X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 5.2.2) with ESMTP id 2879978 for flyrotary@lancaironline.net; Thu, 01 May 2008 10:05:28 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m21.mx.aol.com (mail_out_v38_r9.3.) id q.c72.2f8b06b1 (29679) for ; Thu, 1 May 2008 10:04:37 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Thu, 1 May 2008 10:04:37 EDT Subject: Re: [FlyRotary] Re: Dual plugs To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1209650677" X-Mailer: 9.0 for Windows sub 5132 X-Spam-Flag: NO -------------------------------1209650677 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 5/1/2008 5:12:15 AM Pacific Daylight Time, eanderson@carolina.rr.com writes: Lynn would be the one to address what - if any - effects opening up the trailing spark plug hole would have. I must admit I would be a bit concerned about flash over into the next rotor face as its coming up on its compression stroke, but that is purely speculation on my part - don't know if it even could happen.. Ed The trailing (little hole) is there for two reasons. It helps the very long combustion chamber and allows for a very long period to burn close to all of the mixture. There are folks who drill out the trailing hole to get a faster burn going. Probably never a problem so long as the timing is moderate and idle speed is high enough. Should burning mixture cross over that drilled out hole and ignite the next chamber, the engine will not survive the event. (it shears off the top dowel) The little hole also allows for a shielded plug to survive a flooding situation, and still start the engine. The Aussies drill that hole slightly bigger, and machine a lateral groove, about 3/4" across the hole. It is alleged that this would get the better burn of the big hole without the pre-ignition danger. I can see the loss of the trailing ignition system in the lap times. The driver cannot feel the difference. The driver reporting a soft engine should he ever look at a gage, would mean a leading ignition failure, or about a 5% loss of power. The EGT goes up because slightly less fuel is burning inside the chamber, and more is burning around the probes. In either case, the loss of one system is a non event. Just like a real airplane engine but better. At aircraft RPM, the burn rates are plenty fast enough to get it all done on one plug, so the power difference for ignition problems is minimal. The bigger the timing split, the more obvious will be the loss of the leading system. None is used in racing. After about 2500 RPM, it is of little value except for emissions. Lynn E. Hanover **************Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos. (http://autos.aol.com/used?NCID=aolcmp00300000002851) -------------------------------1209650677 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 5/1/2008 5:12:15 AM Pacific Daylight Time, eanderson= @carolina.rr.com writes:

Lynn would be the one to address what - &nb= sp;if any - effects opening up the trailing spark plug hole would have= . I must admit I would be a bit concerned about flash over into the ne= xt rotor face as its coming up on its compression stroke, but that is purely= speculation on my part - don't know if it even could happen.. <= /DIV>

Ed

The trailing (little hole) is there for two reasons. It helps the very=20= long combustion chamber and allows for a very long period to burn close to a= ll of the mixture. There are folks who drill out the trailing hole to get a=20= faster burn going.

Probably never a problem so long as the timing is moderate and idle spe= ed is high enough. Should burning mixture cross over that drilled out hole a= nd ignite the next chamber, the engine will not survive the event.

(it shears off the top dowel) The little hole also allows for a shielde= d plug to survive a flooding situation, and still start the engine.

The Aussies drill that hole slightly bigger, and machine a lateral groo= ve, about 3/4" across the hole. It is alleged that this would get the better= burn of the big hole without the pre-ignition danger.

I can see the loss of the trailing ignition system in the lap times. Th= e driver cannot feel the difference. The driver reporting a soft engine shou= ld he ever look at a gage, would mean a leading ignition failure, or about a= 5% loss of power. The EGT goes up because slightly less fuel is burning ins= ide the chamber, and more is burning around the probes.

In either case, the loss of one system is a non event. Just like a real= airplane engine but better.

At aircraft RPM, the burn rates are plenty fast enough to get it all do= ne on one plug, so the power difference for ignition problems is minimal. Th= e bigger the timing split, the more obvious will be the loss of the leading=20= system. None is used in racing. After about 2500 RPM, it is of little value=20= except for emissions.

Lynn E. Hanover

Need a new r= ide? Check out the largest site for U.S. used car listings at AOL Autos.

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