I flew and built a lot of gas planes as a kid, and I have a small toyish 4-prop drone that I can fly around and do flips. It has some stabilization but nothing fancy. It's about the size of my hand. I also have a couple CP 3D helicopters that I got to hover, but not spent the time to actually learn to fly it (Szabo style). There is a gyro but no fancy stabilization. I might even want to add something to that if it exists...
This was not indicated in your initial post, so most people probably assumed like I did that you were a complete noob who saw a video of a cool "drone" and decided you wanted to build one of your own. RC forums tend to be filled with noob posts like that so it's understandable that would be the assumption if it is not said otherwise.
Well, I'm not sure if newb isn't still appropriate. The RC planes were 20 years ago. I'm sure tech is much different now. Also, the drone I have was a $19 toy, so I do not think that has given me any knowledge of anything significant. It's a palm sized indoor flyer.
I was just looking at my Helios, they are the Honey Bee King 2 models. I flew one of them a few times to get a hover a few feet off the ground. I read a bit and it seems the gyro only affects the tail rotor speed or pitch to help prevent weather veining.
So, yeah, I saw a cool video and wanted to build something.
Here is what I'm thinking.
A2212 2200 kV motors with 30A SimonK ESC and 7x4E props for $6 each.
There are a couple inexpensive F4 FCs - either the $14 or a $30 one (I almost went for CC3D, and that is a newb mistake).
I might rip the radio out of one of my helios (72 MHz AM), but I have an inkling it does some kind of mixing that I wont be able to work around...or buy an inexpensive radio set. Any suggestions?
I'd run a 3S pack and the body size is looking like 250 to 300, which I would make either 3d print or just flat fibre board.
Is that coming in about right?
Now I think I should go play with betaflight software and see what it does... Can an F4 controller do anything for my helios, like replace the gyro and hover the helo automatically so I'd have to actually fly it into something to crash? I think I would do that first! I'm too scared to fly them because I know it will crash. That little drone is easy to fly.