Mailing List flyrotary@lancaironline.net Message #49785
From: George Lendich <lendich@aanet.com.au>
Subject: Re: [FlyRotary] Wedge/Oblique Duct
Date: Thu, 21 Jan 2010 09:15:39 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Ed,
If Ai is .33 Ab and .44 Ab for the wedge ducts, what's it for the bell shaped duct - is there any  similar drawing?
George ( down under)
----- Original Message -----
Sent: Wednesday, January 20, 2010 3:39 AM
Subject: [FlyRotary] Wedge/Oblique Duct

 

George, here are two figures from K&W – one could be described as a “Wedge” figure 12-6 and the other one a “streamline” wedge figure 12-12.

 

Always  dangerous for me to try to interpret what K&W are really saying, but from what I get from these two figures, it would appear that the “streamline” wedge permits you to use a smaller inlet (Ai = 0.30 Ab) for the same performance (same losses) that you get with a larger opening Ai = 0.44 Ab for the pure Wedge.  But, that is just my take on it.

 

The slight bump (where the 64 deg angle is annotated) of the Streamline wedge may be to increase the boundary layer velocity to delay separation of the boundary layer  in that far corner where duct meets core. 

 

Ed

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

 



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