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Horizontal Stabilizer - Rear Spar Hole Misalignment

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Ran into an issue while trying to finish up the horizontal stabilizer. Everything thus far has fit like a glove, until now. Page 08-12, step 3 has you to insert the rear spar into the stabilizer, cleco it to the backs of the inspar ribs, and then rivet it to the ribs. Step 4 then has you to rivet the skin to the rear spar flanges.

Most of the holes line up fine and can accept the -3 flush rivets with no problem. However, for some reason, on both top and bottom, and at opposite ends, the holes get off alignment somewhat for a series of about 20 or so holes in a row. It wont help to take out the clecos and slide the spar down a bit, since the misaligned holes at one end are in the opposite direction as the other end. In other words, correcting the alignment at one end will only make the other end worse. The plans never had you final drill these holes at any point. Pictured is my worst case misaligned hole.

I may be able to force the rivets in, but worry they will be angled excessively to one side.

Of course my other option is to final drill the holes with an #40 reamer which I do have. Bad part about that is the holes in the spar would no longer be perfectly round.

Has anybody else run into this? Am I splitting hairs here?

Any suggestions are very much appreciated
 
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A friend just told me that a builder he knows in CO. had the same problem and if I understood correctly Vans sent him some new parts. Suggest contacting them, it was said that some holes were punched incorrect?

FWIW, Larry
 
Thank you for the reply Larry. When he came across a hole misalignment issue, was it on these same two parts, the horz stabilizer rear spar and skin for an RV14?

Mispunched parts are a possibility, and I will contact Vans. However, they are so close, I am inclined to believe either I have something ever so slightly off position in the assembly process, or else its a tolerance stack up of some kind. This kit is incredibly precise, but no matter what, it cannot be dead on perfect everywhere. Other than this, this stabilizer assembly appears to be extremely straight and true.

I am really curious whether or not these holes aligned perfectly for other RV14 empennage builders.

Thanks!
Chuck
 
Path forward

Okay, after starring at my stabilizer this morning for a bit, I figured out what happened. With the stabilizer mounted in its jig with the leading edge downward, and then when sighting across the length of the trailing edge of the skins, there is an ever-so-slight dip in the middle of the stabilizer, probably on the order of 1/16 inch. I think had the plans had you to cleco in the rear spar prior to riveting the front spar, stringers, and inspar ribs, this would have been avoided. Of course it would have to be removed before actual riveting so you can get the bucking bar inside the stabilizer, but at least everything should be perfectly straight. Taking out this dip would require removing a minimum of 242 skin rivets. Not happening. Perhaps I should have known to cleco in the rear spar anyways. Oh well, chalk it up as a lesson learned. I'll know next time!

With that being said, I don't feel this mistake will be a showstopper. I will contact Vans on Monday to get their opinion. But I think this will be fine by sliding the rear spar a bit to split the error, and then ream the holes in the spar that still don't line up perfectly. I think I can line them up such that only very slight reaming will be required, not compromising the hole shape excessively.
Chuck
 
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HiPlanesDrifter,
See the following links to determine if you have a similar issue:

Description of problem with images
http://rv-14a.blogspot.com/2014/03/empennage-horizontal-stabilizer-factory.html
Resolution of problem
http://rv-14a.blogspot.com/2014/05/horizontal-stabilizer-factory-error-on.html
His original horz. stab. assembled well until the rear spar was added. Clecos were installed from all possible directions and a misalignment manifested itself every time about half way along the left and/or right sides, top and/or bottom of the assembled horz. stab. The hole spacing on the rear spar was off in his opinion and I would have to agree. However, the solution required more than just a replacement spar. Feel free to contact him through his blog. Second try was built without issue.
 
Chuck

Call Vans on Monday and ask for me. This sounds like a previous problem that we encountered. We'll get you fixed up...
 
Yes, looks like same issue

abrandt,
Thank you for the tip off. I looked at the issue as seen on the links you provided, and it appears I have the same problem.

Joe,
Thank you as well for your reply. I will call you Monday morning. It looks like I have something going on with my rear spar much like in the links that abrandt supplied to me. Even at the exact same rivet holes. I will put down the horizontal stab and instead start the elevator now.

This is precisely one of the main reasons I chose to build an RV over other kits. With so very many helpful folks, along with a very customer oriented Vans staff, I knew I would never feel alone or out there on my own.
Thanks all!
Chuck
 
Same issue - HS rear spar hole misalignment

Hi Chuck,

I believe I have the same issue with the HS rear spar. I just got off the phone with Van's support and the gentleman I spoke with is going to get back to me after speaking with another Van's employee who is more familiar with this issue. I was wondering what all was entailed for you in getting the rear spar to fit?
 
This is why I gladly pay my dues!

Yikes! I'm just about to assemble the rear HS spar to the skins and happened across this thread tonight. I think a few minutes with the caliper before I do would be well spent. If my rear spar has this issue I'd rather know now. Thanks to everyone for the trouble shooting on my behalf!
 
Hor. Stab. Rea spar

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.
 
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.
 
Have you checked for twist in the HS?

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.
 
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.
 
Rear spar rv14

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.
 
Did some measuring

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
 
same alignment issue with rear spar (July 2018)

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/label/08 Horizontal Stabilizer). 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
 
Kit 480. Also no problem with any of the skin to spar alignments....empennage kit complete except for fiberglass fit and finish
 
No problems with #433 either. Everything fit like a glove on my HS.

However, while machine countersinking the rear spar I managed to mangle one hole due to chatter. I drilled it out to a #30 size and used a NAS1097 "oops" rivet. You'd be hard pressed to find it from the skin side as it looks just like an AD3 rivet. From the shop head side it's obvious.
 
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Thanks gentlemen ... I appreciate all the responses, and glad you did not have any issues with the alignment!

_Alex
 
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