My two cents on this are as follows:
The Rebel will not fall apart using nytrol nuts on everything, if installed
and maintained properly!
UNFORTUNATELY this is not legal under the MD-RA inspection program and some
of the AC-43 technical references.
I have never stated that drilled and cotters where necessary on wing attach
bolts and I think the only place this came up was when Mike Kimball was
looking for some new wing bolts for his Moose/SR cross and I had some here
that would of worked but were drilled. Normal -A bolts and Nytrol nuts are
just fine on anything that isn't moving (from Firewall back), such as wing
fittings, struts, stab, axle attach bolts, etc.
Technically ANYTHING that is working as a "pivot" or "hinge" MUST have a
drilled bolt/castle nut and cotter. Even though, as I stated above, the
landing gear legs have never loosened or fallen off my Rebel in 8 years (and
there is no reason that they would from the minimal amount the gear moves)
the MD-RA will NOT pass a final inspection on a Murphy Rebel that has
landing gear legs bolts installed using (the MAM supplied) nytrol nuts
and -A bolts. This was made VERY clear during our Ontario "RATASS"
(Recreational Aviation Technical Advisors Safety Seminar) workshops, so
clear in fact that Jamie Alexandre's presentation even had a slide of a
Rebel's landing gear legs using the "wrong" attachment hardware. If they
have gone to this length to "black list" this attachment practice then every
MD-RA inspector has seen this slide and it's clearly imbedded in their mind.
Murray, you have a good point in using them on the elevator control mixer in
the tail cone that converts cable to push pull. The cable attach bolts
aren't really rotating and the thimble will just rock on the bolt as it goes
back and forth, but why not be safe about the whole thing (and avoid a
possible snag with MD-RA).
As for the push pull ends, your call here. I will take the inspector to task
if he wanted me to change all of these to drilled and also any bolts holding
a bearing'd pulley in place. As long as the bearing or rod end pivot is
doing it's job the bolt is never going to rotate. AC 43 also clearly states
that a nytrol nut can be used on a bearing'd pulley and I have that paged
marked for the confrontation if it ever comes, but my book is out in the
shop and I'm not wading through the 20" of snow we got over the last 24
hours to go get it, so I can reference the sub section.
As for the engine mount bolts I'm not sure which ones you are referring too
so I will cover both.
The firewall to engine mount bolts could be either drilled bolts and castle
nuts, or -A bolts and METAL lock nuts. Murphy supplied drilled bolts and
castles, and probably for the reason to make sure that you don't strip the
threads installing the nut and then having a safety of a cotter pin through
so the nut couldn't tension pull off.
As for the mount to insolation rubber engine bolts, I am not sure what is
really "legal" here. On my Rebel I used the bolts that came with my original
PA-12 engine and mount. They were drilled, used castle nuts and pins. Every
motor I have installed since has been done using normal -A bolts and METAL
lock nuts. I have never found one that has loosened off from vibration in as
long as 7 years on an airplane but I don't know for sure if MD-RA would snag
this as only one with metal lock nuts has had to go through the inspection
process and that was back in 1996.
Hope that helps some!
Wayne
----- Original Message -----
From: "Murray and Carol Cherkas" <
cherkas@shaw.ca>
To: <
murphy-rebel@dcsol.com>
Sent: Sunday, February 23, 2003 9:13 PM
Subject: drilled bolts/castle nuts/cotter pin
Listen up everyone
If you haven't followed this thread, you should consider it.This is really
important.
WAYNE: you mentioned using castle nuts and cotter pins wherever there is
movement on a bolt as well as wing attach and engine mount.
Please comment on this. I just changed my bolts in the control horn in
tail
section and on push pull tubes on linkages.
Thanks again
Murray Cherkas
REBEL 505
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