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Brad, the stud on my door looks to be a bit loose. Is there an easy fix before it completely fails? Shane 89GG From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Brad Simmons
Sent: Tuesday, October 08, 2013 8:42 AM
To: lml@lancaironline.net
Subject: [LML] Re: Cabin door strut on IV series 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 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.
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