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Webpage on Cracked bulkheads

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Ted Waltman

Webpage on Cracked bulkheads

Post by Ted Waltman » Sat Feb 18, 2012 10:59 am

Folks on the builders list, as well as Robin Dyck & Brent DeFazio at
Murphy Aircraft:

I built a webpage today to document severe cracking I found in the
FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
inadequate design of the tailwheel stinger attach points in the Murphy
Moose aircraft.

http://www.i1ci.com/flying/moose/tail/tail.html

This is clearly a safety issue, as noted on my webpage. Murphy aircraft
knows about this issue. I personally believe that Murphy Aircraft
should issue a service bulletin on this serious problem with the current
design. In the meantime, as documented on my webpage, I am working with
several members of the builders list with a prototype of a possible fix.

I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
Fuselage. This is one of the same pictures on my webpage.

Ted Waltman
Moose N142SR
Lakewood, CO
ted@i1ci.com
cell: 303-378-4987




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Bob Patterson

Webpage on Cracked bulkheads

Post by Bob Patterson » Sat Feb 18, 2012 10:59 am

Hi Ted !

Well done web page ! Very clear, and highlights the problem.

Interesting that the tear follows the rivet holes - suggests
to me that the vertical rivets were installed before the horizontal
ones at the bottom, and the bulkhead was slightly mis-aligned,
pre-stressing the bulkhead material....

Given that this is a safety issue, as you describe well on the
web page, and that it is being found in several instances, I agree
that Murphy should issue a safety bulletin strongly suggesting
regular inspection, and repair, of this area, for those builders
who don't have the advantage of the wisdom shared on this list !
Also for Elite builders, who, although they don't have the high
loads of the Moose, do share this stinger attach method.

Your proposed fix looks substantial, and looks like it would
help absorb some of the shocks - I'm wondering why there is just
a cradle for the stinger, though, instead of a hole, so it would
be supported all around ??? This way, you are counting on the
bolts for all of the load in one direction - can't be sure from the
photo, but looks like downward loads ?? (IANAE !! ;-) )
(I am not an engineer ! ;-) :-) )

Please keep us all posted on your progress and results !
And thanks for the web site - I'm sure it will help others !

......bobp

-------------------------------orig.-------------------------
On Monday 05 September 2005 07:40 pm, Ted Waltman wrote:
Folks on the builders list, as well as Robin Dyck & Brent DeFazio at
Murphy Aircraft:

I built a webpage today to document severe cracking I found in the
FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
inadequate design of the tailwheel stinger attach points in the Murphy
Moose aircraft.

http://www.i1ci.com/flying/moose/tail/tail.html

This is clearly a safety issue, as noted on my webpage. Murphy aircraft
knows about this issue. I personally believe that Murphy Aircraft
should issue a service bulletin on this serious problem with the current
design. In the meantime, as documented on my webpage, I am working with
several members of the builders list with a prototype of a possible fix.

I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
Fuselage. This is one of the same pictures on my webpage.

Ted Waltman
Moose N142SR
Lakewood, CO
ted@i1ci.com
cell: 303-378-4987




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pequeajim

Webpage on Cracked bulkheads

Post by pequeajim » Sat Feb 18, 2012 10:59 am

Not to over simplify things, but coming from a giant scale RC perspective,
why don't they use some type of leaf spring configuration to absorb the shock
at the tail wheel?

Does this create too much bounce?


-> >
-> > I built a webpage today to document severe cracking I found in the
-> > FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
-> > inadequate design of the tailwheel stinger attach points in the Murphy
-> > Moose aircraft.
-> >
-> > http://www.i1ci.com/flying/moose/tail/tail.html
-> >
-> > This is clearly a safety issue, as noted on my webpage. Murphy aircraft
-> > knows about this issue. I personally believe that Murphy Aircraft
-> > should issue a service bulletin on this serious problem with the current
-> > design. In the meantime, as documented on my webpage, I am working with
-> > several members of the builders list with a prototype of a possible fix.
-> >
-> > I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
-> > Fuselage. This is one of the same pictures on my webpage.
-> >
-> > Ted Waltman
-> > Moose N142SR
-> > Lakewood, CO
-> > ted@i1ci.com
-> > cell: 303-378-4987
-> >
-> >
-> >
-> >
-> > -----------------------------------------------------------------
-> > List archives located at: https://www.dcsol.com/login
-> > username "rebel" password "builder"
-> > Subscription services located at:
-> > https://www.dcsol.com/public/code/html-subscribe.htm
-> > List administrator: mike.davis@dcsol.com
-> > -----------------------------------------------------------------
-> >
-> >
-> >





