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Problem with J-stiffener fit on bottom skin

bsbarnes10

Active Member
Hello,
I've seen a couple threads on this issue but none had any closure so I'm hoping someone with experience (or maybe from from Van's) can chime in...

My problem is that J stiffener F-1283B doesn't sit flush against the bottom right skin F-01282-R-1 when installed per the plans page 10iS/U-06

ad8a9a_06bf7997fbd249079bc4965da27fb010~mv2.jpg


I checked the corresponding part on the left skin (F-1283A & F-01282-L-1) and it fits right up against the skin as I'd expect.

ad8a9a_b4656ea9d86748a3bc676519130478d4~mv2.jpg


I checked the radius of the two J stiffeners F-1283A & B and they look to be identical

ad8a9a_53567f62da384808af53e02c08fc294a~mv2.jpg



Next I checked the radius on the skins (as measured by the distance from the holes on the web to the vertical portion of the flange) and the radius on the two skins is definitely different

Here is the offending right skin F-01282-R-1

ad8a9a_f59edae3e499438b83d68ab4f41a2ef9~mv2.jpg


And the correct (I assume?) left skin F-01282-L-1

ad8a9a_e1e985093c9c44a6a10f3e0efc865991~mv2.jpg


Another thread on this topic suggested the stiffener on the right skin should go on the OUTside of the skin and I agree the radius fits better but then the holes don't line up and the plans clearly show in figure 2 that the J-stiffener F-1283B goes inside the skin F-01282-R-1 for riveting.

Does anyone have any suggestions or experience here?

Also, on a related issue F-1284-R & -L seem to be mislabeled in figure 4 on page 10iS/U-03? The L / R designation shown on that page does not match the L/R orientation shown on page 10iS/U-06.

Any help or guidance would be greatly appreciated!

-Bruce
 
Last edited:
Im seeing the EXACT same issue on my build. Even down to the same measurements. Id love to get an answer on how to proceed.
 
Heard from Van’s

I just got a response from Van’s on this (thanks Sterling). They indicated it isn’t a problem and suggested I fabricate a spacer, match drill, and install two rivets. They also confirmed that F-1284L/R are mislabeled.

-Bruce
 
Tail cone J-Stiffiner gaps

I'm at this point in my build now. I have gaps between both the bottom left and right skin J features and F-1283 A & B J-Stiffeners. A .016" thick shim spacer will fill the gap on the left side and a .025" thick shim spacer will do the job on the right side. I can make both from practice stock sent with the empennage kit. Insertion of the shims will ensure accurate longitudinal hole alignment between the full length of the J-Stiffeners and the bottom skins.
My hat is off to bsbarnes10 for his clear explanation of the problem and the photos. This saved me from wasting time trying to sort it out on my own.
Overall, I have been continually amazed at the accuracy of the kit's part geometry and hole locations. This is a pretty minor hick-up. Love building this thing.
 
I'm glad this post was helpful and agree, so far everything else has matched up just about perfectly. I had a bit larger gap on one skin (about 0.039") while the other fit perfectly, or at least close enough I was comfortable snugging it up with the rivets. I ended up making the the shim from some of the 0.040" 2024 AlClad from the trim bundle.

Here is the gap:

UNADJUSTEDNONRAW_thumb_553c.jpg


The spacer:

UNADJUSTEDNONRAW_thumb_5542.jpg


And the spacer installed:

UNADJUSTEDNONRAW_thumb_5546.jpg


When I added up the thicknesses it looked like an AN470AD4-4.5 was a hair short and an AD470AD4-5 was a bit too long so erred on the long side.

-Bruce
 
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