X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 14 May 2006 12:28:43 -0400 Message-ID: X-Original-Return-Path: Received: from smtp109.sbc.mail.mud.yahoo.com ([68.142.198.208] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with SMTP id 1112973 for lml@lancaironline.net; Sun, 14 May 2006 12:21:49 -0400 Received-SPF: none receiver=logan.com; client-ip=68.142.198.208; envelope-from=elippse@sbcglobal.net Received: (qmail 14299 invoked from network); 14 May 2006 16:21:04 -0000 Received: from unknown (HELO Computerroom) (elippse@sbcglobal.net@75.15.122.82 with login) by smtp109.sbc.mail.mud.yahoo.com with SMTP; 14 May 2006 16:21:03 -0000 X-Original-Message-ID: <001201c67772$68315b40$527a0f4b@Computerroom> From: "Paul Lipps" X-Original-To: "Marv Kaye" Subject: Crankcase vacuum X-Original-Date: Sun, 14 May 2006 09:21:07 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000F_01C67737.BB2E05E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_000F_01C67737.BB2E05E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Auto racers have sometimes put a venturi in their exhaust connected to = the breather to induce a vacuum in the crankcase. This must be done so = as not to cause a crankcase explosion by use of one-way valves, Davey = screens, etc. Stock cars run 7000-9000 rpm, F1 cars run upwards of = 20,000 rpm. Since windage loss is a function of V^2, I'm not sure that = an engine turning 2700 rpm would see much benefit. There is also the = issue of the pressure differential across the piston. The low pressure = will aid the intake and power downstroke, but oppose the exhaust and = compression upstroke. 'Course, these are "Experimental" aircraft, what = used to be the first "E" in EAA! ------=_NextPart_000_000F_01C67737.BB2E05E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Auto racers have sometimes put a venturi in = their exhaust=20 connected to the breather to induce a vacuum in the crankcase. This must = be done=20 so as not to cause a crankcase explosion by use of one-way valves, Davey = screens, etc. Stock cars run 7000-9000 rpm, F1 cars run upwards of = 20,000 rpm.=20 Since windage loss is a function of V^2, I'm not sure that an engine = turning=20 2700 rpm would see much benefit. There is also the issue of the pressure = differential across the piston. The low pressure will aid the intake and = power downstroke, but oppose the exhaust and compression upstroke. = 'Course,=20 these are "Experimental" aircraft, what used to be the first "E" in=20 EAA!
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