X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [66.94.81.250] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 5.0c1) with HTTP id 684449 for lml@lancaironline.net; Sat, 27 Aug 2005 21:24:29 -0400 From: "Marvin Kaye" Subject: Re: [LML] Thunderstorm Survival To: lml X-Mailer: CommuniGate Pro WebUser v5.0c1 Date: Sat, 27 Aug 2005 21:24:29 -0400 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format="flowed" Content-Transfer-Encoding: 8bit Posted for Walter Atkinson : Lowering flaps results in a weaker wing due to the movement of the center of lift aft. Don't lower flaps. walter On Aug 26, 2005, at 11:35 AM, Robert Overmars wrote: Saluti tutti,   Perhaps those pilots contemplating extending flaps in the case of inadvertent penetration of thunderstorms should read FAR 23.345  (a) (1) (2)appended below.   Martin Hollman writes in M.A.D. vol I, "...A limit load factor of 0.5 x n1 is used at Vf. This condition gives us the maximum twisting load on the wing.... Twisting causes high in-plane shear stress and together with twisting generates high rear spar loads"  (n1 is the positive manoeuvre limit load factor)   Never having penetrated one of those nasty thunderies I still can't help but think that compromising the aircraft G load limit, the gust design strength, and restricting the aircraft speed envelope  to Vf at a time when the maximum strength/gust response/speed may well be needed is just not a good idea. Test piloting the ultimate flap system or wing strength at such a time could really spoil your day.