X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Received: from [64.12.137.3] (HELO imo-m22.mail.aol.com) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1919599 for flyrotary@lancaironline.net; Tue, 13 Mar 2007 19:22:32 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.3; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m22.mx.aol.com (mail_out_v38_r7.6.) id q.ce2.b8efaf6 (14502) for ; Tue, 13 Mar 2007 19:21:33 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Tue, 13 Mar 2007 19:21:33 EDT Subject: Re: [FlyRotary] Re: Engine noise and changes in timeing and mixture. To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1173828093" X-Mailer: 9.0 Security Edition for Windows sub 5359 X-Spam-Flag: NO -------------------------------1173828093 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 3/13/2007 2:24:11 P.M. Eastern Standard Time, wrjjrs@aol.com writes: Enerest, Please note I mis-typed the line and I believe the noise will increase again as the tuning improves. There are many factors here, timing, mixture and exhaust tuning. If all the other factors remain the same I have found that ported engines are usually quieter when too rich. This is anecdotal, I haven't recorded it with a DB meter. My personal explaination is that the cylinder pressures are higher when better tuned and the sudden port opening in a rotary or 2-cycle causes a louder "bark" The rotary is particularly bad in this respect. Bill Jepson The over rich rotary sounds dull and a bit less noisy, with a big fire ball on closed throttle. Over lean sounds raspy and sharp but unpleasant. Crackles on closed throttle with little or no fireball. Did anyone hear the RX-8 three rotor at the Mexico city race? Very nice sound. Down on power at 9,000 feet but won the race anyway. Lynn E. Hanover


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AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. -------------------------------1173828093 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 3/13/2007 2:24:11 P.M. Eastern Standard Time,=20 wrjjrs@aol.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DVerdana color=3D#000000 siz= e=3D2>
Enerest, Please note I mis-typed the line and I believe the noise wil= l=20 increase again as the tuning improves. There are many factors here,= =20 timing, mixture and exhaust tuning. If all the other factors remain the sa= me I=20 have found that ported engines are usually quieter when too rich. This is=20 anecdotal, I haven't recorded it with a DB meter. My personal explaination=20= is=20 that the cylinder pressures are higher when better tuned and the sudden po= rt=20 opening in a rotary or 2-cycle causes a louder "bark" The rotary is=20 particularly bad in this respect.
Bill Jepson
The over rich rotary sounds dull and a bit less noisy, with a big fire=20= ball=20 on closed throttle.
 
Over lean sounds raspy and sharp but unpleasant. Crackles on closed=20 throttle with little or no fireball.
 
Did anyone hear the RX-8 three rotor at the Mexico city race? Very nice= =20 sound. Down on power at 9,000 feet but won the race anyway.
 
Lynn E. Hanover 



AOL now offers free email to everyone. Find out more about what's free fro= m AOL at AOL= .com.
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