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Bob Patterson

Webpage on Cracked bulkheads

Post by Bob Patterson » Sat Feb 18, 2012 10:59 am

Good question, Jim ! In many cases, just like spring gear,
split flaps, and electric flaps - the answer is "Cessna did it,
so it must be good" ! ;-) :-)

Seriously, I think Murphy was trying to improve on past
designs, find a better way to handle the larger loads, and simplify
construction - everyone tries to improve things to the best of their
abilities, and following what others have done. You don't see big
leaf springs on DC-3's .... I'm no engineer, but there must be
a reason ! Sometimes, details don't work out as well as hoped .....
... ask anyone who has owned a Cessna 180/185 for a few years about
the spring gear box rebuilds ! ( ... see PPONK web site ! ;-) )

Still, this is the beauty of homebuilding EXPERIMENTAL aircraft -
you get to try different methods, and we're lucky enough to
have this web site to share what works ! Thanks Mike !!!! :-)

......bobp

-------------------------------orig.-------------------------
On Monday 05 September 2005 11:04 pm, pequeajim@dcsol.com wrote:
Not to over simplify things, but coming from a giant scale RC perspective,
why don't they use some type of leaf spring configuration to absorb the
shock
at the tail wheel?

Does this create too much bounce?


-> >
-> > I built a webpage today to document severe cracking I found in the
-> > FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
-> > inadequate design of the tailwheel stinger attach points in the Murphy
-> > Moose aircraft.
-> >
-> > http://www.i1ci.com/flying/moose/tail/tail.html
-> >
-> > This is clearly a safety issue, as noted on my webpage. Murphy
aircraft
-> > knows about this issue. I personally believe that Murphy Aircraft
-> > should issue a service bulletin on this serious problem with the
current
-> > design. In the meantime, as documented on my webpage, I am working
with
-> > several members of the builders list with a prototype of a possible
fix.
-> >
-> > I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
-> > Fuselage. This is one of the same pictures on my webpage.
-> >
-> > Ted Waltman
-> > Moose N142SR
-> > Lakewood, CO
-> > ted@i1ci.com
-> > cell: 303-378-4987
-> >
-> >
-> >
-> >
-> > -----------------------------------------------------------------
-> > List archives located at: https://www.dcsol.com/login
-> > username "rebel" password "builder"
-> > Subscription services located at:
-> > https://www.dcsol.com/public/code/html-subscribe.htm
-> > List administrator: mike.davis@dcsol.com
-> > -----------------------------------------------------------------
-> >
-> >
-> >





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Ted Waltman

Webpage on Cracked bulkheads

Post by Ted Waltman » Sat Feb 18, 2012 10:59 am

Thanks for your comments Bob.

You're right about the new, prototype bracket only supporting downward
loads via the cradle [and upward loads via two bolts]. Don't forget
that the rear pivot bracket translates a landing load into a downward
load at the forward bracket. As I said, it is a prototype which only
time and a lot of landings will show where it's issues are [everything
will have some issue].

Ted

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Bob Patterson
Sent: Monday, September 05, 2005 8:37 PM
To: rebel-builders@dcsol.com
Cc: Rdyck@murphyair.com; bdefazio@murphyair.com
Subject: Re: Webpage on Cracked bulkheads



Hi Ted !

Well done web page ! Very clear, and highlights the problem.

Interesting that the tear follows the rivet holes - suggests to me
that the vertical rivets were installed before the horizontal ones at
the bottom, and the bulkhead was slightly mis-aligned,
pre-stressing the bulkhead material....

