X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.122] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4090749 for flyrotary@lancaironline.net; Thu, 21 Jan 2010 11:17:59 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.122; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.0 c=1 a=WbNVUdcZcaUA:10 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=nUuTZ29dAAAA:8 a=EuLgvax9ntymATGvM-MA:9 a=Zjr1U7VeuDkvEP5gy7wA:7 a=THvArcWtHR7Iu8dU-c9he48ii4AA:4 a=5zrLeAV0Z70A:10 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=SSmOFEACAAAA:8 a=2OSisXgjDw7Hr0SOdi8A:9 a=cEFjo4Nt0_rGoYmyarQA:7 a=dJMWuEjYFMImT7V-RY-6lcEsLdoA:4 X-Cloudmark-Score: 0 X-Originating-IP: 75.191.186.236 Received: from [75.191.186.236] ([75.191.186.236:2447] helo=computername) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id D7/C1-01403-21E785B4; Thu, 21 Jan 2010 16:17:23 +0000 From: "Ed Anderson" Message-ID: To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Wedge/Oblique Duct Date: Thu, 21 Jan 2010 11:17:45 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0069_01CA9A8B.5B711630" X-Mailer: Microsoft Office Outlook, Build 11.0.5510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 In-Reply-To: Thread-Index: AcqaJpOl26OrHI92T9ihrvX6wOUd1QAjFMQA This is a multi-part message in MIME format. ------=_NextPart_000_0069_01CA9A8B.5B711630 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit George, For the bell shaped duct, what I have read in K & W it appears they say the inlet area should be between 0.25 - 0.40 of the core area. The more slowing of the air velocity that needs to be done by the diffuser before the core that is needed appears to call for lower area ratio values of Ai/Ab (area inlet/area core). In the example plotted of an streamline duct in K&W the chart shows the area ratio was 0.40. 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 _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich Sent: Wednesday, January 20, 2010 6:16 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Wedge/Oblique Duct 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 ----- From: Ed Anderson To: Rotary motors in aircraft 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 __________ Information from ESET NOD32 Antivirus, version of virus signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com _____ -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html __________ Information from ESET NOD32 Antivirus, version of virus signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0069_01CA9A8B.5B711630 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

George, For the bell shaped duct, = what I have read in K & W it appears they  say the inlet area should = be between 0.25 – 0.40 of the core area.  The more slowing of = the air velocity that needs to be done by the diffuser before the core that is = needed appears to call for lower area ratio values of Ai/Ab (area inlet/area = core).  In the example plotted of an streamline duct in K&W the chart shows = the area ratio was 0.40.

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich
Sent: Wednesday, January = 20, 2010 6:16 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Wedge/Oblique Duct

 

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 ----- =

From: Ed Anderson

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 =3D 0.30 Ab) for the same performance (same losses) that you = get with a larger opening Ai =3D 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.r= otaryaviation.com/Rotorhead%20Truth.htm

 



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