So, What is a Drone?

DJi Drone in Flight

In the previous blog, I said Passerine aircraft is developing a new type of drone, but what does that mean? In this blog post, I am going to look at what a drone is, both in the commonly perceived sense and broader sense, to show how this term relates to Passerine Aircraft.

Depending on who you talk to, a drone could be many different things. For most people, a drone is a multi-rotor or multi-copter. But the word drone is also used when referring to a military UAVs, and less commonly, when referring to a remote-controlled aircraft. Let’s take a brief look at all of these:


Quadcopters, Hexacopters, Octocopters or any other number-of-rotor craft are what most people think of when someone talks about a drone. These aircraft are very easy to put together and appear to be easy to fly. They have made flying accessible to everyone in a way that fixed-wing aircraft and helicopters couldn’t. Their apparent ease of operation is achieved by using a fairly powerful onboard flight controller, so that they can basically fly themselves. The pilot simply tells them where to go.

DJI Phantom4 in flight
A quadcopter with a camera attached (Photo credit: Volatus — CC BY-SA 3.0)


An Unmanned Aerial Vehicle (UAV) or Unmanned Aerial System (UAS) usually refers to a remotely piloted military aircraft. Much like multi-rotors, they have onboard control systems, but their onboard controllers are far more advanced and basically allow UAVs to fly themselves completely autonomously. They are extremely useful to the military, as they can go into dangerous airspace with no risk posed to a pilot, and stay in the air for long periods of time. Because of their popularity with the military, UAVs are controversial and generally have an unfavourable reputation outside of the military.

The Reaper Returns
An Air Force MQ-9 Reaper landing in Afghanistan after a mission

A Bit of History

It may come as a surprise, but drones are not a recent development. In fact, the concept was experimented with during the second world war. Initially military “drones” were normal aircraft that had been modified to be controlled remotely. These aircraft were normally used as target drones to help train anti-aircraft gunners. One example of this is the Culver PQ-14 [shown below]. These aircraft have more in common with remote-controlled aircraft than drones. I’ll explain why a remote-controlled aircraft is not a drone below.

Culver PQ-14 USAF
Culver PQ-14 USAF

The Interstate TDR-1 was a little more like a modern drone than the PQ-14. It was capable of carrying weapons and had a camera fitted in the nose to allow it to be flown from further away. Even though the program to develop the TDR “assault drone” was cancelled, it still shows that the idea of using unmanned aircraft for real world missions is hardly a new one.

Interstate TDR-1 on display
Interstate TDR-1 on display at Naval Aviation Museum

A definition for a drone

All drone aircraft have two things in common,

  • They are all remotely piloted.
  • They all have some degree of autonomy (stabilisation).

These are my two requirements to be able to call an aircraft a drone.

Remote controlled aircraft

I’ve referred to remote-controlled (or radio-controlled) aircraft earlier in this post, but how are they defined? Well, when I say a remote-controlled (RC) aircraft, I am referring to a craft that is flown remotely but doesn’t have any onboard control systems. I generally don’t consider this type of aircraft to be a drone because of its lack of autonomy. It is possible to fit off the shelf controllers to remote-control aircraft to make them into autonomous drones however.

This is one area of drone use which can become quite tricky from a legal point of view. It is often difficult to tell the difference between a hobby RC aircraft and a drone. Sometimes the same aircraft will be considered differently purely based on how it is being used. Legislation on this topic can vary widely from country to country and is usually quite complicated, so I won’t journey any deeper into the legality in this post, but Wikipedia does have an article on this subject, for more general information.

Remote-Controlled Glider Flying
A remote-controlled glider in flight

Commercial drones

Recently, several companies have started developing drones specifically for commercial purposes. Often these resemble military UAV’s but have designs more suited for the civilian market. My hope is that these new aircraft can give drones in general, a better reputation with the public.

This rise in interest in commercial applications and the advancements in onboard controllers, has allowed us, at Passerine Aircraft, to research and develop a new drone that will allow companies and people to take advantage of the ease of flying usually associated with multi-rotors. Our drone does not require any ground infrastructure and allows for long range and high-speed flight. These attributes are all useful in package delivery and landscape surveying.

Sparrow Jumper Take-Off
The Passerine Sparrow Jumper about to take-off

Finally, to answer my question…

Drones are far more than multi-rotors or military UAV’s. Any remotely piloted aircraft with a flight controller can be a drone. Drones have the potential to take on many forms and many roles and this is why this technology is so exciting!

Subscribe for blog and newsletter updates