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  #1  
Old 06-10-2017, 01:35 PM
LettersFromFlyoverCountry's Avatar
LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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Location: St. Paul, MN.
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Default Confused by Section 13 Step 5

I'm confused by Section 13, step 5 of the RV-12 instructions. First, of all, as shipped from the factory, why aren't both spars mirrors of each other? The pre-riveted rib doublers aren't the same for both.

And as the schematic shows on this step, you're working on the forward side of one and the aft side of another.



This step tells you to rivet remaining open holes in the indicated doublers, basically three rivets on each flange.



But, at least on the underside of the farthest left doubler with open holes, doing so interferes with any rivet that would go in the opposite side doubler.



Maybe this isn't a problem in most of the doublers, but it is for the one farthest outboard (of the ones we're talking about in this step). The pulled rivet for the doubler in this step, will eventually interfere with trying to put a rivet in the flange holes for the doubler that's on the other side.


Or, if one rivet is to tie the two doublers together (and I'm positive that that's not the case), you would have to have a spacer on the back side AND a much longer rivet.
As you move inboard, there sees to be a bigger gap between the spar web and the doubler flange

Very weird
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RV-12 project status: Waiting for the RV-12iS fuselage subkit
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Last edited by LettersFromFlyoverCountry : 06-10-2017 at 01:39 PM.
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  #2  
Old 06-10-2017, 02:11 PM
DHeal DHeal is offline
 
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The spars are not "mirror-images" of each other because one spar sits further forward on the wing chord than the other -- remember that the spars overlap through the center-section. So there are different pieces required to properly establish the proper relationships of all ribs, etc.
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  #3  
Old 06-10-2017, 03:42 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by LettersFromFlyoverCountry View Post
Maybe this isn't a problem in most of the doublers, but it is for the one farthest outboard (of the ones we're talking about in this step). The pulled rivet for the doubler in this step, will eventually interfere with trying to put a rivet in the flange holes for the doubler that's on the other side.


Or, if one rivet is to tie the two doublers together (and I'm positive that that's not the case), you would have to have a spacer on the back side AND a much longer rivet.
As you move inboard, there sees to be a bigger gap between the spar web and the doubler flange

Very weird
The holes in the angle are over sized to allow the rivet to be inserted from the opposite side of the spar and not interfere with the angle. The rivets attach the rib to the spar web only.

Not trying to be snarky, but may I suggest that every time the notion comes to mind that something doesn't make sense or isn't working out like you would expect, that you just read ahead and see what is going to happen in that area later.

I would estimate that at least 700 pairs of wings have been built from the same parts you are working with, so if something doesn't seem right, the highest probability is that you just don't yet see the full picture.

David explained why the spars are different.... when the wings are mounted to the airplane, the spars are not aligned. One spar will be further fwd than the other, so the wings can not be built as mirror images of each other.
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  #4  
Old 06-10-2017, 04:10 PM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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Yes. Of course I can read ahead. But the plans are 8 miles away.

I'm not doubting anything about the design. I was just asking questions.
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  #5  
Old 06-10-2017, 05:05 PM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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OK, so I even though I'd already had my Saturday Happy Hour beer, I drove back out to the hangar, checked the plans and figured out what you were saying. At least what I think you were saying.

What I think you were saying is:

"Those holes you think are rivet holes in the doublers angle on the other side of the spar from the angle you're riveting, may look like rivet holes but they are not. They're only there so the rivets you're inserting can be fully inserted."

Recreation AND education.
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RV-12 project status: Waiting for the RV-12iS fuselage subkit
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Last edited by LettersFromFlyoverCountry : 06-10-2017 at 05:37 PM.
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  #6  
Old 06-11-2017, 04:08 AM
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mike newall mike newall is offline
 
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Bob,

You are from the Colonies and speak the language....

We have to read the instructions, translate into British and then move forward.... And we have built 2 RV's before !

Provided you understand that the plans and instructions are written by Enjuneers, who mainly take great delight in dealing with the minute and interesting detail - sometimes with irony, which is unusual, the RV12, 14 and 10 plans are way, way better than previous.

You are right to question, this forum is a superb resource and Scott's input is absolute pure gold. Sometimes, however, it takes a few reads to understand and the temptation to move forward using assumed wisdom is tempting.

A question - how many nutplates have you drilled out because you thought you could fit them but later found they went through layers of structure.....?

Just saying, because I have a special drill just for that in our shop
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  #7  
Old 06-11-2017, 04:30 AM
BigJohn BigJohn is offline
 
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Bob,

Your post brings back memories from 2010 or so when I was building my wings. I remember going through the same thought processes at the time- somewhere between "these plans must be wrong" and "I must be missing something". Of course the latter proved to be true, as it does at least 99.99 percent of the time. Finaly occurred to me that the two wings are not mirror images. A "duh" moment, but always good to humbled now and then!

On another topic, early on in the build I adopted the practice of running down to PostNet and getting a copy made of the plans for each sub-kit when it arrived. One for the house and one for the shop. Saves those extra trips after the evening refreshments!

Very glad to hear you are staying in the RV community with 12. Build on!

John
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Last edited by BigJohn : 06-11-2017 at 09:10 AM. Reason: Typo
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  #8  
Old 06-11-2017, 07:27 AM
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XOverZero XOverZero is offline
 
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Default Get the plans

Bob, I recommend getting the plans on CD-ROM from Van's. You can load them onto a laptop and have them available whenever and wherever. The big added bonus with that is having ALL the plans. You can read ahead in sub-kits you haven't ordered yet. Even though those plans will not be fully up to date, they are 90-something percent.

It's akin to turning on the lights instead of fumbling in the dark. Or, with a nod to our brethren from the home isles, "Bloody Brilliant."

Cheerio, then.
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  #9  
Old 06-11-2017, 12:08 PM
greghughespdx greghughespdx is offline
 
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Quote:
Originally Posted by XOverZero View Post
Bob, I recommend getting the plans on CD-ROM from Van's. You can load them onto a laptop and have them available whenever and wherever.
For my project and the one I'm involved in, I've actually taken the -12 and -8 plans from CD and loaded them (with access limited to me only of course, not shared publicly) on Dropbox, where I can view them anywhere there's Internet, at any time and from any device. I have often used my phone or tablet or someone else's computer to pull them up so I could refer to them.
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  #10  
Old 06-11-2017, 04:25 PM
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LettersFromFlyoverCountry LettersFromFlyoverCountry is offline
 
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Default

I'll probably just scan 'em so I can gave a set at home.

FTR, I never thought the plans were wrong. I just like to know why things work.

It's probably an OCD thing.
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RV-12 project status: Waiting for the RV-12iS fuselage subkit
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