X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf18aec.mail.bellsouth.net ([205.152.59.66] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2198471 for flyrotary@lancaironline.net; Wed, 25 Jul 2007 11:31:10 -0400 Received-SPF: none receiver=logan.com; client-ip=205.152.59.66; envelope-from=rusty@radrotary.com Received: from ibm59aec.bellsouth.net ([65.6.194.9]) by imf18aec.mail.bellsouth.net with ESMTP id <20070725153031.WYXN29548.imf18aec.mail.bellsouth.net@ibm59aec.bellsouth.net> for ; Wed, 25 Jul 2007 11:30:31 -0400 Received: from rad ([65.6.194.9]) by ibm59aec.bellsouth.net with ESMTP id <20070725153031.SELG16176.ibm59aec.bellsouth.net@rad> for ; Wed, 25 Jul 2007 11:30:31 -0400 From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: Exhaust scavenging effect? Date: Wed, 25 Jul 2007 10:30:32 -0500 Message-ID: <03e901c7ced0$bd45dbe0$a301a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_03EA_01C7CEA6.D46FD3E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6822 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 Importance: Normal Thread-Index: AcfO0Lvuj1Q6P/QCRqqoKyQEOc08Cw== This is a multi-part message in MIME format. ------=_NextPart_000_03EA_01C7CEA6.D46FD3E0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Greetings, =20 With all the talk of single rotor power levels, everyone seems to be assuming that we'll get half of what a 2 rotor gets for HP. One thing = that we lose with the single rotor is the scavenging effect that can be = gained from the exhaust flow of the other rotor. How much of a HP loss is = this?=20 =20 My guess is that it won't be much of a factor, but that's only a guess. = My assumption is that there isn't a huge difference in power between having = two separate exhaust paths (Ed) vs having a perfect converging exhaust on a = two rotor. Seeing as most of us never had a perfect converging system, the = diff will be even less. Is it significant enough to think about for our purposes, where packaging is almost more important than outright performance? =20 =20 Cheers, Rusty=20 =20 =20 ------=_NextPart_000_03EA_01C7CEA6.D46FD3E0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
Greetings,
 
With all the = talk of single=20 rotor power levels, everyone seems to be assuming that we'll get = half of=20 what a 2 rotor gets for HP.   One thing that we lose with = the=20 single rotor is the scavenging effect that can be gained from the = exhaust=20 flow of the other rotor.  How much of a HP loss is=20 this? 
 
My guess is = that it won't=20 be much of a factor, but that's only a guess.  My assumption is = that there=20 isn't a huge difference in power between having two separate exhaust = paths=20 (Ed) vs having a perfect converging exhaust on a two=20 rotor.  Seeing as most of us never had a perfect converging = system,=20 the diff will be even less.  Is it significant enough to think = about=20 for our purposes, where packaging is almost more important than outright = performance? 
 
Cheers,
Rusty =
 
 
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