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2 Vs 3 blade

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pitts_pilot(at)bellsouth.
Guest

Posted: Sat Apr 26, 2008 3:56 pm Post subject: 2 Vs 3 blade

I tried the archives but no joy.  Is there any side-by-side in-the-air 

data available on the 2 or 3 blade props???  I seem to recall some 

comments about efficiency ..... but don't recall the facts (if there are 

any) or which way the discussion went.



Any takers???



Linn ...... decision looming

do not archive

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rv10builder(at)verizon.ne
Guest

Posted: Sat Apr 26, 2008 6:23 pm Post subject: 2 Vs 3 blade

Pascal



--------------------------------------------------

From: "linn Walters" <pitts_pilot(at)bellsouth.net>

Sent: Saturday, April 26, 2008 4:54 PM

To: "RV-10" <rv10-list(at)matronics.com>

Subject: 2 Vs 3 blade



 	  Quote: 	
		   

 

 I tried the archives but no joy.  Is there any side-by-side in-the-air 

 data available on the 2 or 3 blade props???  I seem to recall some 

 comments about efficiency ..... but don't recall the facts (if there are 

 any) or which way the discussion went.

 

 Any takers???

 

 Linn ...... decision looming

 do not archive

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dc71(at)netspace.net.au
Guest

Posted: Sat Apr 26, 2008 6:27 pm Post subject: 2 Vs 3 blade

Comparison published in the RVator - 5th issue 2005. I've attached the  

relevant pages.



Indran



On 27/04/2008, at 7:54 AM, linn Walters wrote:



 	  Quote: 	
		   

 >



 I tried the archives but no joy.  Is there any side-by-side in-the- 

 air data available on the 2 or 3 blade props???  I seem to recall  

 some comments about efficiency ..... but don't recall the facts (if  

 there are any) or which way the discussion went.



 Any takers???



 Linn ...... decision looming

 do not archive

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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RVator5-05p6-8.pdf

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3edcft6(at)cox.net
Guest

Posted: Sun Apr 27, 2008 10:45 am Post subject: 2 Vs 3 blade

linn Walters wrote:

 	  Quote: 	
		   I tried the archives but no joy.  Is there any side-by-side in-the-air 

 data available on the 2 or 3 blade props???  I seem to recall some 

 comments about efficiency ..... but don't recall the facts (if there 

 are any) or which way the discussion went.




	




I can't site the source but it is from a report done by NASA that 

determined that a perfect 3 blade is "slightly" less efficient than a 

perfect 2 blade.  However in practice, other variables, such as engine, 

airframe, altitude, cruise speed, etc, will have more of an effect than 

the theoretical difference in efficiency between a 2 and 3 blade prop.  

With all the variables beyond our control it is very difficult to 

determine what prop would work the best for any given situation by 

comparing various reports from various builders.  What I would really 

like to see is Van's (or anybody else for that matter) build 2 identical 

planes.  Do side by side flight tests to see how close they are in the 

air for a base line.  Then start testing various changes in side by side 

tests.  Seems to me that is the best way to get data that is very useful.

do not archive



-- 

Chris W

KE5GIX



"Protect your digital freedom and privacy, eliminate DRM, 

learn more at http://www.defectivebydesign.org/what_is_drm"



Ham Radio Repeater Database.

http://hrrdb.com

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lessdragprod(at)aol.com
Guest

Posted: Sun Apr 27, 2008 11:23 am Post subject: 2 Vs 3 blade

Why build two RV-10s?  When we could fly two different propellers on the same RV-10.

 

 IMHO, it will take more time to get the flight test data than it will take to change the propellers.

 

 Regards,

 Jim Ayers

 

 --

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