From Robot Dreams:
"The Shrediquette DLXm is an amazingly clean and efficent tricopter design weighing a scant 628 grams yet capable of carrying a payload of up to 550 grams in
sustained flights lasting as long as 18 minutes. It has a lift to weight
ratio of 2.87:1 and incorporates features that make it an absolute
pleasure to operate and experience (at least from the video since we
haven't had the opportunity to fly it in person, yet…).
The tricopter designer, W. Thielicke, is a PhD student and research assistant at the University of Applied Sciences, Bremen, Germany. He's generously posted the latest versions of
the project publically on his blog including the instructions and
manual, source code, PCB layout (Eagle format), configuration tool
(GUI), and PC -> PWM converters."