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Little ripples in side skin.

Fl Mac

Well Known Member
When I look down the side of my tail, I can see small ripples in the center skin. You can not see them when looking straight on or even at a larger angle, but you can see them when you look from a small angle from the front.

Should the center side skin be smooth from any angle you look at it? Am I being too picky?
 
Ripples

I just went to the store room and looked at mine and I could see no ripples. Mine still has blue plastic on, maybe that covers them???

Bill
 
Some of the wrinkles will come out when you join the fuse and the tail cone togeather. Have you done that yet?

The way Scott at Vans told me this is the "8N of airplanes." (8N being an old Ford tractor, ugly, but it worked hard.) It's gonna have some "beauty marks" on it.
 
I have noticed that my empennage skins are not perfect either. But I think we have to remember that in the bare aluminum every little reflection shows up. I'm thinking when the airplane is painted it will look fine. Also - there is the "I built it" factor. You and I will always be able to see the tiniest defect, because we know it is there. Others will think it is beautiful!
 
Some of the wrinkles will come out when you join the fuse and the tail cone togeather. Have you done that yet?

The way Scott at Vans told me this is the "8N of airplanes." (8N being an old Ford tractor, ugly, but it worked hard.) It's gonna have some "beauty marks" on it.


No, I have not joined them yet. I am a little behind you guys. The tail is done, the Wing kit arrived today, and fuse will be next.



I have noticed that my empennage skins are not perfect either. But I think we have to remember that in the bare aluminum every little reflection shows up. I'm thinking when the airplane is painted it will look fine. Also - there is the "I built it" factor. You and I will always be able to see the tiniest defect, because we know it is there. Others will think it is beautiful!

That is what my wife said. When I said I was not happy with the ripples she said "what ripples". When I pointed them out she said, "you are the only one that will care about them".

I guess I will move on and start the wing today.
 
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Glad somebody else noticed. The ripples are sort of an eyesore, especially after all that careful work. The ribs don't extend far enough and pull the skins in slightly.

Rick.
 
"little ripples"?

My side skins will actually oilcan if I reach into the tailcone and wiggle the frame back and forth. You can see the ripples from certain angles and not from others. In this picture my skins look great but they do have the "ripples".
493308542_HExC5-L.jpg

I thought at first that I might have not riveted in the right sequence or something, but I was very careful to follow the plans for when to rivet what. Then I realized that the frames put little if any curvature on the side skins, and the curvature, like the top side skins have, would eliminate the ripples. So it is a design characteristic. It does look like the attachment of the fuselage would tend to add in some curvature, so I am hopeful that might help the situation. Anyway, it is not a big deal, I like my airplane so far.

Tony
 
Wait until you get it attached to the tail feathers and fuselage and all the forces pulling at it this way and that....you'll see some real "waves"....this is pretty thin skin as you have noticed...helps keep the weight down while still being engineering to fly safely.

The wings in my Comanche quivered everytime I touched em but in the air they would take a beating and keep on ticking.

I'm more concerned how this flies than how it looks. If it was looks I was after I would be saving for Gulfstream.

I think a year from now we will all be proud of ourselves for taking this educated risk.
 
We have some oil-cans on the side skins of our empennage, also. I didn't flute the fuselage bulkheads and thought that the pre-loading may have contributed. The most annoying part of this issue is that every guy that has done any metalwork comes into the hangar and rubs his fingerprints all over the spots and tells us how to get them out. Shims, doublers, and judicious use of a hammer have been suggested. I'm with "BigJohn", paint it and it will look fine.

GDS
 
Tailcone Oil-Canning

I, too, have been having some oil-canning issues on the tailcone. The left is better than the right and the F-1209 frame is better than the F-1208.

After putting a straight edge on the F-1280-R skin, I have a 7/32" depression, at the deepest, just aft of the F-1208-R fuselage frame. It is probably 6" across and 8-9" high. I drilled out the 7 vertical rivets on the F1208-R frame and the depression lessened to 1/8" with the skin floating off the flange.

Van's recommended shims or stiffeners since the void would be too large to fill. When I asked whether the use of shims and a stiffener would impact the E-LSA status, I was told that it would not.

