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 5.2.15) with ESMTP id 3765386 for flyrotary@lancaironline.net; Mon, 20 Jul 2009 03:08:26 -0400 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 (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id 61DEB173875 for ; Mon, 20 Jul 2009 15:07:49 +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 068E5BEC024 for ; Mon, 20 Jul 2009 15:07:47 +0800 (WST) Message-ID: <96EF60004B9345B5B030A8E875B9383E@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: K&W Stream Duct Explanation Date: Mon, 20 Jul 2009 17:07:50 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01CA095C.9CADAF70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 090719-1, 07/19/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0022_01CA095C.9CADAF70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, Wedge shaped does indeed sound a lot better, yes that's what I meant. If the rad is inclined and the bell shape is distorted to accommodate = the inclined rad, it does ( to me) take on a wedge shape (of sorts). I know PL advocates this shape because of space limitations. I agree the = bell shape appears to be the optimum. George (down under) Not familiar with the Chisel or tapered description, George. I may = know it as a "wedge" type? If the Wedge type, all I can tell you is I = did quite a bit of searching trying to find some technical data on it. = The only thing I found was wedge shapes used in supersonic diffusers to = slow air down through use of shock waves (created by supersonic airflow) = for inlet to jet engines. I never found anything on it regarding = sub-sonic flow or for heat exchangers. Anything that will slow air = down, increase the pressure before the core and not cause a lot of = eddies and turbulence will probably cool. But, can't really comment on = how effective they may be compared to say the "StreamLine duct". =20 =20 Yes, the streamline duct is generally a bit too long for the size = cores we use and our cowl lengths - if you implement a full streamline = duct. That is why I have a small section in my paper on why a = truncated streamline duct might still offer some decent pressure = recovery. Since the streamline duct bell shape is not (or should not = be) larger than your core that end should not pose a problem, unless, of = course, you have your radiator canted/inclined and even then K&W = addresses that as well, although my paper does not. =20 Ed =20 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: Sunday, July 19, 2009 9:41 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: K&W Stream Duct Explanation =20 Ed, Because of insufficient room under cowl, many are using the chisel or = tapered (my name for it) shaped chamber rather than the bell shaped. To = me, it looks to be, like one side of the bell shaped chamber, or like = squeezing a bell shape down to one side. Have you studied this approach = and do you think it's comparable. George (down under) Hi Gang =20 I came across a abstraction of K&W's theory of the Streamline duct = that I put together a number of year ago. While it is my interpretation = and therefore subject to error, I have not found anything in the = intervening years that indicates a misunderstanding. While it is not = exactly light reading, I think it is easier to follow than K&W. =20 In any case, I thought I would make it available to promote = understanding and discussion {:>)) of one approach to cooling our = installations. =20 This paper targets four topic areas: =20 a.. Diffusers In General=20 b.. StreamLine Duct=20 c.. Importance of Inlet to Core area ( Ai/AB ratio)=20 d.. Truncation of StreamLine Duct=20 =20 =20 Best Regards =20 Ed =20 =20 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_0022_01CA095C.9CADAF70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed,
Wedge shaped does indeed sound a lot = better, yes=20 that's what I meant.
If the rad is inclined and the bell = shape is=20 distorted to accommodate the inclined rad, it does ( to me) take on a = wedge=20 shape (of sorts).
I know PL advocates this shape because = of space=20 limitations. I agree the bell shape appears to be the = optimum.
George (down under)

Not = familiar with the=20 Chisel or tapered description, George.  I may know it as a = =93wedge=94=20 type?    If the Wedge type, all I can tell you is I did = quite a=20 bit of searching trying to find some technical data on it.  The = only=20 thing I found was wedge shapes used in supersonic diffusers to slow = air down=20 through use of shock waves (created by supersonic airflow) for inlet = to jet=20 engines.   I never found anything on it regarding sub-sonic = flow or=20 for heat exchangers.  Anything that will slow air down, increase = the=20 pressure before the core and not cause a lot of eddies and turbulence = will=20 probably cool.  But, can=92t really comment on how effective they = may be=20 compared to say the =93StreamLine duct=94.  =

 

Yes, the = streamline=20 duct is generally a bit too long for the size cores we use and our = cowl=20 lengths =96 if you implement a full streamline duct.  That is why = I have a=20 small section in my paper  on why a truncated streamline duct = might still=20 offer some decent pressure recovery.  Since the streamline duct = bell=20 shape is not (or should not be) larger than your core that end should = not pose=20 a problem, unless, of course,  you have your radiator = canted/inclined and=20 even then K&W = addresses that as=20 well, although my paper does not.

 

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

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of George Lendich
Sent: Sunday, July 19, 2009 = 9:41=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: = K&W Stream Duct=20 Explanation

 

Ed,

Because of = insufficient room=20 under cowl, many are using the chisel or tapered (my name for = it) shaped=20 chamber rather than the bell shaped. To me, it looks to be, like = one side=20 of the bell shaped chamber, or like squeezing a bell shape down to one = side. Have you studied this approach and do you think it's=20 comparable.

George (down=20 under)

Hi=20 Gang

 

I came across a = abstraction=20 of  K&W=92s = theory of the=20 Streamline duct that I put together a number of year ago.  = While it is=20 my interpretation and therefore subject to error, I have not found = anything=20 in the intervening years that indicates a misunderstanding.  = While it=20 is not exactly light reading, I think it is easier to follow than=20 K&W.

 

In any case, I thought = I would=20 make it available to promote understanding and discussion {:>)) = of one=20 approach to cooling our installations.

 

This paper targets four topic=20 areas:

 

  • Diffusers In=20 General
  • StreamLine=20 Duct
  • Importance of=20 Inlet to Core area ( Ai/AB=20 ratio)
  • Truncation of=20 StreamLine Duct

 

 

Best=20 Regards

 

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

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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 __________

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