txaviator

txaviator

Well Known Member
Does anyone have any close-up photos of the horizontal stabilizer? What I am looking for is detail of the rivets. I know this sounds strange, and is not -9 specific (since I am building a -9).

Let me try to explain.....As mentioned in a previous thread, I am paranoid that my rivets look a little too deep. When I glance down the top or bottom skins of the HS, I see uniform little indents around the rivet head itself. Nothing terrible, and not a result of too much air pressure on the rivet gun. Not 'smilies', and not the size of the rivet gun set. As I look at the rivet lines, every single one is uniform in this charecteristic I mention. Almost as if the rivet was set down a little deeper than the dies allowed for, although the dimples were obviously all the same, and I didn't over-beat the c-frame. Instead of seeing a perfectly flat surface with tons of little flush rivet heads, I see a surface where around each rivet head there is a slight indention; as if the dimple dies were just a hair too deep.

It's hard to explain, and may be the exact same on other planes. I have seen tons of unpainted RV's, but all of them prior to beginning my empennage therefore I never thought to look. On the painted ones, maybe the paint takes away some of the effect? It could be the shiny aluminum being dimpled and riveted, playing tricks on my eyes.

I have been through every website I can find, trying to ease my concerns. I have yet to find a close up, kind of angled shot, which will allow me to see other people's riveting. Once I get my new digital, I will try to post photos. Again, it is not real noticeable (and perhaps tough to photograph) but something I would like to put behind me as far as worrying (and I may be worrying about something that is common on EVERY RV)?

Thanks for any help.
 
dimples

I THINK I know what you're talking about because I've noticed it and have looked at lots of other planes to see if I can tell the difference in the dimples.

I have a feeling that your dimples might not be 'crisp' enough. Either that, or you might be hitting them TOO hard. I noticed a difference between my dimples done on the edges of the skins with a pneumatic squeezer and the ones done with a c-frame. I also noticed a difference between my dimples that were done on a table that had some 'flex' in it, and those done on a table that was extremely solid.

I found that the c-frame dimples done on a table without any flex were the best. They were nicely formed and the skin around the dimples was very flat. The dimples I did on the edges with my pneumatic squeezer seemed to cause the edges of the skin to be somewhat 'wavy' and the rivets had the indents around the rivets.

I know this all sounds like black magic, and there are probably other qualities that affect the dimple... like the dimple dies, for instance.

Try experimenting on a scrap piece of aluminum. Put your c-frame on a cement floor and make a couple of dimples. Then put it in the center of a folding table and look at the difference! Try different hammers and hitting both soft and very hard to see what works the best.

-Clay
 
Thanks, Clay

I am certain that my dimpling was done "by the book". I was using a stout table, and didn't use too much force with the hammer/dies. We had a very lengthy discussion on dimpling in my builder class, and I am certain they are correct. Also, I was using brand new dies for the process, and they are lined up perfectly with one another.

I may just be 'seeing things', but a photo from someone else's project would help me to confirm or dispell my paranoia.

Again, it is nothing that looks "bad", it's just that rather than a perfectly flat surface with jillions of little flush rivet heads, it appears every rivet is sunk just a fraction too deep, based on the dimple itself. You "see" dimples rather than a perfectly flat surface. By the way, the rivets along the spar are the same way, so this is also leading me to believe I am just seeing things. Granted, I know that the spar dimples are different since I had to countersink with the cage tool into the spar itself (after dimpling the skin), but they also look the same. Whether I used the pneumatic squeezer or the Sioux 2X rivet gun....all the same. :confused:

Anyone have any close-up photos? Maybe angled, looking from one tip, kind of down the length of the HS? Again, it surely doesn't matter what model of RV...rivets and dimples are rivets and dimples. Any help would be appreciated. Thanks!
 
Get a Technical Counselor

If you have any concerns, now is the time to contact your EAA Technical Counselor. If you haven't made contact with one yet, it's in your best interest to do it. Just get a pair of experienced eyes on your work to confirm that you're probably doing absolutely fine.

)_( Dan
RV-7 N714D
http://www.rvproject.com
 
Gary,

That is simply because you didn't dimple the skin hard enough.

Here is where it wsa dimpled with a normal amount of force and then riveted.

EMPENNAGE%20049.jpg


and here is where the skin was dimpled much harder.
EMPENNAGE%20050.jpg


Notice the slight abrasion around the smoother rivet where it was clearly dimpled harder. That is what I used moving forward to ensure they all came out super flush.

http://jeffsrv-7a.com/EMPENNAGE/03-12-29.htm

Jeff
 
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great photos, jeff

Those photos do a great job illustrating the difference between a 'crisp' dimple and one that isn't so great.

You can hit the dimpler as hard as you want, but if the table has some 'spring' or 'give' in it, you won't ever get a good dimple.
 
Very true. I hit my C-Frame pretty darn hard with my 2lb. dead blow rubber hammer. Dimpling lots of holes and hitting that hard requires hearing protection... Have no mercy on that little C-Frame. Just look for the halo around the hole will tell the story.

Jeff
 
Gary--

I know this isn't the kind of advice you want to hear, but there's a great tool that will solve this problem. Trade your hammer dimpler for a DRDT-2 from Paul Merems. http://experimentalaero.com/DRDT-2.htm

Yeah, I know it's expensive (about $325), but it was my one luxury (no, I don't have a pneu. squeezer like you already do :( ) and I never bought the C-Frame from Cleaveland in the first place, so it really on only cost an extra $150-175. More importantly, it makes perfect dimples EVERY time and does so QUIETLY--plus it's faster since you don't have to keep picking up and putting down your hammer to adjust the skin to the next hole.

