Horizontal Stabilizer - Rear Spar Hole Misalignment

[Dennis Harm]

Talked to joe at vans, sent a new rear spar and doubler with rivets. Spar has no holes drilled for skins. Will reattach in a few weeks then on to tail cone.

[JDBoston]

Maybe this is a question for Scott if he sees this: is this a systemic problem with this set of parts in certain kits or builder error? I have tail kit 152 which was shipped with the wings and is still in the crate and I started on the wings first. Is there something that we can do to determine this quickly so we can start the replacement process? I have seen this issue described a few times now from builders with kit numbers earlier and later than mine.

[Tilford]

Hi Dennis,

I also had a misalignment with the HS rear spar, however, I determined that I had somehow introduced a twist in the HS during assembly. The twist was not obvious and I don't know how it occurred as all holes had aligned perfectly during assembly prior to the rear spar not aligning. Here's a quote from another post I had done on this issue.

"I ended up remeasuring the HS for twist by comparing plumb lines along the end ribs' tooling holes and determined there was a twist of approx. 15/32 of an inch. I have no idea how or why this occurred as all holes during construction lined up. I went on the assumption that I had somehow introduced the twist while riveting the end ribs, as I had taken the structure out of the cradles and laid it flat to rivet those holes. On that assumption, I drilled out the rivets in the end ribs, then cleco'd the rear spar into place with a cleco in every hole. I then re-riveted the end ribs. After doing that the twist was measured at approx. 7/32. I then riveted the rear spar (my original spar) to the ribs, starting inboard and working outboard, alternating between the left side and right side after each rib. After that the twist was down to about 1/8" and the rivets for the skin to spar lined up perfectly. After riveting the skin to the spar the twist is down to about 1/16 - 3/32, which, I assume, is irrelevant."

Hang in there, I know it's frustrating. Let me know if you have questions about my circumstance.

[Mike H]

Originally Posted by JDBoston

Maybe this is a question for Scott if he sees this: is this a systemic problem with this set of parts in certain kits or builder error? I have tail kit 152 which was shipped with the wings and is still in the crate and I started on the wings first. Is there something that we can do to determine this quickly so we can start the replacement process? I have seen this issue described a few times now from builders with kit numbers earlier and later than mine.

THIS ^^^^

I have the wing and empennage kit as well and will be starting the empennage kit in a few weeks. It would be nice to know if the spar I have will need to be replaced. Can someone post some pictures of the discrepant holes so I can use it as a refernce to determine if I have a problem prior to prepping and priming for final assembly? The one picture that I saw here previously no longer shows up.

[JDBoston]

I think this page desscribes it in detail, looks like the same problem.

http://rv-14a.blogspot.com/2014/05/h...-error-on.html

Would be curious to see what Joe or Scott have to say here.
Need to check my parts to see if this issue occurs, just too involved now in the tanks to look.

[Dennis Harm]

Hi jd and Telford according to joe at vans the computerized boring machine drilling the skin holes has to reposition itself because the rear spar is so long, when doing that it slightly bumped the spar throwing it slightly of alignment. They also don't know which batches this happened. Can't tell if spar is bad until riveting in place. Mine did not set tight when clecoing in place and I should have stopped there but I thought it would pull into the dimples but it didn't,a little work drilling out spar but now it will be right.back to work thanks Dennis.

[AlinNS]

Hi Folks.

Not much too add to that link above, but I did some measuring on the rear spar (HS00903-1). I come up with a discrepancy of .015 between the 26th and 27th hole, then the rest of the holes are all the same. Of course my accuracy likely leaves something to be desired - pretty small numbers! I figure the only way to know, like mentioned above, will be to cleko it together and go from there. Nice to know that Vans is there to help out!

Kit #180

[AlexC]

I also had this issue with a kit received in July 2018 (exact same hole positions that "E" mentioned on his blog here: http://rv-14a.blogspot.com/search/la...l%20Stabilizer). However, after first clecoing the spars and then reclecoing the skins, the problem wasn't as severe, and I just #40 reamed the skin-to-rear spar holes a bit so the rivets would sit straight in the dimples.

Did anyone else with a recent kit (mine is #509) experience this issue?

_Alex

[drtgraves]

Kit 499. No problems

[Bsquared]

Kit 480. Also no problem with any of the skin to spar alignments....empennage kit complete except for fiberglass fit and finish