prop formula

[John Pavlick]

Jeff,
 Science displacing art? Obviously you haven't seen a good Analog Engineer
design and test an RF circuit. The only thing missing is the Dragon's Blood
and Eye of Nute. Your method of studying problems is refreshing though. I
wish some of the Engineers that I have worked with subscribed to this method
of thinking, rather than "Plug and Pray". You will be a formidable adversary
next year (I suspect that you will be flying Intermediate). If only I can
turn you to the "Dark Side"...
 I was thinking of trying a 3-blader myself. For now I just want to get
something reliable / proven to practice with. I have to re-train myself to
fly the 2 meter planes s-l-o-w-l-y. My lasting impression of Pattern comes
from watching Tipo's and Curare's with retracts and pipes. I still can't
believe these new planes don't tip stall when they're landing as slowly as
they do. I have to make a conscious effort to concentrate on a new
technique. I don't think the prop will be a major concern yet.
 As far as technology / progress goes, you might be wrong on that
calculation. Some of the things we do on desktop computers today were not
even possible on super computers a decade ago. Besides, all of this CAD CAM
stuff is nice but keep in mind that the Wright Brothers didn't have any of
this. You can't wait for technology to catch up with your creativity - come
on, get out your slide rule...

John Pavlick
http://www.idseng.com


> -----Original Message-----
> From: discussion-request at nsrca.org
> [mailto:discussion-request at nsrca.org]On Behalf Of Jeff H. Snider
> Sent: Thursday, October 21, 2004 6:18 PM
> To: discussion at nsrca.org
> Subject: Re: prop formula
>
>
> 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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