I´m  trying to get a quad optimized in time flight. But with some marging to transport cameras or FPV staff.

Finally I´ve got this design based in the following:

Dimensions are mid size: 40cm between motors.

- two 1mm CFRP (carbon) plates

- arms in pine wood.

- Propellers: 8x4

- board ArdupiratesNG (I´ll move to AC2 soon) with GPS and sonar

- removing of all non-strictely necesary hardware

-Total weight (with 2200 mA batery) = 650g

Images and details on motor, ESC etc are in the attached file

I´ve got a hovering flight of 17.5 min! and it flies veeery well. It hovers at about of 25% of available power.

A video flying is here: http://vimeo.com/26028981

Hope you like.

Angel