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  #1  
Old 02-26-2013, 08:43 PM
tx_jayhawk tx_jayhawk is offline
 
Join Date: Mar 2005
Location: Olathe, KS
Posts: 374
Default Duckworks Lense Cracks?

I have the Duckworks lenses in the leading edge. WHile prepping everything for paint, I noticed that both lenses have cracks in all four corners where the al nutplate backing strip is. This after less than 2 years (were probably cracked before I even flew). There is a 9 on the field that has the same problem.

Anybody else experience this, and if so, what was the cause (and how did you prevent)? Also, any tips for installing a new lense in a previously installed wing that is dimpled?

Thanks,
Scott
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  #2  
Old 02-26-2013, 10:06 PM
Steve Barnes Steve Barnes is offline
 
Join Date: Jul 2008
Location: Santa Rosa, CA
Posts: 580
Default Me too!

Just normal stress mixed with airframe vibration. You can buy additional lenses at a reasonable price. Replace it on a nice warm day.

Steve
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  #3  
Old 02-26-2013, 11:47 PM
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LifeofReiley LifeofReiley is offline
 
Join Date: Jan 2005
Location: Round Rock, TX
Posts: 3,778
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Hey Scott,

Normal everyday thing... even ream oversizing and deburring does not seem to help much. Might still be from over tightening the screws Dunno.
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  #4  
Old 02-27-2013, 03:23 AM
s24789 s24789 is offline
 
Join Date: Jan 2009
Location: Hobe Sound, Florida
Posts: 292
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Our's had spider crackers after 20 hours. Lived with it until paint was complete and replaced. We did oversize the new holes and add foam the entire length of AL nutplate piece. Only time will tell. 30 hours and no cracks.
Phelps
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  #5  
Old 02-27-2013, 04:56 AM
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woodmanrog woodmanrog is offline
 
Join Date: May 2005
Location: Florida
Posts: 774
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These cracks usually happen from over tightening the screws. I added a thin strip of foam rubber between the metal and the plastic to relieve stress from a possibly to tight screw and have had no problem for 600 hours.
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  #6  
Old 02-27-2013, 06:16 AM
Sid Lambert Sid Lambert is offline
 
Join Date: Jul 2005
Location: North Atlanta
Posts: 1,120
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I think Woodmanrog is correct. If you add something like 3M outdoor mounting tape around the edges then it seems more resistant to cracking.

I did this by accident as I started just making my own lenses in the oven. The latest one wasn't bent exactly correct so I used some 3M mounting tape to hold it while I put the screws in. I just left the tape on and it's lasted about 550 hours. Before they were replaced every year.
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  #7  
Old 02-27-2013, 08:00 AM
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Steve N. Steve N. is offline
 
Join Date: Jan 2006
Location: Chapmansboro (TN77), TN
Posts: 107
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I had this happen also, but not at all the screw holes, at less than 100 hours . I replaced one lens then decided to wait and see what happened with the other lens that had cracks radiating from only one corner. 500+ hours later that has been no change.
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