X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from QMTA03.westchester.pa.mail.comcast.net ([76.96.62.32] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3482031 for flyrotary@lancaironline.net; Sat, 07 Feb 2009 18:42:07 -0500 Received-SPF: none receiver=logan.com; client-ip=76.96.62.32; envelope-from=gregw@onestopdesign.biz Received: from OMTA05.westchester.pa.mail.comcast.net ([76.96.62.43]) by QMTA03.westchester.pa.mail.comcast.net with comcast id DAJB1b0050vyq2s53BhZbE; Sat, 07 Feb 2009 23:41:33 +0000 Received: from osd1 ([24.6.40.29]) by OMTA05.westchester.pa.mail.comcast.net with comcast id DBhE1b0020dkeQQ3RBhE5P; Sat, 07 Feb 2009 23:41:15 +0000 Message-ID: <43B34672810F46C58706166B32A744D2@yosemite.onestopdesign.biz> From: "Greg Ward" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Bernulli's Principle Date: Sat, 7 Feb 2009 15:43:36 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B9_01C9893A.D6EDD8B0" 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 This is a multi-part message in MIME format. ------=_NextPart_000_00B9_01C9893A.D6EDD8B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It's Bernoulli.......(:-) Greg Ward ----- Original Message -----=20 From: Lynn Hanover=20 To: Rotary motors in aircraft=20 Sent: Saturday, February 07, 2009 3:32 PM Subject: [FlyRotary] Bernulli's Principle I invite you to the Bernulli Principle web site. =20 http://home.earthlink.net/~mmc1919/venturi.html =20 =20 I did some shapes to play with in the attachment.=20 =20 Leave the reverse cone at the right end to replicate the port into the = chamber. Note a little yellow sign pop on when flow slows too fast and = separates.=20 =20 This would be at the bowl shape where the flow makes the 180 turn into = the chamber. This area is too big volume wise and costs power. Some = racers fill this in slightly to eliminate this problem. The lack of this = feature in the periphery port engine makes a huge difference, in that = velocity is carried right into the chamber, rather than slowing.=20 =20 Although not practical the ideal shape is probably a long tapered = runner. So velocity rate of increase is a constant value.=20 =20 Imagine that the mixture is a sausage, and you want the biggest piece = of sausage cut off by each rotor face.=20 The highest possible velocity is important for that. However the high = velocity creates the highest drag over a long distance.=20 =20 Two 44MM chokes in a Weber is enough for 310 HP at 10,300 RPM from a = 12A. The TB size need not be the runner size. My engine with a = bridgeport gets 250 HP at 9,400 RPM from two 38MM chokes.=20 Short runners for high RPM. Long runners for low RPM. Big runners slow velocity and ruin low speed performance with big thin = pieces of sausage. Small runners give crisp low speed performance with = smaller, longer pieces of sausage. =20 Now you won't sleep tonight either. =20 Lynn E. Hanover=20 =20 -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_00B9_01C9893A.D6EDD8B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
It's = Bernoulli.......(:-)
Greg Ward
----- Original Message -----
From:=20 Lynn=20 Hanover
Sent: Saturday, February 07, = 2009 3:32=20 PM
Subject: [FlyRotary] Bernulli's = Principle

I invite you to the Bernulli Principle web site.
 
http://home.eart= hlink.net/~mmc1919/venturi.html
 
 
I=20 did some shapes to play with in the attachment.
 
Leave = the=20 reverse cone at the right end to replicate the port into the chamber. = Note a=20 little yellow sign pop on when flow slows too fast and separates.=20
 
This would be at the bowl shape where the flow makes the = 180=20 turn into the chamber. This area is too big volume wise and costs = power. Some=20 racers fill this in slightly to eliminate this problem. The lack of = this=20 feature in the periphery port engine makes a huge difference, in that = velocity=20 is carried right into the chamber, rather than slowing. =
 
Although=20 not practical the ideal shape is probably a long tapered runner. So = velocity=20 rate of increase is a constant value.
 
Imagine that the = mixture=20 is a sausage, and you want the biggest piece of sausage cut off by = each rotor=20 face.
The highest possible velocity is important for that. However = the=20 high velocity creates the highest drag over a long distance. =
 
Two=20 44MM chokes in a Weber is enough for 310 HP at 10,300 RPM from a 12A. = The TB=20 size need not be the runner size. My engine with a bridgeport = gets 250 HP=20 at 9,400 RPM from two 38MM chokes.
 
Short runners for high RPM. Long runners for low RPM.
 
Big runners slow velocity and ruin low speed performance with big = thin pieces of sausage. Small runners give crisp low speed = performance=20 with smaller, longer pieces of sausage.
 
Now you won't = sleep=20 tonight either.
 
Lynn E. Hanover
 

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