X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m20.mx.aol.com ([64.12.137.1] verified) by logan.com (CommuniGate Pro SMTP 4.3.4) with ESMTP id 1010258 for flyrotary@lancaironline.net; Wed, 22 Jun 2005 14:35:56 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.1; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m20.mx.aol.com (mail_out_v38_r1.7.) id q.6b.47c6b914 (15702) for ; Wed, 22 Jun 2005 14:35:05 -0400 (EDT) Received: from mblk-d39 (mblk-d39.mblk.aol.com [205.188.212.223]) by air-id05.mx.aol.com (v106.2) with ESMTP id MAILINID53-3d5642b9af591f6; Wed, 22 Jun 2005 14:35:05 -0400 Date: Wed, 22 Jun 2005 14:35:05 -0400 Message-Id: <8C745703E27253C-8D4-178A7@mblk-d39.sysops.aol.com> From: wrjjrs@aol.com References: Received: from 66.127.99.234 by mblk-d39.sysops.aol.com (205.188.212.223) with HTTP (WebMailUI); Wed, 22 Jun 2005 14:35:05 -0400 X-MB-Message-Source: WebUI X-MB-Message-Type: User In-Reply-To: X-Mailer: AOL WebMail 1.1.0.12781 Subject: Re: [FlyRotary] Re: PP debate was Re: Single PP HP? Content-Type: multipart/alternative; boundary="--------MailBlocks_8C745703E27253C_8D4_16BF6_mblk-d39.sysops.aol.com" MIME-Version: 1.0 To: flyrotary@lancaironline.net X-AOL-IP: 205.188.212.223 ----------MailBlocks_8C745703E27253C_8D4_16BF6_mblk-d39.sysops.aol.com Content-Type: text/plain; charset="us-ascii" I've ended up talking to people like Racing Beat, or Leon who have advised strongly against it for aircraft use. I believe I had that same conversation with Bruce once as well. Maybe someone can ask him again. While Lynn seems to love PP for racing, I'm not sure I've seen him state that he thinks it's the best way to go for aircraft. How about it Lynn, for, or against PP for aircraft use? I would really like to hear the logic on that one! (Why RB or Leon recomend against.) Aircraft need HP! There are two RV's flying now with the Powersport conversion. (Which is PP) Van's is doing comparison flying against the lycomings, or may have finished already. To be published in the RVator newsletter. They posted that they loved the performance. Powersports conversion is expensive, and they need to work on the radiator layout. The performance IS good however. If your timing on the PP isn't super radical you shouldn't have any idle problems. Remember all the early rotary engines were PP! One thing that I have mentioned to others about idle, you need a good SEALED system for low RPM or idle use. If you have an old V-8 with a carburator take the air filter off and check how small the openings in the carb butterflies are at idle. And that is for around 300 CI. A lot of people think you can have signifigant air leaks and "the EFI will correct for it". This is flat out WRONG. At idle a small air leak can change the available air by 20%. This can play hell with air/fuel mixtures. Lastly remenber that the Mazda LeMans engine was run durring an efficiency formula. The far trailing (3rd) plug improved the efficiency by only 2% but it was measurable. The PP will produce decent fuel economy at a 70% cruise! Don't forget that road cars only spend about 1% of their time there. Bill Jepson ----------MailBlocks_8C745703E27253C_8D4_16BF6_mblk-d39.sysops.aol.com Content-Type: text/html; charset="us-ascii"

I've ended up talking to people like Racing Beat, or Leon who have advised strongly against it for aircraft use. I believe I had that same conversation with Bruce once as well. Maybe someone can ask him again. While Lynn seems to love PP for racing, I'm not sure I've seen him state that he thinks it's the best way to go for aircraft. How about it Lynn, for, or against PP for aircraft use?

I would really like to hear the logic on that one! (Why RB or Leon recomend against.)

Aircraft need HP! There are two RV's flying now with the Powersport conversion. (Which is PP) Van's is doing comparison flying against the lycomings, or may have finished already. To be published in the RVator newsletter. They posted that they loved the performance. Powersports conversion is expensive, and they need to work on the radiator layout. The performance IS good however. If your timing on the PP isn't super radical you shouldn't have any idle problems. Remember all the early rotary engines were PP! One thing that I have mentioned to others about idle, you need a good SEALED system for low RPM or idle use. If you have an old V-8 with a carburator take the air filter off and check how small the openings in the carb butterflies are at idle. And that is for around 300 CI. A lot of people think you can have signifigant air leaks and "the EFI will correct for it". This is flat out WRONG. At idle a small air leak can change the available air by 20%. This can play hell with air/fuel mixtures. Lastly remenber that the Mazda LeMans engine was run durring an efficiency formula. The far trailing (3rd) plug improved the efficiency by only 2% but it was measurable. The PP will produce decent fuel economy at a 70% cruise! Don't forget that road cars only spend about 1% of their time there.

Bill Jepson

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