This is an excellent excellent question! A quadcopter, or multirotor, drone, or UAV, is a simple flying mechanical vehicle that has four arms, and in each arm there is a motor attached to a propeller. With the rising popularity of RC Quadcopters, it is no doubt people misuse words.
Unmanned Ariel Vehicle, aka UAV, is any Ariel Vehicle without the pilot physically in the aircraft itself. Be it the MQ-1 predator, an RC Plane, RC Helicopter, Rc Quadcopters, they are all UAVs. Autonomous aircraft are also UAVs
Drone is just a broad term that describe a Unmanned Survalence machine. It can be UAV, UGV (unmanned ground vehicle / autonomous cars), AUV (autonomous underwater vehicle), or Unmanned Spacrcraft (satellites). In the Olden Days where consumer grades RC Quads weren’t as popular, Drones were simply used to refer to Unmanned Combat Vehicle, like the Predator. Now the word is used to describe RC Quadcopters or less often, RC Planes and RC Heli.
The word “drone” is being used a lot these days and has become synonymous with any unmanned aircraft with an onboard camera, and sometimes a camera is not even necessary for the title! Other than for military use, most “drones” were historically used for aerial photography (AP) and were large with a heavy payload capacity for carrying cameras and equipment.
There is a simple introduction about quadcopter from wikipedia. A quadcopter, also called a quadrotor helicopter or quadrotor, is a multirotor helicopter that is lifted and propelled by four rotors. Quadcopters are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is generated by a set of rotors (vertically oriented propellers).
- A Helicopter has one set of rotor, or propeller, or “fans”.
- A Bicopyer has 2 sets, like a chinook.
- A Tricopters has 3 set.
- A Quadcopter, 4.
What is a Multirotor?
The word Multirotor (or Multicopter) covers anything that is a “copter” with more than 1 main motor or propeller. For example, a “tricopter” has 3 motors / rotors, a “quadcopter” has 4, a “hexacopter” has 6 etc. So the term “multi-rotor” encompasses these types of drone.
What is a Mini Quad?
A Mini Quad is basically a mini size quadcopter which is usually under 250mm. Mini quads are designed to be fast, nimble and resilient, so even when you crash you can usually just pick it up and take off again. This resilience gives pilots the confidence to fly faster, through smaller gaps, and continually push their limits to the next level.
Since this fantastic invention, we’ve seen huge progress in the power of these mini-quads, increasing propeller sizes, higher battery voltage, larger motors, all coming together to give insane power-to-weight ratios of over 14:1! Turning these little toys into insane rockets, the fastest racing drone in the world is capable of reaching 180mph(~290Kmh) in a matter of seconds.
Note that the number of rotors decide the kind of “copter” it is, not the number of booms. A aircraft with 4 booms with 8 rotors like the Ehang 184, would be classified as an octacopter, not quadcopter.
Why Quadcopter is the most popular one?
Quadcopter holds the balance between simplicity and functionality. A helicopter requires swashplate setup, which only hobbyist and professional are confident at doing, not regular consumer. A Tricopter requires a special rotating tail which is also complicated to calibrate if you don’t know how. A Quadcopter is simple to set up, allowing designer to hide the complicated stuff like flight controller in the body to avoid tampering. All you have to do is plug your battery in. DJI is currently the leading consumer brand.
A film production company might use a hexacopter or octacopter to hoist heavy cameras.