[Riegerb]

Looking at this from an Aerospace Engineering perspective, the weight distribution / CG properties may significantly limit the lateral movement of this vehicle; looks as such in the videos as well. This is because in order for a helicopter to move laterally it must pitch the rotors (in this case meaning the entire body) and a cg far from the rotor location makes this difficult. Something to think about.

[mhandley]

Don't helicopters behave similar to rockets as regards CG properties? I would think the Pendulum Rocket Fallacy would apply here too: http://en.wikipedia.org/wiki/Pendulum_rocket_fallacy

In fact a large fuselage hanging down from below the rotor can cause a helicopter to become unstable. If the helicopter rolls, the rotor will slip sideways, gaining horizontal speed. The drag on the fuselage below the rotor will cause the helicopter to roll further, causing increased slip and increased horizontal speed, hences increased roll. To avoid this the rotors will have dihedral (they're angled upwards slightly). This is what gives stability.

Somewhat counterintuitively, a helicopter is actually more stable in roll if the fuselage is above the rotor, but that usually makes it hard to land safely: https://books.google.co.uk/books?id=Q27ho2szWCoC&pg=PA346#v=...

[digikata]

This application might not need that much lateral performance, and the cg as is gives you nice static stability margin where you can relax all sorts of other requirements (control loop can be slower, the nav sensors can be lower performance, it's less sensitive to wind gusts, etc).

[Riegerb]

Absolutely - I just wanted to point this out after seeing some discussion about this as a 'follow-me' type of sports filming drone.