X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtai114.cox.net ([68.230.241.46] verified) by logan.com (CommuniGate Pro SMTP 5.2.4) with ESMTP id 2995649 for flyrotary@lancaironline.net; Sat, 28 Jun 2008 14:11:19 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.46; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao103.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080628174854.JJIG1276.fed1rmmtao103.cox.net@fed1rmimpo03.cox.net> for ; Sat, 28 Jun 2008 13:48:54 -0400 Received: from BigAl ([72.192.137.74]) by fed1rmimpo03.cox.net with bizsmtp id jVpB1Z00G1cVYgg04VpBnf; Sat, 28 Jun 2008 13:49:11 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Running lean of peak Date: Sat, 28 Jun 2008 10:49:51 -0800 Message-ID: <000001c8d94f$bf7e5330$6401a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C8D90C.B15B1330" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C8D90C.B15B1330 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Bill writes: Al, something else to think about. If you run lean mixtures is you may = want to run the widest plug gap you can easily fire. The reason is that when doing lean operation studies engine manufacturers have found that a = strong spark and wide gap is best to reliably ignite lean mixtures=20 Lynn writes: Fresh plugs gapped tight. Hum-m-m; seems to be some difference of opinion. My B9EGVs are gapped = at about .025; or a few thousands over. I did some adjusting yesterday on the EGT spread. It clearly varies = with rpm, and I suspect on my setup that is primarily due to air flow = variations. I had close to 100F spread at low power (2000 rpm) which decreased with increased power. Using modes 4 & 5 on the three rotor I adjusted mixture = so the temps are within 20F at about 15.5" MAP (below staging). It required leaning 1 and 2 to get them close to #3. At WOT on the ground I then = find that rotor 2 is 50-60 hotter than the 1 and 3 which are relatively = close. I'll do some adjusting in the air at cruise conditions. AL G ------=_NextPart_000_0001_01C8D90C.B15B1330 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Bill writes:

Al, something else to think about. If you run = lean mixtures is you may want to run the widest plug gap you can easily fire. = The reason is that when doing lean operation studies engine manufacturers = have found that a strong spark and wide gap is best to reliably ignite lean = mixtures

Lynn writes:

Fresh plugs gapped tight.

Hum-m-m; seems to be some = difference of opinion.  My B9EGVs are gapped at about .025; or a few thousands = over.

I did some adjusting yesterday on = the EGT spread.  It clearly varies with rpm, and I suspect on my setup = that is primarily due to air flow variations.  I had close to 100F spread = at low power (2000 rpm) which decreased with increased power. Using modes 4 = & 5 on the three rotor I adjusted mixture so the temps are within 20F at about = 15.5” MAP (below staging). It required leaning 1 and 2 to get them close to = #3.  At WOT on the ground I then find that rotor 2 is 50-60 hotter than the 1 = and 3 which are relatively close.  I’ll do some adjusting in the = air at cruise conditions.

AL G

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