X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 10 Sep 2009 06:12:19 -0400 Message-ID: X-Original-Return-Path: Received: from web53706.mail.re2.yahoo.com ([206.190.37.27] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with SMTP id 3843839 for lml@lancaironline.net; Wed, 09 Sep 2009 22:05:06 -0400 Received-SPF: none receiver=logan.com; client-ip=206.190.37.27; envelope-from=kyrilian_av@yahoo.com Received: (qmail 21494 invoked by uid 60001); 10 Sep 2009 02:04:34 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding; b=hKsOx43gSBs1anGwD8fnKcRut0hYnMP2nUN+6M+Ipkd0cqITbwnX/BmDLkyPPijXGWNiHy88t/Jia2UPURlvzUXEdJ1/a0EnmSvHWCDaC7pSvz7ELqaQKR/r+4TBTRwXzxc/MVGJnjUKrVDijAaxdjJQORkWirT84o0uQRGHTW4=; X-Original-Message-ID: <722456.17644.qm@web53706.mail.re2.yahoo.com> X-YMail-OSG: NlzBXwgVM1mvQXjGy7t7fkoORI8JBN0PUVLk2y55coAXWnbwgYAWRsKBehWsujmzsk79kpjQgAhMIXe.97r_7OGe_osv.FHCGuAHUAxgPQEeGAMOQfChBSNP1O5YMNZ1w6H8Uzkkd1y8mCEiclvWS1s805BIUFVc9Ybgxt.CiiFgIUJYx9GHXBniLznUmcTRUNF82v.IPJAILC2FnkRfhEjarTss6CJ5Wed2aWAGB2a4N3e1XRcaRBs9El6_S7b_4EL6uOC3yDTsbCPJjGHGvrUiFGGnL4fkXVWPWkt8PI8gU12bHJ62jgMBNXNcZMCgEK4DUAZHUjDQ1tq39qGJIvB3wtkQi_wQ3QlCix7Ry_GX4ckiJcMju4ktqt82yg-- Received: from [68.142.241.238] by web53706.mail.re2.yahoo.com via HTTP; Wed, 09 Sep 2009 19:04:34 PDT X-Mailer: YahooMailWebService/0.7.338.2 X-Original-Date: Wed, 9 Sep 2009 19:04:34 -0700 (PDT) From: Kyrilian Dyer Subject: Re: [LML] Re: Legacy Flaps - Fowler vs Split X-Original-To: Lancair Mailing List X-Original-Cc: Lorn H Olsen MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Lorn,=0A=0AI wonder whether these two indicated airspeeds are correct. Hav= e you done static port position error testing near stall? With flaps exten= ded and retracted? I'm guessing most people don't. I wouldn't be surprise= d if flaps change the airflow near the static port(s)--either due to change= in aircraft attitude or more directly--enough to cause a few knots of airs= peed error.=0A=0AIf you want to check what effect the flaps have at low spe= ed without the toil of a full PEC evaluation you could do a rather quick ev= aluation. While flying at the same altitude and heading the same direction= in the same airmass, simply fly an airspeed a few knots above stall (say 8= 5 kias, in your case) with flaps up, and note your groundspeed (from GPS). = Then extend flaps and fly the same groundspeed and note your airspeed. Th= e indicated airspeeds shouldn't be compared to the groundspeed for accuracy= , but the difference in indicated airspeeds should be a good first order ap= proximation of the relative effect of your flaps on Pitot-static error. Th= is relative error could then be applied to your stall numbers to determine = the effect of flaps on your stall speed, for a given GW/CG.=0A=0A Cheers,= =0A- Kyrilian =0A=0A=0AOn Sep 8, 2009, at 9:23 PM, Lorn H Olsen wrote:=0A=0AOn my airplane, I stall at 80 kias with no flaps and 78= kias with 25=B0 of flap. 25=B0 of flap gives my lowest stall speed. I use = this setting for my instrument approaches.=0A=0A=0A=0A