Comment by Ed Kirk on May 4, 2012 at 9:58am

http://vimeo.com/30682403

I have been working with counter rotating coaxial motor props for over a year, they are very smooth and stable.  I have almost completed my second project.  Bench tests on my new one produces 10 lbs thrust on just one motor set.

It flies so well I am surprised it hasn't caught on.  The biggest hastle is mounting the motors to the boom and the props are a little difficult, but worth it.

Ed

Comment by Ed Kirk on May 4, 2012 at 10:30am

My test stand and coaxial counter rotating setup for y6.  I had to modify the lower prop adapter and the mounting pads, had to get a step drill to drill out the lower prop for the 12mm hub.  I have been busy building for other folks and haven't had time to get it finished.  Soon, hopefully in the next couple of days.  This platform is for a camera and video.

Ed

Comment by IKE on May 4, 2012 at 11:37am

Co-axial props should also be more efficient for a given thrust.

Comment by arashi on May 4, 2012 at 1:22pm

Isn't the Hoover dam footage from Trappy? 

3D Robotics Comment by Alan Sanchez on May 4, 2012 at 2:00pm

arashi, looks like it

ed, looks awesome, bring it by next time youre in town.

Developer Comment by R_Lefebvre on May 5, 2012 at 5:47am

@IKE, you would think so, but apparently that's not true.  I've heard they are up to 40% less efficient.

Comment by IKE on May 5, 2012 at 6:28am

In theory they should be more efficient because a single propeller creates a rotating moment on the fluid that is wasted energy. If you can create a counter-moment from another propeller below you can transform this to thrust. Of course in order for this to work you should design and size the airfoils very carefully. Having the same kind of props top and bottom is by definition inefficient.

Comment by eduardo on May 5, 2012 at 7:45pm

ARGghhhh nice machine ... but use piezo gyros!

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