X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 30 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 21 Mar 2007 18:22:12 -0400 Message-ID: X-Original-Return-Path: Received: from ironport5.liveoakmail.com ([216.110.12.21] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1935345 for lml@lancaironline.net; Wed, 21 Mar 2007 16:33:24 -0400 Received-SPF: none receiver=logan.com; client-ip=216.110.12.21; envelope-from=walter@advancedpilot.com Received: from rs5.liveoakhosting.com (HELO secure5.liveoakhosting.com) ([64.49.254.21]) by ironport5.liveoakmail.com with ESMTP; 21 Mar 2007 15:32:37 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgAAAKQyAUZAMf4VeWdsb2JhbACDBYwdAQEJDio X-IronPort-AV: i="4.14,309,1170655200"; d="scan'208,217"; a="6756744:sNHT52864637" Received: (qmail 32429 invoked from network); 21 Mar 2007 15:32:36 -0500 Received: from 216-107-97-170.wan.networktel.net (HELO ?10.0.1.3?) (216.107.97.170) by rs5.liveoakhosting.com with (AES128-SHA encrypted) SMTP; 21 Mar 2007 15:32:36 -0500 Mime-Version: 1.0 (Apple Message framework v752.3) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-3-780927170 X-Original-Message-Id: From: Walter Atkinson Subject: Re: [LML] Re: carbureted lean-of-peak X-Original-Date: Wed, 21 Mar 2007 15:32:19 -0500 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.3) --Apple-Mail-3-780927170 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=WINDOWS-1252; delsp=yes; format=flowed Kevin: That is terribly sad. It is obvious that whoever came up with those procedures has no =20 understanding of F:A ratios, GAMI Spread, or the value of EGT. There =20= is so much wrong in that short document that it's pointless to =20 discuss it in detail. Briefly, to wit: 1) Raw EGT value is meaningless in determining F:A ratio balance. =20 Meaningless. FF is what matters. 2) The coolest EGT at peak has nothing whatsoever to do with a =20 cylinder being critical. 3) There is nothing magical about 65% power. 4) The suggestion that 100dF ROP at high power settings is optimal is =20= not in harmony with any of the known science, from any source, =20 including Lycoming. 5) Running ROP without an engine monitor is much riskier than running =20= LOP without one. They've got that backwards. Basically, this is a very embarrassingly erroneous document. =20 Performance Engines should be mortified at their poor level of =20 understanding of engine management issues. Walter On Mar 21, 2007, at 2:50 PM, Kevin Kossi wrote: This is what I have from Performance Engines: How to lean a High Performance Engine by: Performance Engines. Climb out full rich, full power to 6,000 feet (make sure all engine =20 parameters are within the correct temperature tolerances). Make sure you select a somewhat desolate area. (So you do not have to =20= worry about traffic that much). Preferably pick a day with little wind at your altitude. Engage your autopilot on a heading. Set up for 65% or less power. Suggest: 2400 rpm at 24=94 Make sure you keep a log of all this. A. Select Cylinder #1 EGT on your engine analyzer. B. Cut the mixture back one turn at a time and WAIT until the EGT =20 raises to a stabilized temperature (do not continue leaning until the temperature is =20 stabilized). The EGT will rise and subsequently stabilize with each turn of cut back on the mixture. C. Continue to cut back the mixture as stated in paragraph B until =20 you see the EGT stop climbing and start to drop. D. Immediately note the highest temperature attainable and =20 corresponding fuel flow at which Cylinder 1 stopped climbing and started descending. This cylinder has =20= reached its highest temperature attainable (PEAK EGT). E. Go to full rich. F. Select EGT cylinder #2. G. Wait for a stabilized temperature on your EGT cylinder #2. H. Repeat paragraphs A through E. on cylinders 2, 3, 4, 5, and 6. Now you have established the PEAK EGT for each cylinder. Each =20 aircraft will vary, especially experimentals. Now select the cylinder that peaked at the lowest temperature. This =20 is the CRITICAL cylinder. Let=92s suppose (and this is only a supposition) that the cylinder that =20= peaked at the lowest temperature was cylinder #5 at 1375o degrees F. This means: A. Your critical cylinder is #5, and.. B. For any cruise power setting (up to 75%) the EGT should be 100o F =20 cool of this critical cylinders peak EGT. Given the aforementioned all other cylinders will be richer =20= and therefore within a safe operating margin. C. For any higher power setting (i.e. take off), the EGT should be =20 150o to 200o degrees F. richer (cooler) of peak than established for the critical cylinder. If your =20 engine=92s set up can not achieve these temperatures you will have to change the fuel flow. By adhering to these policies you can extend the TBO of your engine. Performance Engines does not recommend running your engine lean of =20 peak (LOP) if the power setting is above 65% power. Furthermore, running LOP in excess of 65% =20= will void your warranty. (Lycoming engines may not be operated lean of peak per the =20 manufacturers=92 recommendations.). Please remember that to run lean of peak your aircraft must be =20 equipped with an engine analyzer that has downloading capability. Operation of a Performance Engine lean of peak without a downloadable =20= engine analyzer will void your warranty. Kevin Kossi Legacy 76% New York Continental IO-550-EXP 10:1 Single Lightspeed Single Slick Mag Hartzell HC-H3YF-2UFX/FC7391D-3X. Full feathering, counterweighted, 3 blade --Apple-Mail-3-780927170 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=WINDOWS-1252 Kevin:

