X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 08 Oct 2013 10:56:21 -0400 Message-ID: X-Original-Return-Path: <2thman1@gmail.com> Received: from mail-oa0-f46.google.com ([209.85.219.46] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6506608 for lml@lancaironline.net; Tue, 08 Oct 2013 09:53:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.46; envelope-from=2thman1@gmail.com Received: by mail-oa0-f46.google.com with SMTP id k14so7439387oag.5 for ; Tue, 08 Oct 2013 06:52:51 -0700 (PDT) X-Received: by 10.182.227.136 with SMTP id sa8mr1294986obc.39.1381240371707; Tue, 08 Oct 2013 06:52:51 -0700 (PDT) X-Original-Return-Path: <2thman1@gmail.com> Received: from [10.7.8.10] (mobile-166-147-113-135.mycingular.net. [166.147.113.135]) by mx.google.com with ESMTPSA id b5sm3947541obj.8.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 08 Oct 2013 06:52:51 -0700 (PDT) References: In-Reply-To: Mime-Version: 1.0 (1.0) Content-Type: multipart/alternative; boundary=Apple-Mail-54BFD087-F1F5-477B-99C1-FDCCEE09CDFF X-Original-Message-Id: Content-Transfer-Encoding: 7bit X-Mailer: iPad Mail (10B329) From: John Barrett <2thman1@gmail.com> Subject: Re: [LML] Re: Cabin door strut on IV series X-Original-Date: Tue, 8 Oct 2013 09:52:47 -0400 X-Original-To: Lancair Mailing List --Apple-Mail-54BFD087-F1F5-477B-99C1-FDCCEE09CDFF Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Thanks Brad, Good advice. John Sent from my iPad On Oct 8, 2013, at 9:41 AM, "Brad Simmons" wrote: > John, > I could not view your YouTube video; it asked for a log in... > =20 > Door strut damage is becoming a common item as the fleet ages. We are seei= ng problems on probably a 3rd of the planes that we service. There have also= been at least a couple of cracked windows possibly attributed to the door s= trut stress placed on the door. > Assuming your ball and socket alignment isn't so bad that the range or mot= ion is exceeded, the other common issue is the stud wallowing out the hole t= hrough the carbon frame. Once it begins to move around, the threads will qui= ckly open up the hole diameter, and as the assembly becomes loose, the socke= t will either pop off, or damage the fingers in the socket. > There's more than one kind of ball and socket floating around out there, a= lso. Some don't have the same amount of motion as others, so if your replace= ment strut did not come from Lancair, make sure that the similar ends will a= ctually allow the needed rotation. > Adding a strap to the door to allow you to cushion the opening is a good i= dea also. I still see folks that land, unlatch the door and just push it up a= nd allow it to open on it's own (and you know who you are!!!). I can just ab= out guarantee you that the ball studs will be loose in their composite mount= s. > =20 > Brad Simmons > Airframes Inc. > 39 Airport Rd. > Milan, TN 38358 > 731-686-3610 > 731-686-3613 fax > www.airframesinc.com > ----- Original Message ----- > From: John Barrett > To: lml@lancaironline.net > Sent: Tuesday, October 08, 2013 6:55 AM > Subject: [LML] Cabin door strut on IV series >=20 > Hi all, >=20 > I have to say that my first attendance to a LOBO fly in was awesome ( to u= se my children's and their children's cliche). The chance to meet so many e= nthusiastic, knowledgeable and fun Lancair folks provided WAY more benefit t= han I ever would have imagined. Thank you to the board, the vendors, presen= ters and to everyone involved. I loved it and so did my wife, Anne.=20 >=20 > I saw some folks examining a IVP door strut on Saturday I think. The atta= chment at the frame was very loose so that the ball stud was flopping around= . Close inspection showed that the door frame was cracked under the stud. I= 'm not sure whose plane this was but I think it is the one that vibration me= asurement equipment had recently been attached to for studies. >=20 > The door strut triggered memories of similar occurrence with my strut a c= ouple of years ago prior to first flight. I would guess the smart folks who= noticed this also figured out the reason for the failure, but just in case I= will share what I found and how I dealt with it. >=20 > The problem with the door strut is that the arc described by the strut dur= ing opening and closing exceeds the range of motion built into the ball stud= socket on the lower end of the strut. Therefore the door frame is wrenched= back and forth during door operation when the stud is attached to the door f= rame without modification to the frame. There is a plane you can find by = experimentation or by mathematical exercise if you are so gifted and inclin= ed to pursue (I am not) that will allow the socket to move within the design= limits and therefore not stress the stud and the door frame. Once this pla= ne is determined, you can use a small washer of wood, foam or other material= to shape the door frame where the stud penetrates the frame. You'll need t= o cut out a bit of the frame to accomplish this. since my frame was broken h= ere it made that part simple. Super glue or hot glue can hold the form in p= lace. Then lay up two BID of carbon fibre cloth over the form and remove th= e form material when done. Lay up several layers on the back side to streng= then the mod and to secure it by sandwiching on both sides of remaining fram= e.=20 >=20 > It gets a little more complicated because the back side in my case was in v= ery tight quarters. When complete I found that the screw stud on the ball st= ud part was too short. I was able to go online and find a replacement at ve= ry nominal cost and that had plenty of thread length for the purpose. >=20 > I have uploaded a video to YouTube of the way the attachment looks now. S= ee link below. I hope it helps someone. >=20 > http://youtu.be/d3sBMgVncMM >=20 > John Barrett > N31VP >=20 > Sent from my iPad >=20 --Apple-Mail-54BFD087-F1F5-477B-99C1-FDCCEE09CDFF Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit
Thanks Brad,

