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From: "Alister Yeoman" <
yeoman@voyager.co.nz>
To: "Murphy Rebel" <
murphy-rebel@dcsol.com>
Subject: Re: Spring Gear fix ???
Date: Tue, 19 Jan 1999 15:53:36 +1300
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Hi Jim,
I am very disappointed that Murphy have not addressed this, they told me
they would.
The issue I believe is that the spacer system that holds the outer straddle
bolts on the spring gear is not up to it.
It is poorly designed, firstly, the spacer is the wrong diameter for the
bolt, secondly, because the outer gear bolts are so close to the edge of
the carrythrough the spacer has to be shaped to fit the top corner of the
carrythrough, thirdly, the bottom of the spacer is sitting against the
bottom plates not on the carrythough.
The sequence of events appears to be, as the spring gear is settling in,
the spacer, because it is the wrong diameter ( to big), can move a little
sideways. Then because the spacer is shaped, a little slack develops ( it
only needs to be a few thou ).
Once there is a little room to move things start happening quite quickly,
the front bolt is the one that causes the problem because of the braking
loads, the top of the carrythrough crushes downwards and then starts to
punch the spacer into the bottom plates pushing them away from the
carrythrough and pulling the rivets out.
This is not just a story, it happened to me and I know for a fact there are
others out there with damage in this area.
The perfect fix of course is to mill solid aluminum block inserts for the
carrythrough to capture the outer gear bolts and the three AN3 bolts in
that area, this actually is what I have done and it works really well. The
down side to that is that the side panels have to come of to do this, so it
is not really a good retro fix option. Murphy, they say, have been working
on another fix option, I thought they would have had it sorted by now.
The other thing to do is to retighten the gear bolts very frequently in the
early stages of the taxiing and flying program. The rear outer gear bolt
inspection panel as per the Manual should not be riveted on but should be
made to be easily removed so that tightening the rear bolt is no big drama.
Also I think the lower strut and gear fairings should be left off until say
10hrs have been flown.
I have done these mods, also put .032 panels on the lower rolled corner and
under the doors sills, beefed up the FUS 35 and put two rows of rivets on
each flange on it.
I also moved to 3/8 outer bolts and to 7/16 inner gear bolts, this was my
choice,I am not saying it is necessary
I have also interpiched the doorpost rivets ( doubled up ) and because of
the type of work I am doing with the plane I have fitted 850-6 tyres.
Since the repairs I have done about 25 hrs into some very rough places and
things are holding up really well, I am anticipating no more problems. What
a neat aircraft!!!
I hope this helps.
Cheers
Alister
----------
From:
JimsRebel@aol.com
To:
murphy-rebel@dcsol.com
Subject: Spring Gear fix ???
Date: Tuesday, January 19, 1999 12:55 PM
Hi Alister
Regarding the spring gear ... Murphy has been quiet about any changes in
the
area of the sping gear. I talked to Grant about this and it didn't seem
to me
that they were planning a mod or retrofit kit to stengthen the spring
gear. I
would like to know what you did to the gear to strengthen it.
Thanks Jim
JimsRebel@aol.com