X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 13 Jan 2013 17:51:41 -0500 Message-ID: X-Original-Return-Path: Received: from nm27.access.bullet.mail.mud.yahoo.com ([66.94.237.92] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTPS id 6010003 for lml@lancaironline.net; Sun, 13 Jan 2013 10:13:13 -0500 Received-SPF: neutral receiver=logan.com; client-ip=66.94.237.92; envelope-from=browncc1@verizon.net Received: from [66.94.237.127] by nm27.access.bullet.mail.mud.yahoo.com with NNFMP; 13 Jan 2013 15:12:38 -0000 Received: from [98.138.85.47] by tm2.access.bullet.mail.mud.yahoo.com with NNFMP; 13 Jan 2013 15:12:37 -0000 Received: from [127.0.0.1] by smtp104.vzn.mail.ne1.yahoo.com with NNFMP; 13 Jan 2013 15:12:37 -0000 X-Yahoo-Newman-Id: 822237.50077.bm@smtp104.vzn.mail.ne1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: VoElWYoVM1mxVW7wlT6nrZ_j5qu0qf5.LZPuqMAZha3LUY6 9gjXmdCZHgMWVPmczruaS_yIGLWp5JC8vH5TPAOcn5hd_EWNvDxJIjiRSdZo .ngNpdXMlY113.zauGus5IgWipjHGYTvNyw0oFFkp1vdE7jzfWC.nNwgfsxG hYS9gZhteLE1aRgJyBwSmxm.spMHNwWjFBdCfrIhNhxwKuZJYwQ2YoHpP8VJ RYT_J5ficPLs0blY4E2BEeE4ot_Z17N3RX1rKRuvjl15UConTQpqXRw_E5m4 NRO1WpIK4d5zJAQFTSQ473xwLKhQrTuNEWEn7Qt77owij.tjL1YxadEtpXEO yhKcua4ioSfe2ABtBYaGQ4i.aGP6nQXmbsKm0pdKYcMLGexYmT9LmSasJBOY gVHjoHi5v8sCDb8dr6IBmUuAcE44RKNlT8G8iVnUO.1JJlAirCB1yQEusaAM Dmaxyey1qxTCUIhuN9jcKPXV1u1rc2OfKwmDe7M0fdHdMkinHbgKGxW1JKzu gQNIMmwFHOJX6fznUn8yxGQiI1LfjGx8YK2wfc6dhzv_uY1qgF2lEH_re6lV qfGyaFhzyQRgtg9leQ7n53J9tKmu3eFijcYeQRA8aBcaCCvNgFaKTRGnOP3K WOlveiM31.ORZSSGbIjqhKKhuwFVYwzMzIVQZ5A-- X-Yahoo-SMTP: F49l9g6swBC0R9n8vJIbm7Tf3P8Xlmia8rHIwTlO__Ml Received: from chass-imac-2.home (browncc1@72.64.105.53 with plain) by smtp104.vzn.mail.ne1.yahoo.com with SMTP; 13 Jan 2013 07:12:37 -0800 PST From: Charles Brown Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: multipart/alternative; boundary=Apple-Mail-1--321849288 Subject: Re: [LML] Efficiency of canards, lawn darts and such X-Original-Date: Sun, 13 Jan 2013 09:12:36 -0600 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1085) --Apple-Mail-1--321849288 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Canards: probably no one has a final answer, but I found these tidbits = fascinating: 1. I heard about a config optimization study, and I believe it was a = grad student project at Stanford in the late 70s / early 80s, where the = object was to maximize range factor with a fixed structural weight. The = student set up the code and ran it, starting with a canard = configuration, and the code kept making the canard bigger and bigger, = and the wing smaller and smaller, until a conventional config was = arrived at. 2. The lift of the canard creates downwash on the wing, at the wing root = where the chord (and area) are greatest. At the same time, the canard's = tip vortices cause upload on the outboard wing, which increases bending = moments on the wing. It also makes it hard to get anywhere near an = elliptical lift distribution on the wing without resorting to twist, = cuffs, etc. So the canard's lift ain't for free. 3. At the end of the Beech Starship debacle ($500-800M spent in = development; 20-40 built; Beech buying them back and incinerating them), = Beech spokespersons said that the .85 scale Rutan prototype proved = completely worthless as a pathfinder to a full-scale machine. I've put = a link to an interesting article below. It essentially proves what Fred = says, that there's an awful lot in the details of the execution. Beech = somehow lost 90knots, 3,000lb, and $1M of unit cost in the translation = from the prototype to the full-scale bird. = http://www.ainonline.com/aviation-news/aviation-international-news/2008-07= -28/bulk-starship-fleet-headed-incinerator On Jan 13, 2013, at 1:28 AM, Frederick Moreno wrote: At OSH in the late 70's, era of the Vari-eze, we had dinner with the = late RT Jones, America's premier aerodynamicist. I asked him, "Are the = Vari-ezes fast with small HP because they are canards?" "No," he said, = "It is because they areslick." =20 --Apple-Mail-1--321849288 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Canards: probably no one has a final answer, but I = found these tidbits fascinating:

1.  I heard = about a config optimization study, and I believe it was a grad student = project at Stanford in the late 70s / early 80s, where the object was to = maximize range factor with a fixed structural weight.  The student = set up the code and ran it, starting with a canard configuration, and = the code kept making the canard bigger and bigger, and the wing smaller = and smaller, until a conventional config was arrived = at.

2. The lift of the canard creates downwash = on the wing, at the wing root where the chord (and area) are greatest. =  At the same time, the canard's tip vortices cause upload on = the outboard wing, which increases bending moments on the wing.  It = also makes it hard to get anywhere near an elliptical lift distribution = on the wing without resorting to twist, cuffs, etc.  So the = canard's lift ain't for free.

3.  At the = end of the Beech Starship debacle ($500-800M spent in development; 20-40 = built; Beech buying them back and incinerating them), Beech = spokespersons said that the .85 scale Rutan prototype proved completely = worthless as a pathfinder to a full-scale machine.  I've put a link = to an interesting article below.  It essentially proves what Fred = says, that there's an awful lot in the details of the execution. =  Beech somehow lost 90knots, 3,000lb, and $1M of unit cost in the = translation from the prototype to the full-scale = bird.



On Jan 13, 2013, at 1:28 AM, Frederick Moreno wrote:

At OSH in = the late 70's, era of the Vari-eze, we had dinner with the late RT = Jones, America's premier aerodynamicist.  I asked him, "Are the = Vari-ezes fast with small HP because they are canards?"  "No," he = said, "It is because they = areslick."
 

= --Apple-Mail-1--321849288--