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06-26-2012, 12:13 PM
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Join Date: Jan 2005
Posts: 1,009
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Vans absolutely needs to see this
For a couple of reasons...
The skin on your plane is structural. A few minor scratches, no problem. As already mentioned, they can be polished out. Anything that may compromise the integrity is another issue, and these appear to be more than superficial. Let Vans make the call, but at the least, ask For a written position.
Second, it would appear that one of their "quick builders" has taken it upon themselves to remove the film using a method harmful to the end product. Vans needs to be aware of this to prevent it from happening elsewhere. I'm sure using a sharp device is not something they'd approve of.
I think Vans has a great product, but they may need to address the level of control they have over their subcontractors. I'd be very interested to hear Vans response to these imperfections. Please don't rely on forum opinions to drive your decision in this matter.
Terry, CFI
RV9A N323TP
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06-26-2012, 12:16 PM
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Join Date: Jan 2007
Location: Battleground
Posts: 4,348
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Quote:
Originally Posted by Mel
But to me, that is totally unacceptable. A "scribe line" like that is just asking for failure.
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You are absolutely correct Mel, as usual. However, you would not believe the scribe lines I have discovered doing the restoration of my Fiat Spar Caps. Each Rib location was layed out by scribing a line right into the extrusion. This airplane flew for a long time and there is no evidence of any harm the lines caused. If I add this to the long list of other airworthy concerns due to workmanship on these Fiat's, they should have all fallen out of the sky. But they didn't.
I am diligently smoothing and fairing out the lines because that is the correct thing to do. Very little material will be lost in this example.
While I am not so sure about this RV Wing, I would not consider a complete reskin just yet...
...and yes, that is one person thoughts, not really even an opinion... Van's will not give you an opinion, they should however give you a path of correction or replacement.
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
Last edited by JonJay : 06-26-2012 at 12:22 PM.
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06-26-2012, 12:28 PM
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Join Date: Aug 2010
Location: Wichita, KS
Posts: 1,958
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While blending out the scratches completely alleviates the fatigue life concern, it does so at the cost of all other static properties. Tensile and shear strength, as well as compression buckling (if these were top skins) are all affected by thickness. Reduce thickness = reduce strength. Remember, you're not just concerned about this area today. What if hangar rash or some other event scratches this same area in the future, and you decide to blend it out....again. Significant thinning can occur, and without expensive equipment to measure local thickness, you really don't know what's left in each area.
Are RVs overbuilt? Yes. Should you give up the time and cost to blend these out yourself, the ability to have a polished wing, and future repairability all because someone at the QB factory was being stupid? Absolutely not.
__________________
Kurt W.
RV9A
FLYING!!!
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06-26-2012, 12:41 PM
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Join Date: May 2009
Location: Houston, TX
Posts: 531
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If those were direct from Van's I would not accept them.
If they had passed through other hands (which seems like might very well be the case) then...........well, I think I'd replace from the pics.
We really do need clarification on the history of this kit though.
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-Rick Greer, VAF #2492
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06-26-2012, 12:41 PM
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Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,573
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Calm Down!
Take a deep breath everyone!
While not a good practice, these scribes are probably OK.
Because:
Those scribe/scratches are probably a half a thousandth to a full thousandth deep, which is something like 3% or less of the skin thickness.
Remember that these skins carry almost entirely shear stress, and although they participate in carrying tensile load, they are not needed for that. The spar carries the load, its not like a stressed-skin structure on a big jet liner.
You could cut every panel of skin into separate squares with no splice overlap and still the wing would be strong enough to meet the design criteria.
So - yes, I would sand the scratches out, and then use a really good primer and paint to protect from corrosion. And I would not loose any sleep about the structural strength of the wings.
__________________
Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 625
LS6-15/18W sailplane SOLD
bought my old LS6-A back!! 