I plan to follow Van's advice, but I am going to wait until I cleco the fuselage onto the tailcone to see what else happens. Maybe I'll get lucky.

Joe
 
Yes, the oil canning is worse on the right side of my tail cone also. This is great news, that we can correct this problem. Would be easy to access before attachment to the fuselage...

Rick.
 
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I, too, have been having some oil-canning issues on the tailcone. The left is better than the right and the F-1209 frame is better than the F-1208.

After putting a straight edge on the F-1280-R skin, I have a 7/32" depression, at the deepest, just aft of the F-1208-R fuselage frame. It is probably 6" across and 8-9" high. I drilled out the 7 vertical rivets on the F1208-R frame and the depression lessened to 1/8" with the skin floating off the flange.

Van's recommended shims or stiffeners since the void would be too large to fill. When I asked whether the use of shims and a stiffener would impact the E-LSA status, I was told that it would not.

I plan to follow Van's advice, but I am going to wait until I cleco the fuselage onto the tailcone to see what else happens. Maybe I'll get lucky.

Joe


I am experiencing exactly what you describe. I have drilled out those rivets and get about the same void. I will do the shim thing when I get the fuse done.

Thanks to everyone who commented on this issue. I really thought it was only me and it discouraged me after I got the tail kit done.
 
Is anyone getting any oil canning in the vertical stabilizer? My skin seems to be popping in and out above and below one of the ribs.
 
There is a lot of oil canning on the 7 when in flight. I saw a post recently with pictures. Search it and maybe you can find some causes/ solution.
The 7 is much more discussed than the 12 at this point. I know they are not the same planes, but both are aluminium and from the same designers.
 
Little ripples in side skin

I also have oil canning in the side skins in the vicinity of frame 1208. How much shimming will be required? I think I will wait until the Tail Cone and Empennage are attached to the Fuselage as this will change the load on Tail Cone for better or worse and perhaps Van's will have a standard fix for this condition.
 
oil-canning right side

I got tired of looking at it, so I drilled out about 10 rivets. Popped right out. I shimed a bunch and now it is fairly decent. The largest frame seems to be a little narrow at that point, or the skin is too large. I think the frame was too narrow. Glad I did it. One less thing to have people ask about.

John Bender
 
Not right now

I am fiber-glassing the canopy. I used the flanges cut off the wing ribs that I had kept in a nice pile. I just cut the widest surface off and that made about 4" strips. I drilled a 1/8" hole near one end of several, then went inside the rear and clecoed from the inside. I took the cutters in with me, and put enough in places to make it tight, clecoed from inside thru the one hole, then pushed the free end in line with the frame. When it felt tight, I went back outside and looked at it. When I got it where I wanted it, I match drilled from the outside thru the holes that were not drilled and clecoed from the outside. Then went back in and removed the clecoes, and went back out and clecoed from the outside. When it all looked good, I final riverted it. Long story, but it worked. Will try to get a picture in a few days.

John Bender
 
Yes but... Until Van's posts a "standard fix", how does correcting this issue impact ELSA certification? Would this fall under "workmanship". Any thoughts?

Rick
 
Fix addressed in earlier message

Yes but... Until Van's posts a "standard fix", how does correcting this issue impact ELSA certification? Would this fall under "workmanship". Any thoughts?

Rick

There is an earlier message in this thread indicating that Van's suggested the shims to at least one builder and already indicated this would not impact E-LSA certification.
 
I hope to rivet the tailcone next week. From the earlier postings I understand to use shims for the F-1208 fuselage frame only and just for the F-1280 L&R skins. Has anyone pictures of this how it was solved and the approximately thickness of the shims?
(Otherwise I leave them just clecoed).

Thanks, Joeri.
 
I'm on the ragged edge of ordering the RV12 kits so I'm dealing with my lingering concerns about the airplane (I don't have access to an actual airframe) -

Is the oil canning indicative of the overall RV-12 structure? Is the downside of 2 x 220 lb adults + 50 lbs baggage + full fuel an exceptionally light and tinny airframe? I've heard the tail assembly described as very flexible prior to joining to the fuselage. I'm concerned about vibration and overall durability especially after several thousand hours of occasional turbulence and hard landings. How does the structure compare to other RV types? (I've often thought I would gladly sacrifice 50 lbs of baggage for a stiffer airframe. )

I'm embarrassed to ask such questions given the outstanding reputation of Van's Aircraft but in the final analysis it's my $60,000 and backside on the line.

