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.
source/image(PrtSc): Stefano Rivellini
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.Watch the video from Stefano Rivellini:
With its top mesh installed its virtually impossible to get fingers and objects in contact with the blades.
I submitted a patent application, and it has been granted, patent #: 11,104,432. 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.//Stefano Rivellini