X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 17 Aug 2010 07:56:50 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-banded.atl.sa.earthlink.net ([209.86.89.70] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4433340 for lml@lancaironline.net; Mon, 16 Aug 2010 23:15:10 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.70; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=CwsiKL4R4OjLFwKcWNkILvR+Wo7kL+eZXnO10kx+Jzd2yj49Oyu3u9qQ4oByIgtx; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.51] (helo=[192.168.1.133]) by elasmtp-banded.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1OlCdH-0007Ia-DX for lml@lancaironline.net; Mon, 16 Aug 2010 23:14:35 -0400 From: Colyn Case Mime-Version: 1.0 (Apple Message framework v1078) Content-Type: multipart/alternative; boundary=Apple-Mail-67-912481299 Subject: Re: [LML] IV-P Door Window Replacement X-Original-Date: Mon, 16 Aug 2010 23:14:35 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <90D487E0-05A8-41EB-841E-B4226428EBDA@earthlink.net> X-Mailer: Apple Mail (2.1078) X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940abbc42f1722fd74af1827a9bb75f9492350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.51 --Apple-Mail-67-912481299 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Bob, thanks for the report. ouch! Is Jonathan going to make a modified gas strut with a snubber built in? On Aug 16, 2010, at 12:56 PM, Robert R Pastusek wrote: > I have completed replacement of the door window in my IV-P and N437RP = is at Brad Simmons=92 shop for painting. I promised to write a complete = report on this, and have made careful notes and pictures for this. It = appears the report will need to be delayed a bit, so I thought I should = provide a summary of what I believe to be the cause. Hopefully this will = help some of you in avoiding my mistakes. > =20 > The door window in N437RP, and IV-P, developed a crack parallel to the = back edge of the window at approximately 500 hours and two years in = service. The crack was completely covered by the inside and outside door = frame carbon fiber, and only visible as a 2 inch =93crackle=94 in the = otherwise dark edge of the Plexiglas when viewed at a sharp angle from = inside or outside of the door. I continued to fly the airplane for about = 10 hours, but did not pressurize it during this time. > =20 > I removed the transparency from the door by grinding away the outside = carbon cloth layers to reveal the outside edges of the Plexiglas. By = doing this carefully, I was able to determine that the crack was = approximately 4 inches long, parallel to, and about =BC=94 under the = back edge of the carbon window frame. Neither end of the crack extended = to the edge of the Plexiglas, and did not intersect either of the door = latch mounting holes that had been oversized, filled with Hysol and = re-drilled to size. > =20 > This discovery about the nature of the crack led me to conclude that = it was caused by flexing/twisting of the door frame in that immediate = area. While this could be caused by the latch located in the immediate = area, this seemed unlikely as the crack was almost an inch away and the = mounting through-holes showed no stress or cracking at all. > =20 > The other source of bending/twisting stress in that area is the = attachment point of the gas lift strut that holds the door open, and I = believe this to have been the source. On two recent occasions, the door = has been allowed to swing open hard in the wind against the air strut, = and one or both of these almost certainly caused the crack=97although I = did not see it at the time. I have routinely taxied the airplane over = rough ramps/etc with the canopy open, allowing it to bounce against the = restraining strut=85 a practice I won=92t do again. > =20 > I doubt this is the cause of all door window failures; in fact, mine = might have been unique, but I plan to take much better care of my door = in the future! Detailed report to the LML when I can. > =20 > Bob --Apple-Mail-67-912481299 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Bob,   thanks for the report. =  ouch!

Is Jonathan going to make a modified gas = strut with a snubber built in?

On Aug 16, 2010, at = 12:56 PM, Robert R Pastusek wrote:

I have completed replacement of the door window in = my IV-P and N437RP is at Brad Simmons=92 shop for painting. I promised = to write a complete report on this, and have made careful notes and = pictures for this. It appears the report will need to be delayed a bit, = so I thought I should provide a summary of what I believe to be the = cause. Hopefully this will help some of you in avoiding my = mistakes.
 
The door window in N437RP, and = IV-P, developed a crack parallel to the back edge of the window at = approximately 500 hours and two years in service. The crack was = completely covered by the inside and outside door frame carbon fiber, = and only visible as  a 2 inch =93crackle=94 in the otherwise dark = edge of the Plexiglas when viewed at a sharp angle from inside or = outside of the door. I continued to fly the airplane for about 10 hours, = but did not pressurize it during this time.
I removed the transparency from the door by grinding = away the outside carbon cloth layers to reveal the outside edges of the = Plexiglas. By doing this carefully, I was able to determine that the = crack was approximately 4 inches long, parallel to, and about =BC=94 = under the back edge of the carbon window frame. Neither end of the crack = extended to the edge of the Plexiglas, and did not intersect either of = the door latch mounting holes that had been oversized, filled with Hysol = and re-drilled to size.
 
This discovery about the nature = of the crack led me to conclude that it was caused by flexing/twisting = of the door frame in that immediate area. While this could be caused by = the latch located in the immediate area, this seemed unlikely as the = crack was almost an inch  away and the mounting through-holes = showed no stress or cracking at all.
The other source of bending/twisting stress in that = area is the attachment point of the gas lift strut that holds the door = open, and I believe this to have been the source. On two recent = occasions, the door has been allowed to swing open hard in the wind = against the air strut, and one or both of these almost certainly caused = the crack=97although I did not see it at the time. I have routinely = taxied the airplane over rough ramps/etc with the canopy open, allowing = it to bounce against the restraining strut=85 a practice I won=92t do = again.
 
I doubt this is the cause of all = door window failures; in fact, mine might have been unique, but I plan = to take much better care of my door in the future!  Detailed report = to the LML when I can.