Hopefully, the consensus will be the airframe is just fine.
 
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My 2 cents

It is not a 'tank'. .020 material generally used on the skins is thin. Would not take much to put a dent in it. The advantage is lighter weight and more carrying capacity. That is the trade-off. I would not worry about long term. Inspect it regularly, and with 12,500 strong rivets, it won't fall apart very likely. Pilot mistakes are a much larger factor than the construction of this plane in my opinion. Its a light plane that should perform well if you understand what light planes feel like. I think the RV-12 will hold its value as well as any LSA type aircraft. Had a friend today ask if I would consider helping him build one down the road. Said I very well might be willing to do that.

John Bender
 
A few more thoughts

I agree with John. I wanted to specifically comment on what you have been told about the tail assembly. It is not flexible at all prior to attachment to the tailcone. Once the skins are on, the VS, rudder, and stabilator all seem to be very stout. The spar box on the stabilator is particularly robust. Yes- the skins are thin but I have to trust the Van's has done their engineering homework regarding what is necessary for structural integrity.
 
I agree with John. I wanted to specifically comment on what you have been told about the tail assembly. It is not flexible at all prior to attachment to the tailcone. Once the skins are on, the VS, rudder, and stabilator all seem to be very stout. The spar box on the stabilator is particularly robust. Yes- the skins are thin but I have to trust the Van's has done their engineering homework regarding what is necessary for structural integrity.

I believe William said the tail cone was flexible before it was attached to the fuse. I agree the control surfaces and VSare stout. The tail cone is flexible. I am a little disappointed in the tail cone ribs not having the proper radius and needing a shim. I think the shim should come from the factory cut and bent to the right radius.
 
Oil canning fuselage

I have just about finished the tailcone and noticed that I have significant "oil canning" at the F1208 frame. I drilled out a bunch of rivets on the frame, which relieved alot of the oil canning but not all. I thought about shimming, then brought the manual upstairs to re-read, to see if I did something out of sequence to cause it. It seemed that I followed the plans correctly, so I searched "oil canning" and found this thread.
I will shim today and move on.
 
We added shims, built it up ~3/16" with scrap Al. It improved the oilcan somewhat, probably wouldn't take the time if I were building a second RV12.

I'm very confident in the airframe, and even with a couple of oilcans in the tail, it's cleaner than most store-boughts. Everything goes together without forcing; if the parts don't go together smoothly, you put it together wrong. I wouldn't want to land it hard enough to set off the ELT, but I am not concerned about flying it in a little turbulence and doing normal bang-around mountain landings. I'd have even more confidence if there were hundreds of thousands of combined hours on this model, but that would take all the fun out of it.
 
I'm glad that I'm not the only only person who has had this happen. My "oil-canning" is limited to only the first forward section and I expect it to be eliminated when it is connected to the fuselage.

If I had to do it again, I would use three saw horses during the initial cone assembly (while upside down). I have a suspicion that there may have been some undesirable flexing occurring towards the first bulkhead.
 
Hey Tom

Sorry to say, I think you will still have the problem once you connect the fuse to the tail cone. You likely will have to shim it on the right first section. Seems to be a problem with the largest frame in that area. If you just get with it, you can shim it out in a couple hours of careful work. I used the trimmed off pieces of the wing ribs for shims.

John Bender
 
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I finished the tail cone this weekend :D and I also have the ripples and oil canning. While I am waiting on the wing kit, I was wondering if I could get some suggestions on whether I should just let it be for now or if I should shim it up. Also, if some of you have used shims, could you give me some suggestions on how this is done.
 
The oil canning in my tailcone went away when I joined it to the fuselage. I would let it be for now.

I am undecided on shimming later to relieve the minor ripple or indentation by the bulkheads - not sure it is that important to me and it could bring back the oil canning, but either way I don't think I would have gotten the shimming correct without the tailcone joined to the fuselage.
 
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Little ripples in the side skin

Sounds like a song once heard.

