[cronix]

I'm kind of surprised they use only 4. There are drones with 6 and 8 rotors, which can still fly if 1 fails, which they use in the film industry to fly heavier, more expensive cameras. There are also ways to get quads to fly on less than 4 rotors if one becomes damaged, although as a human I'm not sure I'd want to be in one doing it. Here's a Ted Talk with a live demo from 2013: https://www.youtube.com/watch?v=w2itwFJCgFQ

[sandos]

I think its really 8 though, just pancaked on top of eachother?

[mkl]

The site says this can fly with one motor out.