RC GLOSSARY
RC terminology, abbreviations and definitions
COMMON ABBREVIATIONS
| TERM | FULL FORM | MEANING |
|---|---|---|
| AIO | All-In-One | FC and ESC combined on a single board |
| AUW | All-Up Weight | Total flying weight including battery |
| BEC | Battery Eliminator Circuit | Voltage regulator converting main battery voltage to servo/receiver voltage (usually 5V) |
| BLHELI | — | Popular ESC firmware for FPV (BLHeli_S, BLHeli_32, AM32) |
| CG / CoG | Centre of Gravity | Balance point of the aircraft. Critical for stable flight. |
| CRSF | Crossfire Serial Format | Digital RC protocol used by TBS and ELRS systems |
| CVD | Constant Velocity Driveshaft | Driveshaft that delivers power smoothly at any angle |
| DSHOT | Digital Shot | Digital ESC protocol — no calibration, error detection built in |
| ELRS | ExpressLRS | Open-source long-range RC radio protocol using LoRa modulation |
| ESC | Electronic Speed Controller | Controls motor speed by varying power from battery to motor |
| FC | Flight Controller | The main board that reads sensors and controls motors |
| FDR | Final Drive Ratio | Total gear reduction from motor to wheels/prop shaft |
| FOV | Field of View | Angle of camera's visible area in degrees |
| FPV | First Person View | Flying with a live video feed to goggles or screen |
| GRP | Glass Reinforced Plastic | Fibreglass — common hull material |
| HDZero | — | Low-latency digital FPV video system |
| IMU | Inertial Measurement Unit | Gyroscope + accelerometer package on the FC |
| KV | — | Motor RPM per volt (no-load) |
| LiPo | Lithium Polymer | Standard RC rechargeable battery chemistry |
| LIPO 1S–6S | — | Number of cells in series in a LiPo pack |
| LoRa | Long Range | Radio modulation used by ELRS and Crossfire for long-range RC links |
| LVC | Low Voltage Cutoff | ESC protection that cuts power when battery drops too low |
| mAh | Milliamp Hours | Battery capacity — how much current it can supply for one hour |
| MTOM | Maximum Take-Off Mass | Maximum total weight a drone is rated/permitted to fly at |
| OSD | On-Screen Display | Data overlaid on FPV video feed (battery, speed, RSSI etc.) |
| PPM | Pulse Position Modulation | Older RC protocol carrying all channels on one wire |
| PWM | Pulse Width Modulation | Analog control signal for servos and legacy ESCs |
| RTF | Ready To Fly | Complete kit — no assembly needed |
| RTR | Ready To Run | Complete kit for ground vehicles — no assembly needed |
| RX / RX | Receiver | Radio receiver in the model |
| SBUS | Serial Bus | FrSky/Futaba digital RC protocol — 16 channels on one wire |
| SBEC | Switching BEC | High-efficiency switching voltage regulator built into ESC |
| T:W | Thrust-to-Weight | Ratio of motor thrust to total aircraft weight |
| TPU | Thermoplastic Polyurethane | Flexible 3D printing material used for mounts, bumpers, ducts |
| TX | Transmitter | The radio controller held by the pilot |
| UBEC | Universal BEC | External switching BEC, separate from ESC |
| VLOS | Visual Line of Sight | Pilot can see the aircraft without aid at all times |
| VTX | Video Transmitter | FPV video transmitter on the aircraft |
| WHR / Wh | Watt Hours | Total energy stored in battery (voltage × amp-hours) |