X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 25 Oct 2013 07:49:40 -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 6563745 for lml@lancaironline.net; Thu, 24 Oct 2013 20:02:30 -0400 Received-SPF: none receiver=logan.com; client-ip=174.129.224.69; envelope-from=walter@advancedpilot.com Received: (qmail 8789 invoked from network); 25 Oct 2013 00:02:10 -0000 Received: from c-75-70-32-170.hsd1.co.comcast.net (HELO ?10.0.0.3?) (walter@advancedpilot.com@75.70.32.170) by mail.carneal.com with ESMTPA; 25 Oct 2013 00:02:10 -0000 From: Walter Atkinson Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: multipart/alternative; boundary="Apple-Mail=_787C5590-9158-41BD-BB61-61E80A2793E4" Subject: Re: [LML] Leaning the IO 500 X-Original-Date: Thu, 24 Oct 2013 18:01:56 -0600 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <43653DEF-558F-4223-947E-2196B0BB496B@advancedpilot.com> X-Mailer: Apple Mail (2.1283) --Apple-Mail=_787C5590-9158-41BD-BB61-61E80A2793E4 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 George: You can download the PPT from the APS website. Best Power is 75=CB=9A ROP. It will not be slower than 50dF ROP. I = suspect something is amiss in your method or measure. The TAS difference = between that and 50dF ROP will be very hard to measure--maybe a knot. = Best economy mixture changes depending on the power setting. At 60%, = it's around 10dF LOP. At 85% power, it's about 80-90dF LOP with = straight line interpolation possible. In the example you presented, the optimal LOP mixture would be about = 15dF LOP. You are not hurting anything, but have leaned further than = optimal and are giving up performance when LOP. The difference between Best Power and best economy at 7k feet (NA leaned = optimally) would be about 3 gph for a 3 knot loss in IAS. BTW, 50dF ROP and 50dF LOP should be the same number. Yours were close. = The difference was probably in finding peak form the rich and lean = sides. The fact that you noted a 9 knots difference is proof that the = LOP mixture was leaner than optimal. The 40dF diff in CHT is as = expected. You notice that 100=CB=9A ROP was the same speed as 50=CB=9A ROP is = correct. They should be so close to the same as to be essentially = immeasurable in flight! Walter Atkinson (225) 939-7508 On Oct 24, 2013, at 10:47 AM, George Wehrung wrote: Does anyone have a copy of the powerpoint presentation from the advanced = pilot seminar? I ask because I think for our plane running 50=CB=9A ROP = gives us the best performance. 50=CB=9A LOP is the best fuel economy. I have been collecting data especially on my cross country trip for our = IO 550. Basically at 7,000 feet I found that at 50=CB=9A LOP I was indicating = 170 KTS TAS and 150 KIAS. At 50=CB=9A ROP I was 179 TAS and 158 KIAS. =20 My EGTs/CHTs: 291/1435 LOP & 330/1431 ROP. When I tried 75=CB=9A ROP I slowed a couple of knots. At 100=CB=9A was = increased fuel consumption for no gain in airspeed. Anyhow, I pasted some data below which was typical for the 9 leg trip = across the US last week for our ferry flight. Also note, the plane is = not painted, which may bear differences for our ES vs others. 7000 2400 150 170 12.7 291 1435 50=CB=9A LOP 7000 2400 158 179 16.6 330 1431 50=CB=9A ROP 7000 2400 157 177 16.8 332 1416 75=CB=9A ROP 7000 2400 157 177 17.3 331 1391 100=CB=9A ROP --Apple-Mail=_787C5590-9158-41BD-BB61-61E80A2793E4 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8

Walter Atkinson

<walter@advancedpilot.com><= /div>

(225) 939-7508

On Oct 24, 2013, at 10:47 = AM, George Wehrung wrote:

Does anyone have a copy of the powerpoint = presentation from the advanced pilot seminar? I ask because I = think for our plane running 50=CB=9A ROP gives us the best performance. = 50=CB=9A LOP is the best fuel economy.

I have = been collecting data especially on my cross country trip for our IO = 550.

Basically at 7,000 feet I found that at = 50=CB=9A LOP I was indicating 170 KTS TAS and 150 = KIAS.

At 50=CB=9A ROP I was 179 TAS and 158 = KIAS.

My EGTs/CHTs: 291/1435 LOP = & 330/1431 ROP.

When I tried 75=CB=9A ROP I = slowed a couple of knots. At 100=CB=9A was increased fuel = consumption for no gain in airspeed.

Anyhow, I = pasted some data below which was typical for the 9 leg trip across the = US last week for our ferry flight. Also note, the plane is not = painted, which may bear differences for our ES vs = others.

7000	2400	150	170	12.7	291	1435	50=CB=9A LOP
7000	2400	158	179	16.6	330	1431	50=CB=9A ROP
7000	2400	157	177	16.8	332	1416	75=CB=9A ROP
7000	2400	157	177	17.3	331	1391	100=CB=9A ROP

= --Apple-Mail=_787C5590-9158-41BD-BB61-61E80A2793E4--