[alpinelakespilot2000]

A question for anyone well-versed in "acceptable" building practices...

I recently drilled out a rivet that had folded over significant enough that it really elongated the hole in the rib. I am, at this point, experienced enough to know that I am not going to be able to get another rivet in there without it folding over when I squeeze or buck it. Even going up to a larger rivet (from 3/32 to 1/8) or pre-squeezing a rivet might not solve the problem entirely. I'm not sure that I want to take that risk without considering all my other potential options.

Yes, I recognize that many poorly set rivets should (according to Van's as well) just be left alone, given that more damage can be done drilling it out than leaving it as is. However, this was not possible in my case. I slipped with the gun and really mangled both the head and the tail. (Don't ask me how! )

Is it permissible to add a "third" layer (e.g. a small dimpled 0.5" square piece of aluminum) beneath the rib flange so that I could rivet through the skin, rib, and that extra layer, with the extra layer serving to provide support to the rivet shank while I squeeze it? It seems like a reasonable way to solve this problem, but any comments on whether it is acceptable or not would be appreciated. I'm just trying to slow down and consider all my options before I completely ruin an otherwise very good part.

Thanks,

Steve

 

[Hawkeye7A]

"cheater rivets"

Steve,
I (and I suspect many others) did just what you are thinking of doing; i.e. adding a small piece of aluminum to add some integrity to the shop head end of the rivet. It'll work and won't hurt anything but Van's has what they call "cheater" or "oops" rivets that have the same head as a standard AN426AD3- but the shank of the AN426AD4-. They sell them in 4 different lengths and they work great for hiding the occasional boo-boo. This is all, of course, assuming your enlarged hole hasn't been enlarged too much. Early in my empennage before I learned about these alternate rivets I plugged an oversized hole with a standard 1/8" rivet. Hopefully when it's painted it won't stand out like it does now! Hope this helps.

hawk
RV-7A fuse
N728E (reserved)

 

[alpinelakespilot2000]

Thanks Hawkeye--

I do know, and have used--I must admit--a couple oops rivets to date, though I try not to use them except as a last resort. My problem in this case is that I also slightly enlarged the skin hole. I'm not sure a standard 3/32 flush head, whether on a 3/32 or 1/8 shank, will be big enough on the skin side. I will probably go up to a full size 1/8 flush rivet because I need the larger head on the now larger skin hole.

Fortunately, my mistake is in a location where I can get my squeezer into, which means I can redimple it for a 1/8 rivet. I've done some experiments and found that my dimple dies when squeezed will produce very nice dimples even while dimpling two layers at a time.

Actually, I too (but accidently) used a standard 1/8 flush rivet on my empennage (VS) when I mistook it for one of the oops rivets. Surprisingly, even without re-dimlpling it got pretty flush, though it did distort the skin slightly. Nothing paint won't hide I think, which is probably what you're facing as well. It's certainly strong enough!!!

Again, thanks for the input. Hoping a few more will confirm the feasibilty/acceptability of this route.

Steve

 

[Rick6a]

I recognize that many poorly set rivets should (according to Van's as well) just be left alone, given that more damage can be done drilling it out than leaving it as is. Is it permissible to add a "third" layer (e.g. a small dimpled 0.5" square piece of aluminum) beneath the rib flange so that I could rivet through the skin, rib, and that extra layer, with the extra layer serving to provide support to the rivet shank while I squeeze it? It seems like a reasonable way to solve this problem, but any comments on whether it is acceptable or not would be appreciated.
Steve

I could tell you what I as a production worker would do based upon years of anticipating how the engineering department at McDonnell-Douglas would "disposition" such a typical "nonconformance." Take heart, yours is not an uncommon squawk. They would tend to overengineer the fix and so would I. Fabricate a strip of .032 aluminum stock centering on the subject hole of a dimension long enough to maintain e.d. along the rib flange while picking up two adjacent rivets on either side of defect hole. Round the corners, break all sharp edges, radius the repair stock so no chaffing can exist between the repair stock and the radius of the subject rib flange and web. Alodine, and install repair stock to underside of rib flange (they would have you fay seal and bond the repair strip on with proseal) to pick up all five holes brought up to 1/8" and install NAS1097AD4 rivets.

Rick Galati RV-6A "Darla"

 

[alpinelakespilot2000]

NOTE: THE POST BELOW INDICATES THE USE OF A 1/4" RIVET. IT IS MEANT TO SAY 1/8" RIVETS. NEEDLESS TO SAY, THIS CHANGES THE DYNAMICS OF THE DISCUSSION!!! SEE LATEST POST FOR RESOLUTION.

