Recovering 140 wing

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Recovering 140 wing

Post by 8342 » Thu Aug 15, 2019 4:40 am

Hi All,

I am in the process of recovering the wings on my 140 and need some advice.

The first question is about the rivets used on the nose ribs.
It looks like they were originally spot welded and then AN430 (round headed) rivets were installed at some unknown point.
It was last recovered in 1974, so who installed them and when is anyones guess.
I am also missing the original logs but have them starting in 1956.

The question is can I replace the round headed with countersunk rivets to smooth out the leading edge?

The rest of the wings are in very good condition except for some minor corrosion that is easily corrected.

Thanks,

Rick

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Re: Recovering 140 wing

Post by 6643 » Thu Aug 15, 2019 8:19 am

Rick:
It's been about 25 years since I covered a set of wings, but, there are several service bulletins that were issued early on (1946 or '47) that pertain to modifications to the wing and its cover. One of them refers to the rivets you're seeing. (SLN 42)

That said, you should be able to substitute AN426 rivets as long as you can accomplish the necessary dimpling. (I have a set of dimpling dies that you pull together with a pop rivet tool.)

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Re: Recovering 140 wing

Post by 8342 » Thu Aug 15, 2019 11:59 am

Thanks John.

I have SLN 42 you mentioned but they talk about replacing cherry rivets with AN-456-AD4 rivets.

I have the 120/140 Reference manual put out by the Association and cannot find any more on the subject.

I am not seeing anything about using countersunk rivets.

Thanks for the offer, but I have dimpling equipment available.

Rick

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Re: Recovering 140 wing

Post by 6643 » Thu Aug 15, 2019 12:09 pm

8342 wrote:
Thu Aug 15, 2019 11:59 am
I have SLN 42 you mentioned but they talk about replacing cherry rivets with AN-456-AD4 rivets.
Maybe there's an earlier one discussing repairing or replacing spot welds with rivets. (Try 36 and 37). I recall there are several ADs and a handful of SLN's you have to wade through when you cover the wings.

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Re: Recovering 140 wing

Post by 8342 » Fri Aug 16, 2019 3:09 am

I finally found a reference to countersunk rivets in the leading edge.

It was in one of the the technical drawings associated with SLN 42.
It mentions "some may have countersunk rivets in them.
The way I read it countersunk can be used to attach the nose rib but you still need a regular rivet in place of the cherry rivets that may have been installed with the Service letter.

I will keep digging for more info.

Thanks,

Rick

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Re: Recovering 140 wing

Post by 8342 » Fri Aug 16, 2019 1:34 pm

Next question.

When I took the fabric off of the wings there was no lace going crosswise between the ribs.

Was it omitted or not required for the 140?

Thanks,

Rick

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Re: Recovering 140 wing

Post by 4004 » Sat Aug 17, 2019 1:43 am

I typed a lengthy reply but it failed to go thru and too late to retype - I'm slow keypuncher.

Thus, succinctly, check AD47-06-02 FAA promulgation applicable if serial number in range. In additions, Stits said, repeat OEM or if in doubt, install inter-rib bracing lacing.

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Re: Recovering 140 wing

Post by 8342 » Sat Aug 17, 2019 4:05 am

Thanks Edd.

Rick

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Re: Recovering 140 wing

Post by 6643 » Sat Aug 17, 2019 7:53 am

My understanding (not to be taken as an absolute) is that Cessna did not originally use bracing tape. Since the ribs are riveted to the spars it's unlikely they will shift while covering. Also, there is no mention of reinforcing tape in the parts catalog. That said, mine had it so I re-did it when I covered them. If someone has a drawing of the wing structure we could be sure...

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Re: Recovering 140 wing

Post by 6298 » Sat Aug 17, 2019 6:40 pm

I have recovered several sets of wings, and never until last week, have I seen rib bracing in them. I picked up a set of 140 wings and they had the nylon rib bracing. Still trying to research the AD Big Edd referenced. So far I have came up with a retractable landing gear placard under that number.
Randy Thompson A&P IA Pilot
Hold STC SA547EA for installation of O-200 engine in Cessna 120/140 and 140A"s
Overhaul small Continentals

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