Howard wrote:

Good News Perry.....   It has been stated that duct fans generate a fairly
large proportion of their thrust from the duct itself..... I'm not at all
sure what the mechanism for this aerodynamically, but any thrust not fed
through the prop shaft is unloading the bearing.   I'm not so sure I'd be
too quick to assume that your success applies to all direct drive
installations.

    By the way.... what is the current status of your duct fan project....
Do you have a combination that is producing the projected thrust yet.....
Are you satisfied?  or do you forsee more modifications?

Perry Mick wrote:

I think I have about the optimum duct/fan combination that I've been
able to come up with in duct2/fan3.  This is the duct with a 30% venturi
(airspeed
in fan plane is 30% higher than ambient airspeed), and the carbon fiber
prop with the tapered blades.  I don't foresee anymore mods in this area.

I'm concentrating my efforts now in weight reduction and engine mods.
Just got an aluminum flywheel from Mazdatrix to get some weight out there.
This winter will make intake and exhaust mods to streamline the cowl and get
more weight out.  My speed will increase if I can get the RPM up a little
higher.

I don't cruise at full throttle because of vibration, but when I get the
rubber mount maybe I can run it a little harder.  I climb at 5100 RPM full
throttle but cruise at 4800.  Maybe one of those high energy 
spark systems would help.

A turbocharger would really perk things up too. If I put a turbocharger
on then duct3 might work better.

Maybe 2-3 years down the road when Tracy gets a few of his PSRU's out
there in the field and they show good longevity, I could see putting one of
those on at that time.  It may be like taking the training wheels off
(supposed speed increase with prop).  

Until then, I'll stay with what I've got and
try to keep improving it.  145 mph (125knots) is a lot better than what
I was flying before, and cheaper and more fun too.

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

I think the new intake manifold will clean up that cowling Perry
and should pick up some speed for you. Charley Airesman has done
wonders with his direct drive prop and a real slick cowling.
His prop tips are even thinner than yours :-)

Paul Lamar
 
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