Given that this is a safety issue, as you describe well on the web
page, and that it is being found in several instances, I agree
that Murphy should issue a safety bulletin strongly suggesting
regular inspection, and repair, of this area, for those builders
who don't have the advantage of the wisdom shared on this list ! Also
for Elite builders, who, although they don't have the high loads of the
Moose, do share this stinger attach method.

Your proposed fix looks substantial, and looks like it would help
absorb some of the shocks - I'm wondering why there is just a cradle for
the stinger, though, instead of a hole, so it would be supported all
around ??? This way, you are counting on the bolts for all of the load
in one direction - can't be sure from the
photo, but looks like downward loads ?? (IANAE !! ;-) )
(I am not an engineer ! ;-) :-) )

Please keep us all posted on your progress and results ! And thanks
for the web site - I'm sure it will help others !

......bobp

-------------------------------orig.-------------------------
On Monday 05 September 2005 07:40 pm, Ted Waltman wrote:
Folks on the builders list, as well as Robin Dyck & Brent DeFazio at
Murphy Aircraft:

I built a webpage today to document severe cracking I found in the
FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
inadequate design of the tailwheel stinger attach points in the Murphy
Moose aircraft.

http://www.i1ci.com/flying/moose/tail/tail.html

This is clearly a safety issue, as noted on my webpage. Murphy
aircraft knows about this issue. I personally believe that Murphy
Aircraft should issue a service bulletin on this serious problem with
the current design. In the meantime, as documented on my webpage, I
am working with several members of the builders list with a prototype
of a possible fix.

I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
Fuselage. This is one of the same pictures on my webpage.

Ted Waltman
Moose N142SR
Lakewood, CO
ted@i1ci.com
cell: 303-378-4987




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Ted Waltman

Webpage on Cracked bulkheads

Post by Ted Waltman » Sat Feb 18, 2012 10:59 am

One reason not to go to a leaf spring mechanism is the major rework that
such would require. The prototype on the webpage only requires a new
doubler and the new parts bolt directly to the existing bulkheads.

We did scratch our heads on the leaf spring idea, but couldn't come up
with a solution that wouldn't require rework plus, any solution would
likely involve adding some additional rubber(?) damping mechanism
anyway.

We'll try this approach; if someone has a design idea for a leaf spring
that would improve the situation please forward to me.

Ted Waltman

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
pequeajim@dcsol.com
Sent: Monday, September 05, 2005 9:05 PM
To: rebel-builders@dcsol.com
Subject: Re: Webpage on Cracked bulkheads


Not to over simplify things, but coming from a giant scale RC
perspective,
why don't they use some type of leaf spring configuration to absorb the
shock
at the tail wheel?

Does this create too much bounce?


-> >
-> > I built a webpage today to document severe cracking I found in the
-> > FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
-> > inadequate design of the tailwheel stinger attach points in the
-> > Murphy Moose aircraft.
-> >
-> > http://www.i1ci.com/flying/moose/tail/tail.html
-> >
-> > This is clearly a safety issue, as noted on my webpage. Murphy
-> > aircraft knows about this issue. I personally believe that Murphy
-> > Aircraft should issue a service bulletin on this serious problem
-> > with the current design. In the meantime, as documented on my
-> > webpage, I am working with several members of the builders list
-> > with a prototype of a possible fix.
-> >
-> > I also posted a picture of the cracks in my FUS-358 in area 107 -
-> > S/M Fuselage. This is one of the same pictures on my webpage.
-> >
-> > Ted Waltman
-> > Moose N142SR
-> > Lakewood, CO
-> > ted@i1ci.com
-> > cell: 303-378-4987
-> >
-> >
-> >
-> >
-> > -----------------------------------------------------------------
-> > List archives located at: https://www.dcsol.com/login username
-> > "rebel" password "builder" Subscription services located at:
-> > https://www.dcsol.com/public/code/html-subscribe.htm
-> > List administrator: mike.davis@dcsol.com
-> > -----------------------------------------------------------------
-> >
-> >
-> >