VAF donation Jan 2020
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06-26-2012, 12:45 PM
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Join Date: May 2009
Location: Houston, TX
Posts: 531
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Quote:
Originally Posted by scsmith
While not a good practice, these scribes are probably OK.
Because:
Those scribe/scratches are probably a half a thousandth to a full thousandth deep, which is something like 3% or less of the skin thickness.
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I still wouldn't accept construction techniques like that from the manufacturer. (We don't know if this is the case though.)
__________________
-Rick Greer, VAF #2492
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06-26-2012, 01:34 PM
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Join Date: Apr 2005
Location: KSLC
Posts: 4,021
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For curiosity sake, I'd take some gray scothbrite (type) pads, from Home Depot, auto paint stores, etc.........scrub with some soap & water, and see how the scratch compares. This is essentially what you do before painting.
L.Adamson
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06-26-2012, 02:04 PM
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Join Date: Nov 2009
Location: Littleton, Colorado
Posts: 269
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OP please reply - bought second hand from someone or from Vans?
Quote:
Originally Posted by L.Adamson
For curiosity sake, I'd take some gray scothbrite (type) pads, from Home Depot, auto paint stores, etc.........scrub with some soap & water, and see how the scratch compares. This is essentially what you do before painting.
L.Adamson
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So it would be nice to know if they were purchased second hand from another builder, or if they came from Vans. Agree that if from Vans I would not accept them.
To add to the above quote, after you are done comparing the scotch brite scratches to the ones shown in the pics, then take a brand new soldering iron with a flat blade tip, and without smoothing it out on a grinder or with some light sandpaper, take another test piece with the vinyl on it and run a line with the iron. Then strip the vinyl and look at the metal. I can just about garantee that there will be a scratch there. I have even had scratches form like this in a couple of places after I smoothed out the tip. So I am not a big fan of the whole strip-the-vinyl-with-the-soldering-iron club because it has not worked very well for me at times in the past.
Now compare those scratches from the soldering iron to the ones in the wings and see if they are the same depth, or if the wing scratches are deeper. If they are deeper than the soldering iron scratches then I would say that someone definitely took a knife of some sort to them, and that stinks. The issue, then, will be the depth of the cut, and what Vans says about it. I know that close up pics can really dramatize the way that certain imperfections can look on the metal, so I won't render a verdict on the wing scratches because IMHO it is just too hard to tell. Running some tests for comparison is a good way to go.
I had a different episode with a 6 inch scratch found on the web on one side of one of my wing spars, which Vans ended up telling me to dress out and prime. It was just deep enough to catch a finger nail, but not so deep that I thought I would need a new spar. Thus I contacted the mother ship and sent pics to them just to be sure.
Good luck.
__________________
Bryan Raley
http://bryansrv8project.blogspot.com/
Building RV8
EAA Chapter 301
CFII/MEI, ATP
SportAir Workshop Graduate x 4: Sheet Metal, RV Building, Electrical, and Composite classes.
Tail Wheel Endorsement Completed
Empennage done, Wings in progress, N462AK reserved.
Last edited by Flyin'Bryan : 06-26-2012 at 02:14 PM.
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06-26-2012, 02:05 PM
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Join Date: Jul 2008
Location: NorCal
Posts: 565
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Even besides the astonishingly bad practice at the QB factory in the Philippines, how did these pass inspection in Aurora??
I bought a QB kit and there was nothing like this. I doubt I would have accepted the kit with obvious poor craftsmanship. You pay a premium for a QB kit and should not accept this, regardless if it is structurally acceptable.
__________________
Ralph Finch
RV-9A QB-SA
Davis, CA
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06-26-2012, 02:12 PM
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Join Date: Jan 2007
Location: Battleground
Posts: 4,348
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I am pretty sure Van's does not leave the film on or work around it, but I could be wrong. I built my wings so can't compare and that was long ago. However, the RV3B QB wings came bare, no film.
Hmmmm.....
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
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