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How old is too old?
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Pete Fowler

Joined: 07 Jul 2009
Posts: 76
Location: California

Posted: Sat Apr 24, 2010 12:42 pm Post subject: How old is too old?

While working on my plane at Santa Paula, one of the many A&Ps there happened by and was looking at my fuselage and said "wow, that plane must have been overstressed at some point". We sort of ignored that but since then I've noticed that my fuselage skins are more "wrinkly" from behind the back seat to the tail. Compared to the "Fresh Off Boat" one I saw today, that one had nearly perfectly smooth fuselage skins.



My plane is one of the first CJ-6s imported into the U.S. in 1991 and had an estimated 3500 hours when imported so now has something like 4900 hours on the airframe. I know that's nothing compared to most other planes but since it appears to be the (or one of the) highest hour planes around, it made me think.



Am I the "guinea pig" for Nanchang hours? How would I determine if the wrinkly skins are "normal"? The local Nanchang guys don't think anything of it but what do you guys think?

dsavarese0812(at)bellsout
Guest

Posted: Sun Apr 25, 2010 3:48 am Post subject: How old is too old?

I guess the question is, have you ever seen an  airplane fresh from the factory with wrinkles in the fuselage skins?   I've always believed they don't build them with wrinkles in the skins.   Even the home builts like the RV's don't have wrinkles or ripples in the  fuselage skins.  Doug may be able to shed some light on the  subject.

 Dennis

  

 [quote]   ---

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Sun Apr 25, 2010 2:55 pm Post subject: Re: How old is too old?

how about posting some pictures?

keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Sun Apr 25, 2010 2:56 pm Post subject: Re: How old is too old?

how about posting some pictures?

Pete Fowler

Joined: 07 Jul 2009
Posts: 76
Location: California

Posted: Mon Apr 26, 2010 4:05 pm Post subject: Re: How old is too old?

This is pretty hard to photograph. Here's one photo and a link to some more on line. What I'm looking at are the "dents" that are on the flat panels between the rivets. There is one set that run around the fuselage just in front of the horizontal stab. In the online gallery, you can click the photos to see them bigger. I've seen similar dents in similar locations one one side or the other on some Nanchangs but not in this quantity.



http://pictureposter.allbrand.nu/pictures/nasa+racer/Nanchang+tail/

P1000790.JPG

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keithmckinley

Joined: 11 Aug 2008
Posts: 434

Posted: Mon Apr 26, 2010 4:32 pm Post subject: Re: How old is too old?

Those "dents" always look worse with a sweet shiny paint job like yours especially when looking down the side like your photo. Your plane looks like every other CJ I've ever seen including my own.



Keith

alikatz(at)mbay.net
Guest

Posted: Mon Apr 26, 2010 6:38 pm Post subject: How old is too old?

I agree with Keith, I Honestly don't see a problem with the aircraft Pete..





Quoting keithmckinley <keith.mckinley(at)townisp.com>:



 	  Quote: 	
		   



 Those "dents" always look worse with a sweet shiny paint job like   

 yours especially when looking down the side like your photo. Your   

 plane looks like every other CJ I've ever seen including my own.



 Keith



 --------

 Keith McKinley

 700HS

 KFIT





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=295799#295799

n4829t(at)aol.com
Guest

Posted: Mon Apr 26, 2010 6:38 pm Post subject: How old is too old?

What year is your CJ?

---

n4829t(at)aol.com
Guest

Posted: Mon Apr 26, 2010 7:03 pm Post subject: How old is too old?

I have a 1962 CJ with about 4300TT... I have the same dents and have seen many others with the same. 



Does anyone out there have a 1962 or older?



Regs,

Jim P. 

---

Pete Fowler

Joined: 07 Jul 2009
Posts: 76
Location: California

Posted: Mon Apr 26, 2010 7:34 pm Post subject: Re: How old is too old?

Mine is a 1966 plane.

cjpilot710(at)aol.com
Guest

Posted: Mon Apr 26, 2010 8:40 pm Post subject: How old is too old?

CJ-6 production was started in 1962.  As far as I know there was only one CJ here in the US that was built in 1962.  It belonged to Jim Plumy I believe.

    

   Jim "Pappy" Goolsby

 

 

   

 

 

   --

bigdog(at)bentwing.com
Guest

Posted: Tue Apr 27, 2010 8:02 am Post subject: How old is too old?

I don't know CJ's but those "dents" look like spot welds.