That is terribly = sad.

It is = obvious that whoever came up with those procedures has no understanding = of F:A ratios, GAMI Spread, or the value of EGT.=A0 There is so much = wrong in that short document that it's pointless to discuss it in = detail.=A0 Briefly, to wit:

1) Raw EGT value is = meaningless in determining F:A ratio balance.=A0 Meaningless.=A0 FF is = what matters.

2) The coolest EGT at peak = has nothing whatsoever to do with a cylinder being = critical.

3) = There is nothing magical about 65% power.

4) The suggestion that = 100dF ROP at high power settings is optimal is not in harmony with any = of the known science, from any source, including Lycoming.

5) Running ROP without an = engine monitor is much riskier than running LOP without one.=A0 They've = got that backwards.

Basically, this is a very = embarrassingly erroneous document.=A0 =A0Performance Engines should be = mortified at their poor level of understanding of engine management = issues.

Walter



On Mar 21, = 2007, at 2:50 PM, Kevin Kossi wrote:

This is what I = have from=A0Performance Engines:

How to lean a High Performance Engine by: Performance = Engines.
Climb out full = rich, full power to 6,000 feet (make sure all engine parameters are = within the
correct = temperature tolerances).
Make sure you = select a somewhat desolate area. (So you do not have to worry about = traffic
that = much).
Preferably pick = a day with little wind at your altitude.
Engage your autopilot on a = heading.
Set up for 65% = or less power. Suggest: 2400 rpm at 24=94
Make sure you keep a log of all = this.
A. Select = Cylinder #1 EGT on your engine analyzer.
B. Cut the mixture back one turn at a time and WAIT until the = EGT raises to a stabilized
temperature (do not continue leaning until the temperature is = stabilized). The EGT will rise and
subsequently stabilize with each turn of cut back on the = mixture.
C. Continue to = cut back the mixture as stated in paragraph B until you see the EGT = stop
climbing and = start to drop.
D. Immediately = note the highest temperature attainable and corresponding fuel flow at = which
Cylinder 1 = stopped climbing and started descending. This cylinder has reached its = highest
temperature = attainable (PEAK EGT).
E. Go to full = rich.
F. Select EGT = cylinder #2.
G. Wait for a = stabilized temperature on your EGT cylinder = #2.
H. Repeat = paragraphs A through E. on cylinders 2, 3, 4, 5, and = 6.
Now you have = established the PEAK EGT for each cylinder. Each aircraft will vary, = especially
experimentals.
Now select the = cylinder that peaked at the lowest temperature. This is the = CRITICAL cylinder.
Let=92s suppose = (and this is only a supposition) that the = cylinder that peaked at the lowest
temperature was cylinder #5 at 1375o = degrees F.
This = means:
A. Your = critical cylinder is #5, and..
B. For any cruise power setting (up to 75%) the EGT should be = 100o F cool of this critical = cylinders
peak EGT. Given = the aforementioned all other cylinders will be richer and therefore = within a safe
operating = margin.
C. For any = higher power setting (i.e. take off), the EGT should be = 150o to 200o = degrees F. richer
(cooler) of peak than established for the critical cylinder. = If your engine=92s set up can not
achieve these temperatures you will have to change the fuel = flow.
By adhering to = these policies you can extend the TBO of your = engine.
Performance = Engines does not recommend running your engine lean of peak (LOP) if the = power
setting is = above 65% power. Furthermore, running LOP in excess of 65% will void = your warranty.
(Lycoming = engines may not be operated lean of peak per the = manufacturers=92
recommendations.).
Please remember that to run lean of peak your aircraft must be = equipped with an engine
analyzer that = has downloading capability.
Operation of a Performance Engine lean of peak without a = downloadable engine analyzer will
void your warranty.

Kevin = Kossi
Legacy=A076%
New = York=A0
Continental IO-550-EXP
10:1=A0Single = Lightspeed=A0Single Slick Mag
Hartzell=A0 Full feathering, counterweighted, 3 = blade=A0



 =


= --Apple-Mail-3-780927170--