X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4095614 for flyrotary@lancaironline.net; Mon, 25 Jan 2010 17:40:06 -0500 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id 551AA173976 for ; Tue, 26 Jan 2010 06:39:22 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 73AD7BEC131 for ; Tue, 26 Jan 2010 06:31:07 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Wedge/Oblique Duct Date: Tue, 26 Jan 2010 08:31:08 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000D_01CA9E61.E8C3E8D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100125-0, 01/25/2010), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_000D_01CA9E61.E8C3E8D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, I have been thinking about this, if I use A1V1=3DA2V2 to solve for the = inlet opening size, how do I know if the speed of air through the duct = is correct i.e. 10% for cruise and 30% for climb. Also If I use the Cessna 171 speed of approx 100 K for cruise =3D 10 K = through core, 70 knot climb and approx 20 K through core. Do I then use = the climb speed to calculate inlet air openings and attach an adjustable = louver exit OR I suppose I could do as Tracy does and calculate for = cruise and attach a spray bar. I'm still a little confused on the best approach. George ( down under) BTW it's Australia Day today - arrival of the first fleet. 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 =20 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 -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Wednesday, January 20, 2010 3:39 AM Subject: [FlyRotary] Wedge/Oblique Duct =20 =20 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. =20 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. =20 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. =20 =20 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 =20 __________ 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_000D_01CA9E61.E8C3E8D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 Ed,
I have been thinking about this, if I = use A1V1=3DA2V2=20 to solve for the inlet opening size, how do I know if the speed of air = through=20 the duct is correct i.e. 10% for cruise and 30% for climb.
 
Also If I use the Cessna 171 speed of = approx 100 K=20 for cruise =3D 10 K through core, 70 knot climb and approx 20 K through = core. Do I=20 then use the climb speed to calculate inlet air openings and attach an=20 adjustable louver exit OR I suppose I could do as Tracy does and = calculate=20 for cruise and attach a spray bar.
 
I'm still a little confused on the best = approach.
George ( down under)
BTW it's Australia Day today - arrival = of the first=20 fleet.
 

George, For = the bell=20 shaped duct, what I have read in K & W it appears they  say = the inlet=20 area should be between 0.25 =96 0.40 of the core area.  The more = slowing of=20 the air velocity that needs to be done by the diffuser before the core = that is=20 needed appears to call for lower area ratio values of Ai/Ab (area = inlet/area=20 core).  In the example plotted of an streamline duct in K&W = the chart=20 shows the area ratio was 0.40.

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 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

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

 

Ed,

If Ai is .33 Ab and .44 = Ab for the=20 wedge ducts, what's it for the bell shaped duct - is there any =  similar=20 drawing?

George ( down=20 under)

----- Original Message = -----=20

From: Ed=20 Anderson

To: Rotary motors in = aircraft=20

Sent:=20 Wednesday, January 20, 2010 3:39 = AM

Subject:=20 [FlyRotary] Wedge/Oblique Duct

 

 

George, here are two = figures=20 from K&W =96 one could be described as a =93Wedge=94 figure 12-6 = and the other=20 one a =93streamline=94 wedge figure = 12-12.

 

Always  dangerous = for me to=20 try to interpret what K&W are really saying, but from what I get = from=20 these two figures, it would appear that the =93streamline=94 wedge = permits you=20 to use a smaller inlet (Ai =3D 0.30 Ab) for the same performance = (same losses)=20 that you get with a larger opening Ai =3D 0.44 Ab for the pure = Wedge. =20 But, that is just my take on it.

 

The slight bump (where = the 64=20 deg angle is annotated) of the Streamline wedge may be to increase = the=20 boundary layer velocity to delay separation of the boundary layer =  in=20 that far corner where duct meets core.  =

 

Ed

Ed=20 Anderson

Rv-6A N494BW Rotary=20 Powered

Matthews,=20 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

 



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

--
Homepage: =20 http://www.flyrotary.com/
Archive and UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

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