X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 711823 for flyrotary@lancaironline.net; Mon, 05 Sep 2005 13:09:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-065-188-083-049.carolina.res.rr.com [65.188.83.49]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j85H8m1v009783 for ; Mon, 5 Sep 2005 13:08:50 -0400 (EDT) Message-ID: <001101c5b23c$397ca8a0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Another great flying day = another day of troubleshooting Date: Mon, 5 Sep 2005 13:06:57 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000E_01C5B21A.B22F8640" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000E_01C5B21A.B22F8640 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Well, actually it is absolute pressure that the spark plug is reacting = to. In this example, the absolute pressure in the intake is 1.234" HG = higher at 10,000 with your 26 " boost than at sea level with your 36" of = boost.. This would contribute to an increased pressure in the = combustion chamber when it is compressed over the sea level compression = pressure. Therefore, the spark plug is facing a tougher task at 10,000 = than at Sea level (in this example). Ed ----- Original Message -----=20 From: David Leonard=20 To: Rotary motors in aircraft=20 Sent: Monday, September 05, 2005 12:57 PM Subject: [FlyRotary] Re: Another great flying day =3D another day of = troubleshooting Actually, Dave you had a higher pressure ratio (manifold to = ambient) at 10,000 feet with 26" boost than at sea level with 36". At = sea level the pressure ratio would be 36/29.92 =3D 1.20. At 10,000 ft = ambient pressure =3D 20.57 " hg , so the pressure ratio would be = 26/20.57 =3D 1.26. Not much greater, but it was higher by approx.1.23" = Hg. (1.20 -1.26 =3D .06 *20.57 =3D 1.234" Hg).=20 Ed A Right. But what does the plug know about the ambient pressure? I = thought that it was just the absolute density of the charge that was = contributing to SAG.=20 --=20 Dave Leonard Turbo Rotary RV-6 N4VY http://members.aol.com/_ht_a/rotaryroster/index.html http://members.aol.com/_ht_a/vp4skydoc/index.html ------=_NextPart_000_000E_01C5B21A.B22F8640 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Well, actually it is absolute pressure that the = spark plug=20 is reacting to.  In this example, the absolute pressure in the = intake is=20 1.234" HG higher at 10,000 with your 26 " boost than at sea level with = your 36"=20 of boost..  This would contribute to an increased pressure in the=20 combustion chamber when it is compressed over the sea level compression=20 pressure.  Therefore, the spark plug is facing a tougher task at = 10,000=20 than at Sea level (in this example).
 
Ed
----- Original Message -----
From:=20 David=20 Leonard
Sent: Monday, September 05, = 2005 12:57=20 PM
Subject: [FlyRotary] Re: = Another great=20 flying day =3D another day of troubleshooting

 Actually, Dave you had a higher pressure ratio (manifold = to=20 ambient) at 10,000 feet with 26" boost than at sea level with = 36". =20 At sea level the pressure ratio would be 36/29.92 =3D 1.20.  = At 10,000=20 ft ambient pressure =3D 20.57 " hg , so the pressure=20 ratio would  be 26/20.57 =3D 1.26.  Not = much=20 greater, but it was higher by approx.1.23" Hg. (1.20 -1.26 =3D .06 = *20.57 =3D=20 1.234" Hg).

Ed=20 A

Right.  But what does = the=20 plug know about the ambient pressure?  I thought that it was just = the=20 absolute density of the charge that was contributing to SAG. =

--=20
Dave Leonard
Turbo Rotary RV-6 N4VY
http://memb= ers.aol.com/_ht_a/rotaryroster/index.html
http://members= .aol.com/_ht_a/vp4skydoc/index.html=20 ------=_NextPart_000_000E_01C5B21A.B22F8640--