Re: LS1 midspan hinge repair

One Sky Dog


These center hinges have failed before. Steel is a lot better in fatigue than Al  but if the inflight stress levels are close to the limit it is an insidious problem. It is obviously not a shear failure of they would be breaking upon loading.

Reducing stress is the only answer. This is a materials problem. Either increase cross section, increase load transfer points, or redesign like Jay has done.

Fatigue = repeated cyclic loading below the yield point internal material flaws move to high stress areas over time resulting in cracks and final failure at loads below the design point.

My $0.02 worth of armchair analysis.


On Monday, May 9, 2022, 4:47 AM, Frankenbird Vern <smeshno1@...> wrote:

 Mike.. if Bob or Jim can photo the fail and present it? ..might give some idea of what the cause was.

  Could be from not breaking the sharp edges or possibly the material itself.  .125" is fairly robust so it makes
 me wonder why. 


From: <> on behalf of Terry Crouch via <Q1terryMDT@...>
Sent: Sunday, May 8, 2022 2:46 PM
To: <>
Subject: Re: [Q-List] LS1 midspan hinge repair
There are 6 appendix sheets for the LS1, CS-17 is on the first one.  Send me your phone # Mike and I will send a photo.

Terry Crouch
Quickie N14TC

-----Original Message-----
From: Mike via <n7000t@...>
Sent: Sun, May 8, 2022 12:15 pm
Subject: [Q-List] LS1 midspan hinge repair

Hi all,
I flew my Q200 to Livermore recently to have bob Farnahm ( original builder) help me do my condition inspection. Upon removal of the right elevator we found the midspan hinge was broken. Bob and Jim Patillo have offered to fix in my absence and since I live in Nevada. Problem is none of us can find the LS1 addendum for the Q200. Especially needing the CS17 part to help with the fix. I’ve been on quick heads and Jon finley’ site to no avail. Does anyone have a PDF file you can send me on that topic (maybe Sam that has rebuilt his canard?
Thanks in advance 

Mike Q200.   N200QK.    
pM me please 

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