X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 21 Oct 2013 07:37:25 -0400 Message-ID: X-Original-Return-Path: Received: from mail.carneal.com ([174.129.224.69] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6546991 for lml@lancaironline.net; Sat, 19 Oct 2013 08:33:38 -0400 Received-SPF: none receiver=logan.com; client-ip=174.129.224.69; envelope-from=walter@advancedpilot.com Received: (qmail 25074 invoked from network); 19 Oct 2013 12:33:10 -0000 Received: from 184-155-65-121.cpe.cableone.net (HELO ?192.168.1.6?) (walter@advancedpilot.com@184.155.65.121) by mail.carneal.com with ESMTPA; 19 Oct 2013 12:33:10 -0000 From: Walter Atkinson Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: multipart/alternative; boundary="Apple-Mail=_D129138C-D271-4412-8707-27CC72870183" Subject: Re: [LML] Hot TITs on X country leg. LIVP X-Original-Date: Sat, 19 Oct 2013 07:33:04 -0500 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <0C66D346-B816-4C3D-A0C0-D1BFD48026BF@advancedpilot.com> X-Mailer: Apple Mail (2.1283) --Apple-Mail=_D129138C-D271-4412-8707-27CC72870183 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Please do NOT lean a turbocharged aircraft in the climb below critical = altitude (or even then, in most cases.). A turbo always thinks it's at = sea level. While being full rich does aid in CHT control it is NOT = because the extra fuel cools the cylinders. It is due to the burn rate = of the richer mixture altering the thetaPP--not the heat of vaporization = of any additional fuel. Leaning to a Target EGT for a high altitude takeoff or in the climb is = for normally aspirated engines ONLY. The reason we keep a full rich mixture to to maintain the detonation = margin during the high power operation. Some year ago, a turbo-charged = aircraft was leaned during take and climb, resulting in four deaths from = the engine failure due to detonation, which destroyed a plug ceramic and = resulted in pre-ignition. Please don't lean a turbo-charged engine at full power--unless you fully = understand the issues and decide to do a LOP climb. Those work, but are = more pilot workload and as a result, we don not recommend LOP climbs fro = any but the fully knowledgeable of the issues. =20 Walter Atkinson (225) 939-7508 On Oct 18, 2013, at 8:55 AM, Robert R Pastusek wrote: Keith wrote: =20 Question about climbing "full rich". Would it not make sense to = maintain sea-level EGT's through the climb, rather than truly full rich = all the way up to 17K? As you climb higher, 'full rich' is a whole lot = richer than the mixture you had during takeoff. This is something I = learned through John Deakin's Pelican Perch articles a few years back = when I first got the Lancair. I usually 're-lean' every 1000ft or so = during my climbs to maintain around 1320 EGT. =20 Keith LNC2 N360JH =20 Keith, Leaning to maintain a power setting as you climb will work as you note. = The result is that the engine continues to produce as much heat at = altitude as it does at sea level, while the air thins and doesn=92t = carry the heat away as well. This usually results in higher CHTs and oil = temps. The reason for using =93full rich=94 during climbs=85or any high = power operation for that matter=85is to deliver extra fuel=85for = cooling=85to the cylinders. Not the most efficient use of expensive = fuel, but it has other advantages, principally that of keeping the = engine temps within limits at lower airspeeds while still delivering = sufficient power to climb. The throttle control on our Continental and = Lycoming engines (and probably others?) is designed to also deliver = extra fuel at wide open throttle (WOT)--to aid cooling. So climbing at = WOT and full rich =93wastes=94 fuel, but really helps the engine deliver = its rated service life. =20 As many have said in these pages, it=92s all about keeping the engine = temps within specified limits. As long as you can monitor and control = CHTs and oil temps on our air-cooled engines, you should be OK to lean = during climb, but if the temps start approaching the specified limits, = you need to change things. This can include increasing airspeed/cooling = air flow, reducing power, or adding more fuel--via the throttle and/or = the mixture control.=20 Hope this helps=85 Bob --Apple-Mail=_D129138C-D271-4412-8707-27CC72870183 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Please do NOT lean a turbocharged aircraft in the = climb below critical altitude (or even then, in most cases.).  A = turbo always thinks it's at sea level.  While being full rich does = aid in CHT control it is NOT because the extra fuel cools the cylinders. =  It is due to the burn rate of the richer mixture altering the = thetaPP--not the heat of vaporization of any additional = fuel.

Leaning to a Target EGT for a high altitude = takeoff or in the climb is for normally aspirated engines = ONLY.

The reason we keep a full rich mixture to = to maintain the detonation margin during the high power operation. =  Some year ago, a turbo-charged aircraft was leaned during take and = climb, resulting in four deaths from the engine failure due to = detonation, which destroyed a plug ceramic and resulted in = pre-ignition.

Please don't lean a turbo-charged = engine at full power--unless you fully understand the issues and decide = to do a LOP climb.  Those work, but are more pilot workload and as = a result, we don not recommend LOP climbs fro any but the fully = knowledgeable of the issues.
 
Walter Atkinson
<walter@advancedpilot.com><= /div>
(225) 939-7508





On Oct 18, 2013, at 8:55 = AM, Robert R Pastusek wrote:

Keith = wrote:
Question about climbing = "full rich".  Would it not make sense to maintain sea-level EGT's = through the climb, rather than truly full rich all the way up to 17K? As = you climb higher, 'full rich' is a whole lot richer than the mixture you = had during takeoff. This is something I learned through John Deakin's = Pelican Perch articles a few years back when I first got the Lancair. I = usually 're-lean' every  1000ft or so during my = climbs to maintain around 1320 EGT.
 
Keith
LNC2 N360JH
 
 
As many have said in these pages, = it=92s all about keeping the engine temps within specified limits. As = long as you can monitor and control CHTs and oil temps on our air-cooled = engines, you should be OK to lean during climb, but if the temps start = approaching the specified limits, you need to change things. This can = include increasing airspeed/cooling air flow, reducing power, or adding = more fuel--via the throttle and/or the mixture control. 

Hope this = helps=85