Thanks Rick--it's great to get a "disposition" from someone in the business! Your idea definitely seems to be the ideal. Let me elaborate on my problem and see what you think...

The offending rivet is (of all places, ) the TOP forward-most rivet on my right leading edge, on the second-outboard-most LE rib. Thus, the problem with using your 2-before/2-after backing splice is that I don't have any holes ahead of my offending hole. Additionally, again, I think I will need to use a regular 1/4" flush rivet because I'll need the full head size to cover up the enlargement I've already made to the skin--it's more enlargement than normal.
(I can reach the two forward-most holes on that rib with a squeezer--to re-dimple for a 1/4" rivet--because I have already cut out the leading edge landing light hole.) Rivets #3 and aft, however, I will not be able to redimple or dimple to the next larger size, so I would have to use the NAS rivets here.
In short, this is why I was originally thinking a 1-hole backing strip.. perhaps affixed with proseal or epoxy just to support the flush 1/4" rivet until it begins to set might be sufficient.

Since I can't do exactly what you recommend, how does this new info. change any suggestions you would offer. My primary concern is, as always, structural integrity. That said, since it is the top leading edge of the wing, cosmeticly appealing suggestions would, all else equal, win out. I have no problem with one or two (or more) 1/4" flush rivets here if I can redimple them sufficiently to get a flush fit.

Any additional thoughts you (or others) have here would be greatly appreciated. Thanks again.

Steve

 

[Rick6a]

Thanks Rick--it's great to get a "disposition" from someone in the business! Your idea definitely seems to be the ideal. Let me elaborate on my problem and see what you think...

The offending rivet is (of all places, ) the TOP forward-most rivet on my right leading edge, on the second-outboard-most LE rib. Thus, the problem with using your 2-before/2-after backing splice is that I don't have any holes ahead of my offending hole. Additionally, again, I think I will need to use a regular 1/4" flush rivet because I'll need the full head size to cover up the enlargement I've already made to the skin--it's more enlargement than normal.
(I can reach the two forward-most holes on that rib with a squeezer--to re-dimple for a 1/4" rivet--because I have already cut out the leading edge landing light hole.) Rivets #3 and aft, however, I will not be able to redimple or dimple to the next larger size, so I would have to use the NAS rivets here.
In short, this is why I was originally thinking a 1-hole backing strip.. perhaps affixed with proseal or epoxy just to support the flush 1/4" rivet until it begins to set might be sufficient.

Since I can't do exactly what you recommend, how does this new info. change any suggestions you would offer. My primary concern is, as always, structural integrity. That said, since it is the top leading edge of the wing, cosmeticly appealing suggestions would, all else equal, win out. I have no problem with one or two (or more) 1/4" flush rivets here if I can redimple them sufficiently to get a flush fit.

Any additional thoughts you (or others) have here would be greatly appreciated. Thanks again.

Steve

Wow.. Your additional details certainly complicate things a bit. Complicated...but possibly workable. First off, are you sure the offending hole is so large as to require a 1/4" rivet? That takes a .250 hole and is relatively large. In addition, do you even have a 1/4" dimple die? The largest dimple die I have has a .164 pilot. This is normally used for a 5/32 screw. In your case, machine countersinking is out of the question. Even setting such a large solid rivet would be a challenge. I'd still be inclined to fabricate a repair strip as outlined before only pick up two or even three holes directly aft of the defect hole, again bringing them up to 1/8" to accept NAS1097AD4's, then (hopefully) clean up and dimple the defect hole in the skin and the repair stock to accept a 5/32 SCREW. You are going to have to get creative in figuring out how to affix a nut and washer over the (opposite) dimpled surface of the repair stock. Perhaps a large washer/spacer installed first around the dimple would work. Then fabricate a suitable washer with a .165 hole to stack on top of this for the screw nut to rest upon. In the end, a screw installed through the skin at this location would be more than acceptable from a cosmetic point of view. Make no mistake though. I'm no engineer and don't pretend to be. In the work world I came from, the engineering guys would have no problem in writing a disposition directing the shop to scrap and replace the skin!

Rick

 

[alpinelakespilot2000]

Aren't 1/8 and 1/4 the same size?

Oops. Now I feel stupid! I did mean 1/8 and not 1/4. Sorry for wasting your time, Rick! Thankfully, the scenario you laid out based on my false info. was not necessary! Man--I can just imagin having a 1/4" bolt in the leading edge of my RV. That would be one unique -9!

