Multirotor Acronyms, Terms, and More…

I’m learning about Quadrotors, Tricopters, Hexacopters, and other multirotors and I have noticed that there are a bunch of acronyms, terms, and definitions that I don’t know. This is typical when learning any new hobby.  So this post is simply a list of those acronyms and terms along with a few photos and definitions. I will add more as I come across them. Feel free to leave anything I missed in the comments section and I will add it to the list.  Click on More to view the entire list.


ARTF – Almost Ready to Fly
BEC – Battery Elimination Circuit
BNF – Bind-N- Fly
ESC - Electric Speed Control
GPS – Global Posistioning System
FC – Flight Control Board
FFF – Fast Forward Flight
PNP – Plug and Play
RTF – Ready To Fly
RTH – Return To Home
RX – Receiver
TX – Transmitter

Radio Types: 

The following Acronyms are in reference to the RF modulation techniques which the radios use.

  • PPM – Pulse Position Modulation [Old School]
  • PCM – Pulse Code Modulation
  • DSM – Digital Spread Spectrum Modulation [Newest]
  • DSSS – Direct Sequence Spread Spectrum Modulation


Li-Po Battery:

  • 1S – 1 Cell = 3.7 volts
  • 2S – 2 Cells = 11.1 volts
  • 3S – 3 Cells = 11.1 volts
  • 4S – 4 Cells = 14.8 volts

Mode: refers to how the sticks on a radio controller are configured.

  • Mode 1 – Left Stick (Pitch and Yaw) Right Stick (Throttle and Roll)
  • Mode 2 – Left Stick (Throttle and Yaw) Right Stick (Pitch and Roll) [Typical in USA]
  • Mode 3 – Left Stick (Pitch and Role) Right Stick (Throttle and Yaw)
  • Mode 4 – Left Stick (Throttle and Roll) Right Stick (Pitch and Yaw)

Types of Airframes:

I have learned that you can get very creative with your air frame.  The following is a list of common air frames but by no means are they the only types of air frames.

  • Bi-copter – Two motors.

  • Tri-copter - Three motors in a “Y” shape usually 120 degrees apart.  One motor moved by a servo and yaw mechanism to allow yaw.

  • Quad-copter - Four motors in an H, X or + configuration usually 90 degrees apart.  Four motors on the same level with two sets of CW and CCW props. The most popular frame type and mechanically the simplest.  Frames are often symmetrical but not always.  A popular frame choice for aerial photography (AP) or first person view (FPV) is an “H” configuration which allows a camera to be placed on the frame well forward to avoid having propellors in the view of the camera.

  • Hexa-copter - Six motors on the same level with three sets of CW and CCW props.

  • Y6 -  6 motors in a “Y” shape.  Similar in shape to a tricopter but has two motors, one above and one below, on each of the three arms.  Uses CW and CCW props rather than a servo to induce yaw.
  • Y6

    Octo-copter - Eight motors on the same level with four sets of CW and CCW props.

  • X8 - Eight motors on an “X” shaped frame with four sets of CW and CCW props.

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