I started a new project this week whilst waiting for some parts for a different build. It started as an exercise in CAD with no really idea that it might become real. As the week has gone on though I have enjoyed myself so much, and the response on Instagram been so big that I've decided to see how far I can get.
The plan is to see if I can build a 1:12 scale Harrier, capable of taking off and landing vertically. My starting point is to use a kk2 board and a 90mm EDF. I found this guy, Joel Vlashoff, on YouTube who has done some amazing work with VTOL aircraft, starting with a Harrier and latterly a F35, check him out here. His larger scale Harrier used a 130mm fan, with roll control from a reaction control system, but crucially, he used another 2, smaller EDF's front and back for pitch. I want to use a reaction control system for pitch as well as roll if possible, although I'm also wondering if it might be possible to use these 20mm EDF's.
I plan on using 2 standard size servos to control the thrust vector translating arms, one on each side, this will allow my some yaw control as well as transition to and from forward flight. The roll RCS valves will be controlled by one micro servo, as will the pitch RCS valves.
One of my aims for the design would be that it is 3D printable and can feature on my website. This means that it cant be too complicated. Using LW-PLA I plan to build it so that the fuselage prints in sections with all the ducting integral to the fuselage.
I have had lots of people point out that the kk2 board is old, and I would have to agree. That said, I am familiar with OpenAreoVTOL after using out on the AW609 last summer. If it turns out that the KK2 is the weak link I can then switch it out for a Pixhawk4 Mini.
My concerns at this stage are a many and I put my chances of successfully developing this at 50%. the details of the build will likely change, I'm already thinking about using a bigger fan! I'm going to learn a lot and have some fun along the way.