Perry Mick wrote:

Assuming with more power I could get to 6000 RPM and 200 knots inside
the duct, 154 knots airspeed, the tip speed would be 982 fps, 200
knots is 338 fps, and the vector sum is 1039 fps.

Maybe I can reshape the airfoils at the tips.

Paul wrote:

What you need is real thin... less than 3% thick,  titanium blades
running at mach 1.4. with the right airfoil. This will give you a
lower disk loading, more RPM, more HP and more thrust efficiency IMHO.

Reshaping the blades is the easiest thing to try. Way less time
consuming than making yet another duct. PL

I'm starting to like this, mach 1.4, that should be good for more
than 7000 rpm with my current duct size.  The engine redlines at
7000 RPM anyway.  The titanium could be embedded in the carbon, just
at the outer few inches of the blade.

Perry J. Mick
Mick Duckt N7XR
http://www.ductedfan.com

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