Tailcone Bulkhead and Skin Interference

Not sure if anyone has come across this, or if this is just something that exists in every kit and should be ignored, riveted and not worried about.

I am at the step where you put the tailcone bottom skins on sawhorses and cleco the bulkheads to them.

The picture here shows the F-1208 bulkhead frame where it clecos into the two bottom skins of the tailcone. In the boxed area, you will notice that the flange of the bulkhead sort of overlaps one of the skins, rather than fitting nicely into the cutout. It would require more than just filing, but rather significant removal of material to enlarge that cutout in the skin and make room for the flange to nest in there. I don't know why that cutout wasn't enlarged as 2 out of the three bulkheads have this overlap and the third has a cutout where the bulkhead nestles perfectly in.

My gut reaction is to just leave it and rivet it together. The hole is far enough from the edge that everything should suck up fairly tight in there.

Anyone else at this stage of contruction that can take a peek at their tailcone?

Thanks so much
Steve

double check?

Steve,
It's been too long to remember and my empennage is closed up so I can't be much help other than to suggest you double check you're using the right parts and orientation of them. The area you describe doesn't look "right" in the pic, but you're correct, it may pull in OK if they are the right parts.
Let us know what you figure out.
Best Regards,
Dave

Like Dave it was a long time ago I did this, but what I will always say: if VANS parts don't fit you are doing something wrong.

Rich

What does it look like when it's clecoed together?

Jim

DaveWelch said:

Steve,
It's been too long to remember and my empennage is closed up so I can't be much help other than to suggest you double check you're using the right parts and orientation of them. The area you describe doesn't look "right" in the pic, but you're correct, it may pull in OK if they are the right parts.
Let us know what you figure out.
Best Regards,
Dave

Click to expand...

Dave,

Thanks.... They are definitely the right parts and the orientations are correct. It is something that normally would never be noticed, because that parts all slide together and fit fine. There is just an overlap there. I have sent an email to Van's inquiring about it. My guess is that it is just how it is designed and when riveted will likely look totally fine as there are other skin sections where similar overlaps occur. It just caught my attention because there is a factory cut relief notch for a J channel there. If the relief notch had been cut larger, it would have made room for both the J channel and for the bulkhead flanges.

I'll wait to hear what they say!

Thanks for the feedback,
Steve

RFSchaller said:

Like Dave it was a long time ago I did this, but what I will always say: if VANS parts don't fit you are doing something wrong.

Rich

Click to expand...

Vans builds a great kit and for the most part things do fit very well. With that said, I've already come across several parts that didn't "fit." After discussion with Vans including pictures, it became very obvious that they were defective. To give credit, they have been really good about the replacement of parts even several years after the purchase of the kit as there was no way during inventory to know that the parts would not fit. The only way to figure it out was during actual assembly.

My hunch is that this piece was just designed this way and the overlap is present on all RV-12 aircraft as long as there was not a parts change or modification. I have an email into tech support and hope to have an answer soon.

Steve

I do not remember if this is the area that I had issues with during the build, but I do remember shimming several places and particularly with the tail cone attachment to eliminate outer skin deforming. When pulling that rivet shown in picture, the gap closure will not all come from the inside. You will have an unsightly dimple without shimming. In places I recall staging varying thickness of shims along multiple rivets for smooth transition.

Shims yes, but what kind?

skydiverlv said:

I do not remember if this is the area that I had issues with during the build, but I do remember shimming several places and particularly with the tail cone attachment to eliminate outer skin deforming. When pulling that rivet shown in picture, the gap closure will not all come from the inside. You will have an unsightly dimple without shimming. In places I recall staging varying thickness of shims along multiple rivets for smooth transition.

Click to expand...

Fully agree Larry. As I look at the outside now, I have a small number of places where the skin "pulled in" despite my best efforts to wiggle, cajole, cleco, and clamp it all tightly together. If I were to do over, or do it again, I'd make up some shims of scrap material and place them where needed to avoid the "house of mirrors" effect.