prop formula

[Jeff H. Snider]

Thanks for the feedback.  Nothing that can be done with paper
and pencil, or keyboard and cpu, replaces going into the field
and making some real world observations.  But having an
analytical brain and being a former student of Math and Physics
I really like being able to calculate my way through a problem.
Plus having a theory to support what I see happening in the
air does a world of good for my rate of improvement as a pilot.

I missed reading about Jim Woodward and his 18x10 prop.
Where was that?

About multi-blade props.  APC's website says they roughly weigh:
 17" 2 blade .07 lb
 16" 3 blade .10 lb
 15" 4 blade .46 lb!
Is that a typo?  Does a 4-blade add over 6 ounces to your
nose?  I'm ready to give this multi-blade bandwagon a test
ride, but no one is flying a half-pound prop!  Are they?

As Dean says, this is fun stuff!  I need to read up on
that guy Renard.  Anyone have a suggestion for a good book
on the subject?  I have "Model Aircraft Aerodynamics" or
something similarly titled, which gave me my first exposure
to the amount of art pervading the science of aerodynamics.
(By my calculations, at the present rate of improvement
in technology we're 120 years away from being able to use
our desktop computers for a full and complete molecule by
molecule realtime simulation of air flowing over a wing.
Maybe by then science will have more fully displaced art.)

	-Jeff
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