol): Communication protocol between Betaflight and configurator software.
  • MultiGP: The largest FPV drone racing league.
  • Mulligan: Getting a re-do after a crash in a race (depends on race rules).

N

Section titled “N”
  • Naked GoPro: A GoPro with the housing removed to save weight. Common in freestyle builds.
  • ND Filter (Neutral Density): An optical filter that reduces light, allowing slower shutter speeds for cinematic motion blur.

O

Section titled “O”
  • OSD (On-Screen Display): Information overlaid on your FPV video feed — battery voltage, RSSI, flight time, etc.
  • OpenTX: Open-source radio firmware. EdgeTX is the current actively-developed fork.

P

Section titled “P”
  • P-term (Proportional): The main PID correction force. Higher P = snappier response. See PID Tuning.
  • Part 107: FAA certification required for commercial drone operations in the US.
  • PDB (Power Distribution Board): Distributes battery power to ESCs and other components. Largely replaced by integrated designs.
  • PID: Proportional-Integral-Derivative controller. The algorithm that makes your drone fly stable.
  • Props In/Out: Motor rotation direction. Props Out (motors spin outward at front) is the modern default.
  • Propwash: Turbulent air created by spinning propellers. Causes oscillation when a drone descends through its own wake.
  • PNP (Plug-and-Play): A pre-built drone sold without a receiver (you add your own).

R

Section titled “R”
  • Rate: How fast the drone rotates in degrees per second at a given stick position.
  • Remote ID: FAA requirement for drones to broadcast identification and location.
  • RPM Filtering: Betaflight feature that uses motor RPM data to precisely filter out motor-frequency noise.
  • RSSI (Received Signal Strength Indicator): A measure of radio signal strength. Monitor in OSD.
  • RTF (Ready-to-Fly): A package that includes everything needed to fly — drone, radio, goggles.

S

Section titled “S”
  • SBUS: A serial protocol from FrSky for connecting receiver to FC. Being replaced by CRSF/ELRS.
  • Smoke Stopper: An inline current limiter used during first power-up to prevent damage from wiring mistakes.
  • Stack: FC and ESC mounted together on standoffs. Most builds use a “stack” configuration.
  • Sub-250: A drone build under 250g total weight, which avoids FAA registration requirements.

T

Section titled “T”
  • Tiny Whoop: A small ducted FPV drone (65-85mm) designed for indoor flying.
  • Toothpick: An ultralight 2.5-3” outdoor drone on a minimal frame.
  • TPU (Thermoplastic Polyurethane): A flexible 3D printing material used for camera mounts, antenna holders, and other FPV accessories.
  • TRUST: The Recreational UAS Safety Test. Required for recreational drone flyers in the US.
  • Turtle Mode: “Flip over after crash” — a Betaflight mode that reverses motors to flip the drone upright.

U

Section titled “U”
  • UART (Universal Asynchronous Receiver/Transmitter): Serial communication ports on an FC, used to connect receivers, GPS, VTX control, etc.
  • UFL: A tiny coaxial connector used to attach antennas to VTXs.

V

Section titled “V”
  • VLOS (Visual Line of Sight): The legal requirement to see your drone with unaided eyes while flying.
  • VTX (Video Transmitter): Transmits the FPV camera’s video signal to the goggles.
  • VRX (Video Receiver): Receives the VTX signal. Usually built into goggles, or a separate module.

W

Section titled “W”
  • Walksnail: A digital FPV system by Caddx. Also known as Avatar.
  • Whoop: Short for Tiny Whoop. Any small ducted FPV drone.