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The gotcha dimples in the VS skin.

RandyAB

Well Known Member
So despite the warnings abound about the nose ribs denting the skin on the vertical stabilizer skin, and despite grinding the nose ribs down to what it appears others have done (about 1/8") I managed to get a bit of dimpling particularly the middle rib. The outward dimpling remains after removing the skin following the match drilling. It's not huge but noticeable to me.

I was wondering if there was a way to remove them or should I just accept what is and move on?

Cheers!
Randy
 
Dimple

Don't know that there is any good way to remove that dimple (without replacing the skin) but believe me, there will be many more areas that will be nearly imperceptible to others and drive YOU nuts.

You just need to decide how many times you want to rebuild something before it is good enough...

NO ONE has built a perfect airplane...everyone has their "less than perfect" areas...:D
 
I had the EXACT same issue. Being a little OCD :), it drove me crazy, until I finished the VS. Now, I don't even notice and no one else (other builders or tech counselor) has noticed.

Accept it's not perfect and move on. I did better grinding edge off of Horizontal stab unit (with same warning about ribs) and no dents.

Too bad we can't build an entire plane "just for practice". :D The 2nd time doing anything is always easier.
 
Thanks boys. That's what I thought. I'm understanding from starting this that it is important to pay attention to good workmanship, but that if one gets too OCD then the pace of work will make completing the project a very distant dream if not an impossibility.

This is but a small problem. The thing that PO's me is that it's a well documented gotcha. Until the skin is in place though it'd difficult to tell if you rounded the ribs enough and by then it is too late.

One thing I had considered was centering a bucking bar behind and giving it a short couple taps with a flush face rivet gun. I don't know if that's been tried before but it sounds plausible to me.

Randy
 
One suggestion.... I did get a small "dent" on a skin from laying it on something on my work bench. I took a hardwood block of wood for the back "bucking bar" and a smooth brass hammer head to the dent side and simply pressed on the dent against the wood. Seemed to work good for me. I felt is was more forgiving than the rivet gun pounding on it.
 
Ya, that's another thing I learned very quickly.....keep the workbench clean. Now I see why people put a light carpet on theirs. I think I will do the same.

I don't think I'm going to sweat this much. I think I will be the only one who notices.

R
 
This is one of those things that only other Van's builders would notice. And just about all of them will ask you if you had the problem.. Mostly because they did the same thing!

I know I ground down my nose ribs and still have the dimples.. hah

At this point I see it as a right of passage =)
 
Told vans

I emailed Vans about this issue as I think it's a pretty big deficiency in the plans. They said its in section 5 (is that right?), but I don't recall seeing it. It gets most people, in my view it needs to be mentioned in section 6
 
Thanks Jason. I find your Youtube videos very helpful! Keep up the good work! :)
 
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I emailed Vans about this issue as I think it's a pretty big deficiency in the plans. They said its in section 5 (is that right?), but I don't recall seeing it. It gets most people, in my view it needs to be mentioned in section 6

It's not mentioned at all in Section 6. I think it would be a nice addition to the plans. I think it would be nice if there were a more explicit guide as to exactly how much of the rib to remove. My guestimate of about 1/8" as per other builders was just a tad too conservative.
 
I emailed Vans about this issue as I think it's a pretty big deficiency in the plans. They said its in section 5 (is that right?), but I don't recall seeing it. It gets most people, in my view it needs to be mentioned in section 6

It's definitely in there
B183625A-2690-43E4-B2D4-301033041037.jpg


Like some others, I was aware of it, ground off an amount to where I was beginning to worry about the flange material becoming too thin, and I still got some slight outies. Drove me nuts initially - thought I'd rebuild the VS at some point because of them. Several years later, I can't even notice them.
 
I had a similar experience but I read and re-read (several times) the part in section 5 about this issue and I still ended up with small dimples. It makes me feel a little better knowing that so many others have the dimples too even though they knew they needed to shape the nose ribs some more.

PS - If you haven't dimpled the skins yet, be careful with the holes closest to the leading edge (these were the dimples I thought the thread was about when I saw the subject). I used the DRDT-2 with the male die on the bottom and ended up bending the skin a little around those holes. I think putting the male die on the top so that the skin wasn't flexed so much around the top of the DRDT may have prevented this.
 
Has anyone had the guts (or crazy enough) to give the protrusion a nice controlled whack with some something spherical to dent it in, then fill it with bondo or something like it? This crosses my mind daily when I look at my two protrusions.
 
Uh, no

I'm guessing if you gave it a whack you would end up doing more damage than good...this is experimental, though, so if you give it a try make sure to post your results!:D
 
Just did the same **** thing …

I just wrangled the skin (carefully) onto the skeleton and while I ground the ribs down, the middle rib is showing a rise, not sure if it's a permanent dimple.

Is it worth it to take it apart and take more off of the nose rib?

Tough to see in the photos, but if you rub your fingers over it, you can feel the pressure from the rib on that point causing it to raise the skin a touch.
 

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Has anyone had the guts (or crazy enough) to give the protrusion a nice controlled whack with some something spherical to dent it in, then fill it with bondo or something like it? This crosses my mind daily when I look at my two protrusions.
Once a skin has a protrusion, the skin is stretched and a tiny bit thinner in that region. It's hard to make it shrink back to its original size. Also, aluminum is very flexible and only after you get past the end if its elasticity, will it change shape permanently but that also gets you close to the region where it will develop a crack. It's best to just leave the blemishes alone and live with them.
 
I came to the conclusion I’m never going to finish this aeroplane worrying about every non perfect thing. Whizz on down to the local airfield and check out a Cherokee or Cessna. In fact, even the Airbus 320’s I fly have imperfections all over them. Makes me feel better on my walk arounds.
So the ribs would have to be ground a long way down to prevent this. Why? The skin is under a lot of tension, held up at both ends by ribs so that nose rib is doing it’s job keeping the middle in shape. If you…like I…. Keep fiddling the rib gets shorter and shorter trying to ensure the bend from the web to the flange is not “sharp” a sure recipe for cracks to appear. So you round that part to ensure the rib has no sharp edges. Also the faceting instructions show a little ground off area when in fact looking at any nose rib on a compound curve is less that flat after punching and bending. They look better after dimpling.
 
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Try fluting

I didn't like the idea of grinding those flanges back too much and having an edge distance problem with that first rivet. I did grind them back some but also fluted the rib web ever so slightly to narrow the distance between the flanges. Helped to eliminate the faceting in the skin.

https://drive.google.com/file/d/1R_hMkQurEAxwgjh_RfbU0R5vflHu5v8-/view?usp=sharing

After all that, I later ended up dimpling an extra hole where I didn't want it and had to replace the VS skin once anyway :)
 
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