Hi everyone, I'm thinking about building x-ufo helicopter, and I'd like to know how strong motors I need. I've been looking for some info in the internet but didn't came across anything interesting. Can you help me and show me a book or a site where i can find some tips and infos I want to lift 2-3kg helicopter. I know that if I want my helicopter to lift it has to have greater acceleration than g = 9.8 m/s^2, if I want it to stand still motors have to produce enough power to balance the gravity. But these are the most basic laws, what next?