Several detailed illustrations of a generic quadrotor drone with lettered callouts indicating the various components.Illustration by Rob Nance

A. STANDARD PROP

The same “tractor” propeller used on standard front-engine R/C airplanes.

B. “PUSHER” PROP

These contra-rotating props exactly cancel out motor torques during stationary level flight. Opposite pitch gives downdraft.

C. MOTOR

Usually a brushless electric “outrunner” type, which is more efficient, more reliable, and quieter than a brushed motor.

D. MOTOR MOUNT

Sometimes built into combination fittings with landing struts.

E. LANDING GEAR

Designs that need high ground clearance may adopt helicopter-style skids mounted directly to the body, while designs with no hanging payload may omit landing gear altogether.

F. BOOM

Shorter booms increase maneuverability, while longer booms increase stability. Booms must be tough to hold up in a crash while interfering with prop downdraft as little as possible.

G. MAIN BODY

Central “hub” from which booms radiate like spokes on a wheel. Houses battery, avionics, cameras, and sensors.

H. ELECTRONIC SPEED CONTROLLER (ESC)

Converts DC battery power into 3-phase AC for driving brushless motors.

I. FLIGHT CONTROLLER

Interprets input from receiver, GPS module, battery monitor, and onboard sensors. Regulates motor speeds, via ESCs, to provide steering, as well as triggering cameras or other payloads. Controls autopilot and other autonomous functions.

J. GPS MODULE

Often combines GPS receiver and magnetometer to provide latitude, longitude, elevation, and compass heading from a single device.

K. RECEIVER

Often a standard R/C radio receiver unit. The minimum number of channels needed to control a quad is 4, but 5 is usually recommended.

L. ANTENNA

Depending on your receiver, may be a loose wire whip or helical “rubber ducky” type.

M. BATTERY

Lithium polymer (LiPo) batteries offer the best combination of energy density, power density, and lifetime on the market.

N. BATTERY MONITOR

Provides in-flight power level monitoring to flight controller.

O. GIMBAL

Pivoting mount that rotates about 1, 2, or 3 axes to provide stabilization and pointing of cameras or other sensors.

P. GIMBAL MOTOR

Brushless DC motors can be used for direct-drive angular positioning, too, which requires specially-wound coils and dedicated control circuitry that have only recently become commercially available.

Q. GIMBAL CONTROLLER

Allows control of direct-drive brushless gimbal motors as if they were standard hobby servos.

R. CAMERA

GoPro or other compact HD video unit with onboard storage. Real-time streaming is possible with special equipment.

Sean Michael Ragan

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and makezine.com. My work has also appeared in ReadyMade, c’t – Magazin für Computertechnik, and The Wall Street Journal.