This is from the man himself. Van told me at Sun n' Fun that you can eliminate that condition by adding some of that extra angle stock left over from the kit and applying it inside the Tail Cone with some two-sided tape or glue to reinforce those rippled areas. The fix is not permanent and can be removed if someone objects. There will only be a slight weight and balance change depending on how many pounds of aluminum you use. Jusy kidding.
It should be only a few ounces.

Art Pennanen
 
Oil Canning

G'day fellow RV-12 builders and particularly flyers, as you may have the answer to my question. I have oil canning in the F-1280 Left and Right Side Skins exactly as described by Joe (sys1jal) in this thread.

It has been more than 6 months since the last post on this subject and in the meantime many more 12s have been completed and flown. So what have you who have gone before us experienced with this issue?

Does joining the tailcone and forward fuse diminish or remove the problem?
Has anyone tried shimming the sides of the F-1208 Frame and, if so, did it work?
Does the gluing of foam or angle inside the affected area work?
Is it just accepted as part of the weight trade-off?

I'd sure appreciate any assistance and advice. It's a real bugger (as we say in Australia) when you go to some lengths to get a good fit and finish on the project but the design or kit execution lets it down.

Dennis Mitchell
Canberra Australia
Empennage finished
Wings under way
 
I am glad you brought this thread to the front. I just completed my tailcone, and was alarmed to find oilcanning on both sides, both at the same front to rear location, after I was so careful with the assembly. On mine the oilcan is a slight depression on each side, that with finger pressure on the inside reverts to straight sides. I think I could glue a short piece of aluminum to the inside and eliminate the depression AND the oilcanning, that might be noisy in flight. In fact that may well be a great idea regardless. Would that ProSeal not work well on that?
 
You can shim till the cows come home...but you may want to fly?

We flew our 12 first on July 18, 2010 and today we went over 250 hours. There has been different amounts of rippling on the right side skin since day one and it will probably always be there. It actually is better in hot weather. The RV-12 operates beautifully...and I just can't see any ripples in flight.
Maybe that's because I can't see past my 'grin'?

I have never seen an RV-12 without a ripple; never expect to see one.

Jay Sluiter
N124CS
Albany, OR (S12)
 
Little ripples in side skin

As I clecoed the side skin before riveting I noticed the ripples so I shimmed the skin as I had to do a lot of shimming while building the RV-4. Looks good.

Ted Farmin
CFI RV-4 2007 550 hrs
Sonerai 1977
RV-12 -emp, wings done
 
RV12AtPaintShop


Following up on my post of March 2009, the RV12 is in the paint shop. I shimmed the worst offender and it looks somewhat better, but you can see a disturbance where the shim is placed. The oil cans I did not shim are still there, but the paint made them look shiny and pretty. I'm sticking with my original thoughts, paint it, fly it and forget about it.

This is my first photo post, sorry in advance if it doesn't work too well.
 
Made picture visible.

You took the link in the "address bar", that will not work. You have to right click on the pictue and copy that address.

IMG_5152.jpg
 
Dent in side skin from oops from bucking bar

Hello all !
I figured my question would best be suited in this thread. I was riveting my rv10 tailcone top aft skin last night and I slipped off with bucking bar and creates a small dent. Here is close up picture. Rubbing your hands over it frels
Like a braille sign. It’s killing me especially since everything is perfect except this.
Any ideas to fix. Any assistance will be nice:)

PS this is at the 1008 bulkhead just above right side skin and top aft skin seam….. it’s a huge eye sore��������
 

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John,
I’ve seen paint less dent repair people, with their special tools, work miracles on dents if they can get to both sides. The one I used his information came to me through a body shop I used in past. Of course round dents from hail are not as tough as those with sharp edges but they can do a lot. Good luck!
 
OK, thank you for your information I appreciate it… Yeah, I’ve played around with a couple issues on my automobiles over the years with hail dents, and other issues with car dents but being this is a air frame and structural integrity is paramount…I figured I would ask and see what others thought of this particular issue.

It is really not that bad. The picture does not do the minimal amount of damage justice. I am almost positive that some filler compound or aluminum repair prior to paint ball. Cover up it completely.

Blue skies. Take care, John Wayne.
 
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