Perry Mick wrote:

Paul wrote:

Perry,
The prop looks great Perry. It just looks like it has
too much pitch. I think with a new duct and a new prop
and with a smaller cowl you might be in the realm
of acceptable performance. Hang in there a while
longer.

Perhaps you can use those blades and
bond on a hub of some sort with carbon cloth
reinforcement to make a ground adjustable pitch
prop. A little more blade thickness down around the
hub should not matter much.

I would do that before I would make a new duct
or change the intake system and cowl.

Thanks for the input Paul.

For the moment, I'm just going to fly it the way it is.
The weather prediction for tomorrow morning is excellent.
I like to fly on weekday mornings because the wind is
calm, and there's nobody else out there.  I plan to go
high and stay up for an hour.

But in the meantime, I'm going to study this duct some more.
It's very curious to me that my prop analysis program shows
a max speed of around 142 knots, just looking at the prop,
no duct.  And that is also the calculated velocity of air
through the duct (110 * 1.33 = 147 knots) when my airspeed
is 110 knots.  If I had no duct I would be going 142 knots.
Just changing the shape of the duct should allow me to get
some of that speed back.

I'm saying you were right awhile back when you called my
duct a "low-speed" duct.

Perry J. Mick
Mick Duckt N7XR
http://www.mickaircraft.com/duckt.htm

 
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