With 4 ducted fans, and some carbon fiber, I built a bladeless drone that I think is one of safest in the world. It uses 4, 90mm ducted fan propulsion units buried deep inside what I call a “bent tube” propulsor. The fifth “leg” is a parachute can. Hopefully I will never need it. With some help from my dad, we built the entire airframe primarily out of carbon fiber and some balsa wood. I bought all the electronics on line and was able to design the drone so that it would operate with a standard DJI multi rotor flight controller even though it doesn’t have vertically oriented propellers. With its top mesh installed its virtually impossible to get fingers and objects in contact with the blades. I submitted a patent application for my invention. I think a drone like this could have industrial applications where a drone needs to operate close to people, objects, and in confined spaces to do inspection and other activities.
I am in the middle of applying to Aerospace Engineering schools right now so I don’t have much time to keep working on this until my applications are all in. I hope you like the video.