Can the Coandă Effect Be Used to Make a Hovercraft Float?

The Coandă effect is well proven and a simple fact of aerodynamics, but it is virtually never used in actual aircraft outside of a few experimental designs. The Coandă effect describes the tendency of flowing fluids to cling to curved surfaces as they move across them. Because air is a fluid, aircraft can theoretically utilize the Coandă effect to redirect air and generate lift. But it isn’t quite so simple in the real world, and YouTuber Tom Stanton wanted to find out if it is possible to make a hovercraft float using the Coandă effect.

A conventional hovercraft is actually quite simple. Underneath the hovercraft, there is a chamber the size of the entire hull that is filled with air. A high volume of additional air is constantly being pumped into that chamber. As the air escapes—usually through a flexible curtain to maintain a smaller gap—it create a cushion on which the hovercraft floats. Stanton’s 3D-printed Coandă effect hovercraft doesn’t utilize that under-hull positive air chamber at all, and instead redirects air from the top of the craft, around the sides, and down against the ground.

Stanton had previously tested the Coandă effect on a drone, and found it to be incredibly inefficient and impractical for flight. But he did notice that his Coandă effect drone performed much better when it was close to the ground, and that was thanks to the ground effect that all aircraft are subject to. This Coandă effect hovercraft takes advantage of that to generate just enough lift to keep the hull right above the ground. Essentially, it’s directing air from around the craft and underneath to create a cushion to float on, as opposed directing air from underneath and out like a normal hovercraft. It’s unlikely that this is as efficient as a traditional hovercraft, and probably doesn’t have any advantages at all. But it’s still an interesting exploration of what can be done with the Coandă effect.