Good advice.

John

Sent from my iPad


On Oct 8, 2013, at 9:41 AM, "Brad Simmons" <brad@airframesinc.com> wrote:

John,
I could not view your YouTube video; it asked for a log in...
 
Door strut damage is becoming a common item as the fleet ages. We are seeing problems on probably a 3rd of the planes that we service. There have also been at least a couple of cracked windows possibly attributed to the door strut stress placed on the door.
Assuming your ball and socket alignment isn't so bad that the range or motion is exceeded, the other common issue is the stud wallowing out the hole through the carbon frame. Once it begins to move around, the threads will quickly open up the hole diameter, and as the assembly becomes loose, the socket will either pop off, or damage the fingers in the socket.
There's more than one kind of ball and socket floating around out there, also. Some don't have the same amount of motion as others, so if your replacement strut did not come from Lancair, make sure that the similar ends will actually allow the needed rotation.
Adding a strap to the door to allow you to cushion the opening is a good idea also. I still see folks that land, unlatch the door and just push it up and allow it to open on it's own (and you know who you are!!!). I can just about guarantee you that the ball studs will be loose in their composite mounts.
 
Brad Simmons
Airframes Inc.
39 Airport Rd.
Milan, TN  38358
731-686-3610
731-686-3613 fax
www.airframesinc.com
----- Original Message -----
Sent: Tuesday, October 08, 2013 6:55 AM
Subject: [LML] Cabin door strut on IV series

Hi all,

I have to say that my first attendance to a LOBO fly in was awesome ( to use my children's and their children's cliche).  The chance to meet so many enthusiastic, knowledgeable and fun Lancair folks provided WAY more benefit than I ever would have imagined.  Thank you to the board, the vendors, presenters and to everyone involved.  I loved it and so did my wife, Anne.  

I saw some folks examining a IVP door strut on Saturday I think.  The attachment at the frame was very loose so that the ball stud was flopping around.  Close inspection showed that the door frame was cracked under the stud.  I'm not sure whose plane this was but I think it is the one that vibration measurement equipment had recently been attached to for studies.

The door strut triggered memories of  similar occurrence with my strut a couple of years ago prior to first flight.  I would guess the smart folks who noticed this also figured out the reason for the failure, but just in case I will share what I found and how I dealt with it.

The problem with the door strut is that the arc described by the strut during opening and closing exceeds the range of motion built into the ball stud socket on the lower end of the strut.  Therefore the door frame is wrenched back and forth during door operation when the stud is attached to the door frame without modification to the frame.  There is a plane you can find by experimentation or by mathematical exercise if you are so gifted and inclined to pursue (I am not) that will allow the socket to move within the design limits and therefore not stress the stud and the door frame.  Once this plane is determined, you can use a small washer of wood, foam or other material to shape the door frame where the stud penetrates the frame.  You'll need to cut out a bit of the frame to accomplish this.  since my frame was broken here it made that part simple.  Super glue or hot glue can hold the form in place.  Then lay up two BID of carbon fibre cloth over the form and remove the form material when done.  Lay up several layers on the back side to strengthen the mod and to secure it by sandwiching on both sides of remaining frame. 

It gets a little more complicated because the back side in my case was in very tight quarters. When complete I found that the screw stud on the ball stud part was too short.  I was able to go online and find a replacement at very nominal cost and that had plenty of thread length for the purpose.

I have uploaded a video to YouTube of the way the attachment looks now.  See link below.  I hope it helps someone.


John Barrett
N31VP

Sent from my iPad

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