Today's Message Index:
----------------------
1. 05:44 PM - Moose: Elevator Tip Skin cracks (Ted Waltman)
2. 08:01 PM - Re: Moose: Elevator Tip Skin cracks (Scott Aldrich)
3. 08:10 PM - Re: Moose: Elevator Tip Skin cracks (Scott Aldrich)
Message 1
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| Subject: | Moose: Elevator Tip Skin cracks |
Guess I'm just lucky to find these things. Hopefully by documenting the
issues I find such will help others still in the build process or prompt
others that are now flying to double check their planes.
Last year I discovered small cracks in the underside of both elevator tip
skins (part # EL-313). I drilled relief holes and kept an eye on them. On
the left side, I had to drill a second set of holes later in the year.
Looking at the extent of the cracks, particularly on the left (pilot) side
it is evident that a major "redo" of this area is now in order. As such,
I've asked a few friends what techniques they might suggest....
[ Please see the rest of my comments and pictures here:
http://www.i1ci.com/Flying/Moose/Elevator/Elevator.html ]
Thank you for your input.
Ted Waltman
Moose N142SR
Message 2
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| Subject: | Moose: Elevator Tip Skin cracks |
Ted,
Thanks for sharing. This is the only way we will get all the kinks worked
out of our airplanes. It looks to me like the moment arm of the elevator
counter weights is too much for the structure and the bottom skin is just
trying to buckle under compression. You're only getting cracks on the
bottom most likely from the loads imposed on landings (No, I am not saying
you are making hard landings <grin>) just thinking it is not a vibration
problem like the other cracks.
I checked out the pictures and comments on your website. The sea fin mod
and beef up was only on the Stabilizer end rib and rear spar under the
outboard elevator hinge, it had nothing to do with the elevator itself -
what you have is new, or at least no one else has brought it up yet.
I would take the path of least resistance and use your second idea for a
fix. Just add a full length doubler that spans the elevator end rib and the
tip counterbalance rib. I would also add external doubler plates on the top
and bottom that span that area, I doubt they would need to go all the way.
You mention about being able to pick up the elevator tip weight - not a
problem you can drill right into the soft lead and put rivet right into it.
That is the way your aileron balance weights are held in.
The amazing thing, looking at your pictures, is that you do not have the
cracks on the stabilizer end ribs and you do not have the reinforcement per
the bulletin in there.
Scott
Moose 174
_____
From: owner-murphymoose-list-server@matronics.com
[mailto:owner-murphymoose-list-server@matronics.com] On Behalf Of Ted
Waltman
Sent: Sunday, May 07, 2006 6:44 PM
Subject: MurphyMoose-List: Moose: Elevator Tip Skin cracks
Guess I'm just lucky to find these things. Hopefully by documenting the
issues I find such will help others still in the build process or prompt
others that are now flying to double check their planes.
Last year I discovered small cracks in the underside of both elevator tip
skins (part # EL-313). I drilled relief holes and kept an eye on them. On
the left side, I had to drill a second set of holes later in the year.
Looking at the extent of the cracks, particularly on the left (pilot) side
it is evident that a major "redo" of this area is now in order. As such,
I've asked a few friends what techniques they might suggest....
[ Please see the rest of my comments and pictures here:
http://www.i1ci.com/Flying/Moose/Elevator/Elevator.html ]
Thank you for your input.
Ted Waltman
Moose N142SR
Message 3
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| Subject: | Moose: Elevator Tip Skin cracks |
Just to add, if you are going to be drilling out the top and bottom skins
there anyway it wouldn't be too hard to add and internal doublers on both
sides that pick up the spar too.
Scott
_____
From: owner-murphymoose-list-server@matronics.com
[mailto:owner-murphymoose-list-server@matronics.com] On Behalf Of Scott
Aldrich
Sent: Sunday, May 07, 2006 9:01 PM
Subject: RE: MurphyMoose-List: Moose: Elevator Tip Skin cracks
Ted,
Thanks for sharing. This is the only way we will get all the kinks worked
out of our airplanes. It looks to me like the moment arm of the elevator
counter weights is too much for the structure and the bottom skin is just
trying to buckle under compression. You're only getting cracks on the
bottom most likely from the loads imposed on landings (No, I am not saying
you are making hard landings <grin>) just thinking it is not a vibration
problem like the other cracks.
I checked out the pictures and comments on your website. The sea fin mod
and beef up was only on the Stabilizer end rib and rear spar under the
outboard elevator hinge, it had nothing to do with the elevator itself -
what you have is new, or at least no one else has brought it up yet.
I would take the path of least resistance and use your second idea for a
fix. Just add a full length doubler that spans the elevator end rib and the
tip counterbalance rib. I would also add external doubler plates on the top
and bottom that span that area, I doubt they would need to go all the way.
You mention about being able to pick up the elevator tip weight - not a
problem you can drill right into the soft lead and put rivet right into it.
That is the way your aileron balance weights are held in.
The amazing thing, looking at your pictures, is that you do not have the
cracks on the stabilizer end ribs and you do not have the reinforcement per
the bulletin in there.
Scott
Moose 174
_____
From: owner-murphymoose-list-server@matronics.com
[mailto:owner-murphymoose-list-server@matronics.com] On Behalf Of Ted
Waltman
Sent: Sunday, May 07, 2006 6:44 PM
Subject: MurphyMoose-List: Moose: Elevator Tip Skin cracks
Guess I'm just lucky to find these things. Hopefully by documenting the
issues I find such will help others still in the build process or prompt
others that are now flying to double check their planes.
Last year I discovered small cracks in the underside of both elevator tip
skins (part # EL-313). I drilled relief holes and kept an eye on them. On
the left side, I had to drill a second set of holes later in the year.
Looking at the extent of the cracks, particularly on the left (pilot) side
it is evident that a major "redo" of this area is now in order. As such,
I've asked a few friends what techniques they might suggest....
[ Please see the rest of my comments and pictures here:
http://www.i1ci.com/Flying/Moose/Elevator/Elevator.html ]
Thank you for your input.
Ted Waltman
Moose N142SR
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