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Dale Fultz

Webpage on Cracked bulkheads

Post by Dale Fultz » Sat Feb 18, 2012 10:59 am

As Ted has stated this is a prototype I am sure improvements can be made.
When it was designed, my thinking was that if MAM mounts the original rigid
no rubber anywhere and this has rubber front and rear and two mounting bolts
should surely be better then the original one bolt. If not Bob, you better
call MAM and tell them that there one bolt is really a safety issue. If I am
thinking wrong here please by all means let me know. We were trying to make
it safe without a lot of extra weight and make it an affordable for anyone
that wants it if it works out. Dale SR-033




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Bob Patterson

Webpage on Cracked bulkheads

Post by Bob Patterson » Sat Feb 18, 2012 10:59 am

Looks good Ted ! I was just confused, as the picture, I guess,
is upside down, or I'm viewing it wrong ... wasn't sure if the opening
on the cradle was up or down. From your description, it is open at the
top, and the upward loads carried by the bolts are just the weight of
the wheel & stinger .... should be no problem !

My comments weren't meant as a criticism, Dale - I admire the
work you guys are doing ! Really like the idea of some rubber in
there for shock absorbing -just wondered why a cradle instead of a
hole, with support all around - but I guess the cradle would make
installation & removal of the stinger easier.... We're all learning -
that's the great thing about homebuilts !

Please keep the group posted on progress - we all need the shared
experience & guidance !! Thanks for leading the charge ! :-)

......bobp


-------------------------------orig.-------------------------
On Tuesday 06 September 2005 08:23 am, Ted Waltman wrote:
Thanks for your comments Bob.

You're right about the new, prototype bracket only supporting downward
loads via the cradle [and upward loads via two bolts]. Don't forget
that the rear pivot bracket translates a landing load into a downward
load at the forward bracket. As I said, it is a prototype which only
time and a lot of landings will show where it's issues are [everything
will have some issue].

Ted

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Bob Patterson
Sent: Monday, September 05, 2005 8:37 PM
To: rebel-builders@dcsol.com
Cc: Rdyck@murphyair.com; bdefazio@murphyair.com
Subject: Re: Webpage on Cracked bulkheads



Hi Ted !

Well done web page ! Very clear, and highlights the problem.

Interesting that the tear follows the rivet holes - suggests to me
that the vertical rivets were installed before the horizontal ones at
the bottom, and the bulkhead was slightly mis-aligned,
pre-stressing the bulkhead material....

Given that this is a safety issue, as you describe well on the web
page, and that it is being found in several instances, I agree
that Murphy should issue a safety bulletin strongly suggesting
regular inspection, and repair, of this area, for those builders
who don't have the advantage of the wisdom shared on this list ! Also
for Elite builders, who, although they don't have the high loads of the
Moose, do share this stinger attach method.

Your proposed fix looks substantial, and looks like it would help
absorb some of the shocks - I'm wondering why there is just a cradle for
the stinger, though, instead of a hole, so it would be supported all
around ??? This way, you are counting on the bolts for all of the load
in one direction - can't be sure from the
photo, but looks like downward loads ?? (IANAE !! ;-) )
(I am not an engineer ! ;-) :-) )

Please keep us all posted on your progress and results ! And thanks
for the web site - I'm sure it will help others !

......bobp

-------------------------------orig.-------------------------
On Monday 05 September 2005 07:40 pm, Ted Waltman wrote:
Folks on the builders list, as well as Robin Dyck & Brent DeFazio at
Murphy Aircraft:

I built a webpage today to document severe cracking I found in the
FUS-358 bulkhead and the FUS-438 (Rear spar bulkhead), due to the
inadequate design of the tailwheel stinger attach points in the Murphy
Moose aircraft.

http://www.i1ci.com/flying/moose/tail/tail.html

This is clearly a safety issue, as noted on my webpage. Murphy
aircraft knows about this issue. I personally believe that Murphy
Aircraft should issue a service bulletin on this serious problem with
the current design. In the meantime, as documented on my webpage, I
am working with several members of the builders list with a prototype
of a possible fix.

I also posted a picture of the cracks in my FUS-358 in area 107 - S/M
Fuselage. This is one of the same pictures on my webpage.

Ted Waltman
Moose N142SR
Lakewood, CO
ted@i1ci.com
cell: 303-378-4987




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