Actually, as with many of my "issues," things that appear so awful turn out to be non-issues. I just resolved my crisis. I drilled out the offending 3/32 rivet. Drilled up to 1/8", re-dimpled with 1/8 dimple dies, and used a AN426AD4-4. My newly re-dimpled rib flange, even though slightly enlarged, looked like it would support the rivet shank by it self, and it did, more than adequately to be squeezed. I do have a nice 1/8" flush rivet on my leading edge that probably just cost me my Oshkosh Grand Champion Award which I almost certainly would have won , but the crisis was averted. The info. in your first post, Rick, is definitely something to go into my "will-probably-be-needed-in-the-future" file. I wouldn't wish on my worst enemy the need to follow the suggestions of your second post.

Thanks again for the help.

Steve

 

[Ted Farmin]

Riveting enlarged holes

Keep in mind that a hole of this nature can be repaired with a 4-40, 6-32, screw with lock nut and epoxy fill the head, sand and prime to hide.
Remember we are expiremental of which is so Wonderful.
Also you mentioned a high rivet, put scotch tape on two sides and file the head down until you start to tear the tape and polish out with 320 paper.
Ted

 

[txaviator]

Steve...

Steve wrote: "Man--I can just imagin having a 1/4" bolt in the leading edge of my RV. That would be one unique -9!"

My response (all in fun, of course) is that I just can't imagine having a nosewheel of the leading end of an RV-9!

 

[alpinelakespilot2000]

Steve wrote: "Man--I can just imagin having a 1/4" bolt in the leading edge of my RV. That would be one unique -9!"

My response (all in fun, of course) is that I just can't imagine having a nosewheel of the leading end of an RV-9!

Be careful, Gary! If I do end up ordering a 9a fuse. I'm also going to call Van's and have the following conversation:

Me: "Hi, this is Gary, my builder number is 91140. I know I ordered that -9 fuselage, but I REALLY REALLY want a 9A. Can I please change to a 9A?

Van's: "Hi Gary. We'd be happy to accomodate your change of plans. We find that most people prefer the 9 with the little wheelie thing on the front."

Me: "Do you think a nosewheel will look OK here in Texas?"

Van's: "Yes, absolutely, especially in Texas. Granted, every kit we sell in Texas has the wheelie thing in the back, because that's where real men live, but hey, someone's got to be the first wimp in Texas to buy one."

[Unheard Van's employees whispering in the background: "this guy's going to get pounded!"]

Van's: "Don't worry, your 9A kit is on its way."


Now, when you're opening your fuse. kit from Van's in a few months, remember mocking me while you sweat over what Van's actually sent you!

Have a good fourth of July--time to go do some camping and fishing for me!

 

[Hawkeye7A]

-9 or -9A; show or go?

Steve,
Glad to hear you solved your problem. You also mentioned making the choice between Tri-gear or tailwheel. What made the decision for me was simply a matter of initial insurance costs. Being a "0" time taildragger when I got my first plane ('59 C172, still have it) the insurance at that time was $984 without yet having soloed and only 13 total hours in my logbook. I looked at a C140 while shopping back then and the same coverage on that would've been $2800! Fairly easy choice for me. Hence, my -7 is going to be an "A". As far as your leading edge fix, you also have to make the decision to build a Grand Champion or a plane you'll be equally proud of to just fly the wheelpants off! Happy bucking!

--hawk

 

[alpinelakespilot2000]

Likewise, thanks, Hawk. Like you, I vowed from the start to build a "flyer" not a "show" plane, so a larger flush rivet doesn't bother me in the least. It's even stronger than what I would have had there originally.

Insurance is part of the equation on the 9/9a. I'm tentatively planning liability/comprehensive only, so the tailwheel would not likely affect my insurance as much, but probably still a little. The big thing I've discovered since I moved to this part of Washington is how gusty and windy the spring and summer can be. I live on the leeward side of the Cascade Mountains. The wind comes down off them with pretty good consistency and stregth. The typical day's wind in the summer might be 15-30 mph with significant gusts as well. I'm sure many tailwheel pilots could handle this, but I don't have significant tailwheel time and I want to be able to fly any day I want, regardless of what the winds are doing. (The one nice thing about where I live is that almost every day of the year is a VFR day, with perhaps one month in the winter).

Thanks again for your help. Happy fourth.

Steve