 



[quote] --

N642K

Joined: 23 Jul 2008
Posts: 84

Posted: Tue Apr 27, 2010 8:32 am Post subject: Re: How old is too old?

My CJ has the same amount if not more.  The 737-300s that I fly routinely have way more.  Ever been up close to a B-52?  The fuselage will make you sea sick if you run your hands over it.



http://www.flyingsquadron.com/forums/index.php?/topic/16804-aircraft-fatigue-pictures-searching-for-b-52-pic/

barryhancock

Joined: 09 Oct 2008
Posts: 285

Posted: Sat May 01, 2010 10:24 am Post subject: Re: How old is too old?

Many series of productions used spot welding (not sure on the years, but it was later than 66, I think), but looking at the pic Pete provided it looks like rivets to me.  And it just looks like less than ideal riveting from a production line that was still learning the art. They did get better....late 60's were the prime production years for these airplanes.  I've seen a couple of new CJ's that don't look nearly as good from a sheet metal finish stand point as many more vintage editions...  That picture certainly doesn't denote something to be concerned about from a structural standpoint.



Happy Flying,



Barry

_________________
Barry Hancock
Worldwide Warbirds, Inc.
www.worldwidewarbirds.com

wlannon(at)persona.ca
Guest

Posted: Sat May 01, 2010 6:57 pm Post subject: How old is too old?

I believe spot welding on the CJ6 was introduced on 1969 models at the same 

time they started using alclad rather than anodizing.

They eventually went back to rivets and anodizing but I don't know what 

year.

Pre 1969 riveting was for the most part quite well done.  Far better than 

the few newer ones ( late 1980's) I have seen.

Another change that came in 1969 was the total elimination of fuselage 

frame/stringer clips. They probably determined that these were unnecessary 

with an airframe life limit of 4000 hrs.



Walt



---

Pete Fowler

Joined: 07 Jul 2009
Posts: 76
Location: California

Posted: Sat May 01, 2010 7:29 pm Post subject: Re: How old is too old?

Since you guys mentioned it, I went back and look and, sure enough, my 1966 is spot-welded on the rear fuselage panels where they're secured to the stringers but riveted where the panels overlap or are  over formers. It also has button head rivets where the formers "cross" the stringers.



http://pictureposter.allbrand.nu/pictures/nasa+racer/nanchang+tail/P1000788.JPG.html

barryhancock

Joined: 09 Oct 2008
Posts: 285

Posted: Sat May 01, 2010 8:03 pm Post subject: Re: How old is too old?

That's a better shot, Pete.  Yup...wasn't sure when they spot welded....good to know.  All the more reason for the "wrinkles" and it's highly likely you have nothing to worry about here as it relates to structural integrity.  Besides, this being Kilo's former bird, I'm sure it never saw more than 4 G's...he getting along in years and such...

_________________
Barry Hancock
Worldwide Warbirds, Inc.
www.worldwidewarbirds.com

barryhancock

Joined: 09 Oct 2008
Posts: 285

Posted: Sat May 01, 2010 8:10 pm Post subject: Re: How old is too old?

Now, getting back to that "A&P's" comment that stirred all this up....just more proof that a title doesn't necessarily correspond to any expertise....it makes me mad when people make uneducated comments, borne out of whatever motivation, especially those that create unwarranted worry or doubt.  It doesn't do anyone any good...I guess I'm just tired of these airplanes being under appreciated.  After working with and flying several ex-eastern bloc types from props to jets, they deserve more respect than they typically get.



Happy Flying,



Barry

_________________
Barry Hancock
Worldwide Warbirds, Inc.
www.worldwidewarbirds.com

wlannon(at)persona.ca
Guest

Posted: Sun May 02, 2010 9:46 am Post subject: How old is too old?

Hi Pete;



What is the serial number of your CJ?  Of the four I imported from China in 

1994 two were from batch 15 (dated Dec 65 and Jan 66), one from batch 24 

(dated 1968) and one from batch 25 (dated 1969).

Only the 1969 model was spot welded.  All four were produced by factory #320



The first two digits of the serial no.is the batch number which will give an 

indication of when it was manufactured.



Hey Doug,  I'm sure you could shed some light on this subject.  When did 

spot welding of CJ fuselage skins start and end?



Walt

---

Pete Fowler

Joined: 07 Jul 2009
Posts: 76
Location: California

Posted: Sun May 02, 2010 2:17 pm Post subject: Re: How old is too old?

Serial number 1832039

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