The definition of a drone is broad and it covers rotorcraft, fixed wing, experimental craft, and lots of things that haven’t been created yet. When I got my first drone I was driven by the needs of a photographer/videographer so I gravitated towards the hovering rotorcraft commonly called a quadcopter. If you’re coming at this as a pure RC enthusiast then your needs will be different and you might find a fixed wing aircraft more appropriate.
I chose to build a drone instead of buying one off the shelf for two main reasons. The first reason is that I wanted more capabilities than any off the shelf unit provided, at least in my price range. The second reason is that I’m a tinker and I just love to build things like this. This is an important thing to know about yourself because you can easily try to convince yourself that you’re trying to save money, and going this route is a dubious way to save money.
The primary capability I wanted in a drone was flexible camera function. Starting with a smaller frame makes the cost of replacing broken parts easier to bear, but it has to be big enough to fly a camera/gimbal combination. With these factors in mind I chose an F450 Flamewheel frame as a first project. I also chose a motor/ESC combination that was matched to that frame. Both are made by DJI, so I effectively had the same specs as a Phantom, but I got to build it myself.
I looked for a purchaser with a good reputation in the various forums and settled on HobbyWireless for my first purchases. They have a peculiar communication paradigm and clearly don’t like to be called on the phone, but otherwise I have no complaints about them at all. As always, be cautious about what you try to buy on ebay and similar sites. It is a good way to go if you know exactly what you want and are prepared to get some useless junk in the process.
The next big question is what flight controller to use. I chose the Pixhawk running Ardupilot firmware for the same reasons that I am building a unit in the first place: it lets me tinker with it to get capabilities that go far beyond what you can find off the shelf. I’ve been a unix geek and Arduino tinkerer for years and the Pixhawk combines both of those. There are many other choices.
There are lots of build guides and videos all over the web at this stage of the game and here is my advice about them: understand that just because you watch someone do it in a video doesn’t make it the right thing to do. There are a lot of people writing about their experiences and it usually isn’t hard to find two or three sources to corroborate any given solution, so keep looking.
Start here: The DIY Drones Forum
Here is a list of the parts you’ll need to get started:
Flamewheel F450 ARF(almost ready to fly) kit
Taranis X9d Radio & Receiver