That said, I'm sure you'll get the hang of the hammer method like the rest above have suggested pretty soon and you can probably produce equally good dimples with the C-frame given proper technique.

By the way, your video got in the mail on Friday. Please let me know if there is any damage and I'll send your check back to you.

Steve
 
alpinelakespilot2000 said:
(no, I don't have a pneu. squeezer like you already do :( )
Click to expand...


I don't have a DRDT (yet), but I did buy a pneumatic squeezer after I finished my tailcone. You'll appreciate it after you get it. I planned to do my entire RV-10 with the hand squeezer until my tech counselor lent me his pneumatic. You'll go so much faster. It is definitely worth it.

PJ
RV-10 #40032
 
Dimpling isn't a science. And if you WANT to spend more money on a different sort of dimpler, by all means do so. But really you can get beautiful flush rivets by

(a) put skin between dimple dies (either squeezer or in another tool)
(b) Hit it hard enough to get the littler halo completely around it.
(c) Repeat about 12,000 times.

Want to check the quality of your dimple. Stick a flush head rivet in there and feel it with the fingers. If it feels flush, move on.

There's lots of things to spend time and more money on on this project. Dimpling ain't one of 'em.
 
I never did use a hand squeezer. Avery set me up with the pneumatic and that is all I ever used, plus the C-frame. A good sharp crack of the hammer on a C-frame makes good dimples. Use a large plastic mallet like the one Avery sells. The Pneumatic is wonderful along the edges where you have access. I have a 2-1/2" yoke and longeron yoke, plus a 1" and 4" no hole yoke. Get the adjustable set holder. Also pop rivet dimple dies are handy as is the vice grip dimpler.

Have fun,

Roberta :)
 
Thanks for the replies!

I went out and looked at the dimples again, in my HS. I have VERY obvious little 'halo's' and/or the abrasive marks around every single dimple. Therefore, I am almost convinced that I am just "seeing things", based on all of your replies. Jeff's photos were also a big help. Mine looks just like the proper photos that Jeff sent, with the abrasive markings around every dimple.

I am buying a new Canon Digital Rebel tomorrow, and once I get it all dialed in, I will also post some photos. However, I think I am OK. Thanks again for the replies!

BTW, Dan, I appreciate the EAA Tech advice. I have been meaning to do that anyway, and as luck would have it, I went to a local EAA meeting that was scheduled tonight. I joined the chapter, and once all the elderly people got done arguing with each other (literally), the meeting came to a close. Everyone bailed out before I could ask about the local tech counselors, but I will email the President of the chapter and ask him. Wow, talk about some people voicing their opinions! It almost became heated!

Thanks again, everyone.
 
txaviator said:
I joined the chapter, and once all the elderly people got done arguing with each other (literally), the meeting came to a close.
Click to expand...


LMAO!!!!!!!!!! Typical....
 
RV_7A said:
LMAO!!!!!!!!!! Typical....
Click to expand...

Jeff,

I am beginning to think it may be typical? Nothing against these senior members, but my goodness! They went at it like little school kids for the majority of the meeting! Little side discussions, people getting up and leaving the room while making faces of disgust, etc.

Is this typical EAA behavior in many chapters? The only reason I am so concerned, is that I saw NO benefit from this chapter after leaving the meeting, and it was my first one. I honestly thought about getting my check back from the secretary afterwards, but she was in a heated debate with another one of the members over something trivial. I have other chapters I could join, although they are not as close. However, it may be worth the drive to actually have a productive meeting once per month?
 
RV_7A said:
Gary,
That is simply because you didn't dimple the skin hard enough. Here is where it wsa dimpled with a normal amount of force and then riveted. and here is where the skin was dimpled much harder. Notice the slight abrasion around the moother rivet where it was clearly dimpled harder. That is what I used moving forward to ensure they all came out super flush. http://jeffsrv-7a.com/EMPENNAGE/03-12-29.htm Jeff
Click to expand...
Jeff, thanks again for putting those two images up. They PERFECTLY answered the question of 'how hard is enough'. BTW, the rivets on my RV-6 weren't hit hard enough and if you look close you can see (even through the paint). The wing kit and fuse were hard enough. I've learned at fly-ins that most kits look like this :).

B,
 
Idropped out of my EAA chapter recently. There's almost NO talk about homebuilding. Lots of talk about politics, though. As if I needed more of that. With a few exceptions, chapters are mostly social clubs.

What folks should consider is starting a wing of Van's Air Force. Use the White pages here on Doug's site and start forming a regional builders group.
 
Try a different chapter...

Dallas Chapter 168 is full of RV builders and flyers from all over the DFW area. I've been going for a few years now and it is great! We have great presenters at every meeting with plenty of time to talk with several tech counselors who are at every meeting. (including DAR Mel Asberry, this year's winner of the EAA Tony Bingelis award... he's also active on this board)

http://www.eaachapter.com/168

-clay
 
Don't get me wrong guys, the EAA is a wonderful thing. However I never got anything from our local EAA meetings. However thats where I met some of our RV folks.

We formed a small gathering once a month of local RV flyer/builders and we call it the "RV Dinner Gathering" and its a lot of fun, beer, food and lots of RV talk. Life is good now.... :)

RVGROUP.jpg
 
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Look closely... Last time I looked at the map Lockhart was kinda South.... Stay in touch with us man! ;)
 
I looked close, but I don't recognize the resturant. Then again, I haven't been to Lockhart for ages. I think the $100 hamburger book said there was 5-star BBQ place there, but it didn't make much sense to fly-in from San Marcos when I had my Cherokee.

Maybe I'll try to make Razoos at the end of the month.

Thanks,
Tracy.
 
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