X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4551346 for flyrotary@lancaironline.net; Mon, 01 Nov 2010 21:35:23 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao102.cox.net (InterMail vM.8.01.03.00 201-2260-125-20100507) with ESMTP id <20101102013441.ZQCX21172.fed1rmmtao102.cox.net@fed1rmimpo03.cox.net> for ; Mon, 1 Nov 2010 21:34:41 -0400 Received: from BigAl ([72.199.216.236]) by fed1rmimpo03.cox.net with bizsmtp id S1ah1f00156cS2o041ahLV; Mon, 01 Nov 2010 21:34:41 -0400 X-VR-Score: -100.00 X-Authority-Analysis: v=1.1 cv=dbaSwxnuHrR0yVADEcRPA4YIn3BZCWHRWI2DPCFObtA= c=1 sm=1 a=lN8H/RjlhkCyIsyuOn2r7w==:17 a=kviXuzpPAAAA:8 a=J_tA-pCEDhvL3MSnjH0A:9 a=pdBlEttEVMKLPdiQqfWQ3cNod_wA:4 a=CjuIK1q_8ugA:10 a=4vB-4DCPJfMA:10 a=y5dSj3KBCJNLScXFQoYA:9 a=tSptLmjq3FxNR1kprXAA:7 a=OtnrtRBKGpYhVb09AyC39yAppcsA:4 a=lN8H/RjlhkCyIsyuOn2r7w==:117 X-CM-Score: 0.00 Authentication-Results: cox.net; none From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: EM2 Numbers Date: Mon, 1 Nov 2010 18:36:21 -0800 Message-ID: <1BE53C706D714A4EAF688B3AF9F724A5@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0013_01CB79F3.AECA79F0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6863 Importance: Normal Thread-Index: Act6Ht8NzmknvlgWTSyq0HyUatgKpwAFXcKw X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5994 In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0013_01CB79F3.AECA79F0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 No, we sure didn't. In fact, I like going faster than my wallet can = keep up.=20 Yeah; me too:-) =20 In doing some searching for LDmax for the Lancair ES, I read the = statement that best economy would be the same as best glide. That makes sense to = me. Probably close enough for our purposes. What say you? =20 I found my data. I think it may be just a bit more complicated. Best = glide will likely give you the lowest fuel burn rate (gph); but since you're = going fewer miles in an hour; it's not the best mpg. My best glide speed is = about 90 kts; but my best mpg is about 130kts - quite flat from about 140 - = 120 kts. The burn rate was continuing to go down at 110 kts; which was as = far as I took data. =20 So minimum trip cost is at max MPG; if you consider your time as free. = But my plane seems to have a 'sweet' spot at 5500-5700 rpm, and at 10,500 I = can go about 170 KTAS at a tad over 10 gph, so that's what I do. I could = slow to 130 Kts and burn a tad under 7.0 gph; but would I be happy:-)? =20 Al =20 Mark On Mon, Nov 1, 2010 at 5:53 PM, Al Gietzen wrote: Where does one find the "most efficient operationg point" for a = particular airframe? Is this the same as LDmax? =20 Mark; =20 The EM2 reads out MPG. Most efficient operation would be where you get = the highest MPG. So go fly at 100F, or so; lean of peak EGT and take some = data of MPG and speed. You'll find a max MPG point that is slower than = you'll typically want to fly. I think for my Velocity it was a fairly broad = peak around 125 (I don't even remember now if that was MPH or Kts; because I never fly there in level flight). We didn't build sleek airplanes with = more powerful engines to go the speed of a Skyhawk - did we? =20 Al =20 ------=_NextPart_000_0013_01CB79F3.AECA79F0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

No, we sure didn't. In fact, I like = going faster than my wallet can keep up.

Yeah; me tooJ

In doing some searching for LDmax for the = Lancair ES, I read the statement that best economy would be the same as best glide. That makes sense to me. Probably close enough for our = purposes. What say you?

I found my data. I think it = may be just a bit more complicated. Best glide will likely give you the lowest = fuel burn rate (gph); but since you’re going fewer miles in an hour; = it’s not the best mpg. My best glide speed is about 90 kts; but my best = mpg is about 130kts - quite flat from about 140 – 120 kts. The burn = rate was continuing to go down at 110 kts; which was as far as I took = data.

So minimum trip cost is at max = MPG; if you consider your time as free. But my plane seems to have a = ‘sweet’ spot at 5500-5700 rpm, and at 10,500 I can go about 170 KTAS at a tad = over 10 gph, so that’s what I do. I could slow to 130 Kts and burn a tad = under 7.0 gph; but would I be happyJ?

Al

Mark

On Mon, Nov 1, 2010 at 5:53 PM, = Al Gietzen <ALVentures@cox.net> wrote:

Where does one find the "most efficient operationg point" for a particular airframe? Is this the same as LDmax?

Mark;

The EM2 reads out MPG. Most efficient operation would be where you get the = highest MPG. So go fly at 100F, or so; lean of peak EGT and take some data of = MPG and speed. You’ll find a max MPG point that is slower than = you’ll typically want to fly. I think for my Velocity it was a fairly = broad peak around 125 (I don’t even remember now if that was MPH or Kts; = because I never fly there in level flight). We didn’t build sleek = airplanes with more powerful engines to go the speed of a Skyhawk – did = we?

Al

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