i always wondered about this...just thought I would share for the beginners like me 
The difference between a drone, UAV, and a quadcopter?
The term "drone" is lazy and inexact. However, it's also becoming like "Thermos"(TM) and "Kleenex" (TM): a common usage that most people would agree refers to X. In this case, "X" would be an unmanned aircraft, specific type undefined, but a blind flying robot of some sort. (I decline to accept the spinmeisters' attempt to call them "remotely piloted aircraft," since they have a habit of slipping their leashes and taking the pilot out of the equation way too often for my taste.)
Think of unmanned aircraft as being exactly the same as manned aircraft, but without the body or bodies inside. The only real difference is that there has to be a way of pointing them the way you want them to go from somewhere else, which for unmanned aircraft requires an electronic datalink of some type. So, unmanned aircraft might be fixed-wing airplanes, helicopters, lighter-than-air blimps, or some very creative hybrids.
Since they don't have to be built to carry the weight of a person, they can be built smaller and less expensively, with more of what they can do in terms of speed or lifting power devoted to carrying out a task of some type. They also can be built very large, capable of covering long distances or carrying very heavy payloads. The only limits are imagination and a plan for what you want to do with one.
A "quadcopter" is a generic term for a rotary-wing aircraft with four main rotor systems and no tail rotor. There's nothing that says it has to be unmanned, but common usage of the term these days has given it that implied qualifier. Also, "quadcopters" flown for hobby or recreational use (but certainly not for business, because that's not provided for in aviation rules yet) pretty much all come down at the small end of the size spectrum.
So:
1. It isn't wrong to call almost any kind of remotely or self-directed vehicle a "drone."
2. All unmanned aircraft may be considered "drones."
3. It's basically impossible to come up with a currently flying example of a quadcopter that isn't an unmanned aircraft (part of an "unmanned aircraft system") and therefore, at the end of the day... a drone.
The difference between a drone, UAV, and a quadcopter?
The term "drone" is lazy and inexact. However, it's also becoming like "Thermos"(TM) and "Kleenex" (TM): a common usage that most people would agree refers to X. In this case, "X" would be an unmanned aircraft, specific type undefined, but a blind flying robot of some sort. (I decline to accept the spinmeisters' attempt to call them "remotely piloted aircraft," since they have a habit of slipping their leashes and taking the pilot out of the equation way too often for my taste.)
Think of unmanned aircraft as being exactly the same as manned aircraft, but without the body or bodies inside. The only real difference is that there has to be a way of pointing them the way you want them to go from somewhere else, which for unmanned aircraft requires an electronic datalink of some type. So, unmanned aircraft might be fixed-wing airplanes, helicopters, lighter-than-air blimps, or some very creative hybrids.
Since they don't have to be built to carry the weight of a person, they can be built smaller and less expensively, with more of what they can do in terms of speed or lifting power devoted to carrying out a task of some type. They also can be built very large, capable of covering long distances or carrying very heavy payloads. The only limits are imagination and a plan for what you want to do with one.
A "quadcopter" is a generic term for a rotary-wing aircraft with four main rotor systems and no tail rotor. There's nothing that says it has to be unmanned, but common usage of the term these days has given it that implied qualifier. Also, "quadcopters" flown for hobby or recreational use (but certainly not for business, because that's not provided for in aviation rules yet) pretty much all come down at the small end of the size spectrum.
So:
1. It isn't wrong to call almost any kind of remotely or self-directed vehicle a "drone."
2. All unmanned aircraft may be considered "drones."
3. It's basically impossible to come up with a currently flying example of a quadcopter that isn't an unmanned aircraft (part of an "unmanned aircraft system") and therefore, at the end of the day... a drone.
