Efficient diy propellers + scratch built quadcopter

Just playing around with tech stuff (as ALWAYS!) I discovered that you can build
surprisingly efficient propellers from cylindrical objects, or laminated on top of one.
Flight of scratch built 1:4 scale quad at the end of the movie.


[youtube]JQmFwtc0HOw[/youtube]


Youtube channel: http://www.youtube.com/user/amazingdiyprojects

that is awesome, Dammit, Wish i had the skills to make props

[youtube]CmhwROMBK8E[/youtube]

This is cool! I would like to know how efficient they are compared to basic 2 blade propeller.