Flyscreen quadcopter

This is a quadcopter design that uses the folded aluminium bars from a fly screen as the arm struts.

Note that the motor mounts are designed for a spacing of 42mm diagonally between the motor mounting bolts. This is parametrically adjustable.

A bill of materials for my build is available here:
https://docs.google.com/spreadsheet/ccc?key=0Aq6iGQSKjhLXdEZ6RmtVU3BITUVkczgyS0N6aTFQbWc

Total weight is 906 grams, with a 2200mAH li-po battery. I have 400 grams of steel strapped to the bottom