Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Fri, 10 Sep 2004 09:46:35 -0400 Message-ID: X-Original-Return-Path: Received: from sharedlx1.hugehosting.com ([65.38.161.57] verified) by logan.com (CommuniGate Pro SMTP 4.2.1) with ESMTP-TLS id 404985 for lml@lancaironline.net; Fri, 10 Sep 2004 01:09:19 -0400 Received-SPF: none receiver=logan.com; client-ip=65.38.161.57; envelope-from=thorn@starflight.aero Received: from valinhawk (user-0cetji7.cable.mindspring.com [24.238.206.71]) (authenticated (0 bits)) by sharedlx1.hugehosting.com (8.11.6/8.11.6) with ESMTP id i8A40DQ19564 for ; Fri, 10 Sep 2004 00:00:13 -0400 From: "Valin & Allyson Thorn" X-Original-To: "'Lancair Mailing List'" Subject: Canopy Charging Concerns X-Original-Date: Thu, 9 Sep 2004 23:31:43 -0500 X-Original-Message-ID: <000001c496ef$16dd5290$6401a8c0@valinhawk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.2616 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 I've been meaning to ask if anyone has seen any problems with Legacy canopy charging/discharging for some time now and then I saw Rob's post: ------------------------------------------ Regarding: Rob Logan Subject: [LML] Re: P-static blew my VM1000, autopilot and trim indicator today Flying back from Florida once, day IMC, noticed a fuzzy feeling in my arms, and all the hairs were standing straight out.. then crack, it felt like a sharp hammer had been raped on my head.. then another sharp pain.. dang, these things hurt! the huge plexi glass canopy was generating lots of charge and it was discharging through my head! as I shrunk down to get away from the canopy the arcs just got longer and hurt more!. tried grounding my self with my elbow but was soon VMC and things returned to normal... no instrument loss, total time maybe 2mins? Rob -------------------------------------------------- A couple of years ago someone on the LML recounted the early history of plexiglass/acrylic canopies in the Air Force. As I remember, they had several mysterious crashes of one of their new jet fighters. They ended up determining that the new acrylic canopies were picking up a big electrical charge when in IMC and were discharging to the pilot's helmet/head -- electrocuting them. I'm guessing that is why almost all fighters now have a zig zag shaped metallic piece bonded to their canopies -- to provide a discharge path back to the fuselage. I have to say, I couldn't help but wonder about Wendel Durr's accident where he'd entered severe storms and the preliminary reports said his flight ended in a "descending gradual right turn", as I remember... Has anyone heard any more details on the cause -- beyond entering Level 5 thunderstorms? Does anyone out there have enough background on the subject to tell us how to provide a good discharge path for the electrons on the canopy back to the fuselage? Also, I think this is an example of the kind of things that when someone in the community experiences they should be reported to everyone right away. It may be nothing or it may be the first indications of something very serious that we need to deal with. It's one thing to zap your instruments -- it's a whole 'nother thing to really zap the instrument between your ears... Valin Thorn Legacy, Houston