Have a look on this page, I accidentally started the thread at the wrong place, but want to keep the old posts.
http://www.multirotorforums.com/showthread.php?12124-Building-my-own-Multicopter&p=113271#post113271
http://www.multirotorforums.com/showthread.php?12124-Building-my-own-Multicopter&p=113271#post113271
