Today's Message Index:
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1. 06:50 AM - Wing attach bolts (BobbyPaulk@comcast.net)
2. 02:30 PM - Re: Wing attach bolts (Larry McFarland)
Message 1
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| Subject: | Wing attach bolts |
List
While finishing up my "Conditional" last Sat. I checked the 12 wing attach bolts
for the proper torque. I found the pilots side top two inside bolts to take
a good 1/4 to nearly 1/2 turn to get back to 144 inch pounds of torque. I could
see that the nuts had not moved because I had the orange inspection lacquer
on the threads. They were not loose on the last inspection ( 35 hrs. ago ) and
I have not been rough or pulling high G's. The rest of the bolts were in spec
and did not turn.
Has anyone else experienced this? What caused it and is it unsafe?
I would appreciate your input.
Bobby ( age 74 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 160 hrs.
Message 2
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| Subject: | Wing attach bolts |
Hi Bob,
The stretch during torqueing would be slight, but thermal effects, a
couple of .0002 seasonal material shrinkage and/or thread climb within
the fastener threads could have allowed
conditions to require more tightening. Or you might have gotten Chinese
counterfeits that have a compromised material strength. There are lots
of reasons, but you=99d
be more certain if you replaced the bolts and tightened those two
questionable bolts to failure to find out how much safety you have in
excess of the specified 144 inch-pounds.
The test might be enlightening and give you some comfort in having
looked at it closer. It might just save your skin too.
Fly safe,
Larry McFarland
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of
BobbyPaulk@comcast.net
Sent: Monday, October 08, 2012 8:50 AM
Subject: Zenith601-List: Wing attach bolts
List
While finishing up my "Conditional" last Sat. I checked the 12 wing
attach bolts for the proper torque. I found the pilots side top two
inside bolts to take a good 1/4 to nearly 1/2 turn to get back to 144
inch pounds of torque. I could see that the nuts had not moved because I
had the orange inspection lacquer on the threads. They were not loose on
the last inspection ( 35 hrs. ago ) and I have not been rough or pulling
high G's. The rest of the bolts were in spec and did not turn.
Has anyone else experienced this? What caused it and is it unsafe?
I would appreciate your input.
Bobby ( age 74 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 160 hrs.
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