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  #11  
Old 09-26-2022, 07:33 PM
llohrman2 llohrman2 is offline
 
Join Date: Dec 2018
Location: Wichita
Posts: 16
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You'll have to check out our RVator Builders Group here in Wichita. We meet the 3rd Saturday of every month. Look for meeting notices on Facebook-
AirCapital RVators
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  #12  
Old 09-26-2022, 07:44 PM
wirejock's Avatar
wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
Posts: 5,690
Default #4

Quote:
Originally Posted by wirejock View Post
Honestly, if Vans said to do it a certain way, I print the e-mail, file it and go. Why question it?
Disregard this post.
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Larry Larson
Estes Park, CO
E-mail: wirejock at yahoo dot com
Builder Blog: http://wirejockrv7a.blogspot.com
Donated 12/01/2021, plus a little extra.
RV-7A #73391, N511RV reserved
Disclaimer
I cannot be, nor will I be, held responsible if you try to do the same things I do and it does not work and/or causes you loss, injury, or even death in the process.
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  #13  
Old 09-27-2022, 10:10 AM
Desert Rat Desert Rat is offline
 
Join Date: Aug 2018
Location: Wichita KS
Posts: 1,048
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Larry- No need to disregard anything. I welcome opinions. I just needed to talk through it.
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Terry Shortt
AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
#72651
https://eaabuilderslog.org/?blprojec...t=all&listcat=
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  #14  
Old 09-27-2022, 10:47 AM
CATPart CATPart is offline
 
Join Date: Jan 2012
Location: up up and away
Posts: 380
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Quote:
Originally Posted by Desert Rat View Post
If you make the fuselage bracket longer, even by a little bit, it's creating more of a bending moment into the fuselage structure. I realize it's not much, but it's something.
To answer this concern, some images of the structural arrangement here would be helpful. Would be good to see both the mounting bracket and its backup structure. Actual pics or snippets of the drawing. I doubt it is a problem, but lets see to be sure.
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  #15  
Old 09-27-2022, 11:12 AM
RV7A Flyer's Avatar
RV7A Flyer RV7A Flyer is offline
 
Join Date: Jul 2013
Location: US
Posts: 2,827
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If you reorient the nutplate and drill another hole, what will the edge distance be to the existing hole (once the new one is drilled or reamed to final size for the bolt)? Looks awfully close to me...

I'd go with #4. Easiest and cleanest solution, IMO. Not to mention, it's what the Van's engineers recommended.
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  #16  
Old 09-27-2022, 01:21 PM
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PaulvS PaulvS is offline
 
Join Date: Aug 2019
Location: Western Australia
Posts: 1,275
Default Option #5

This may be another option to consider: Rivet the plate nut to a round .025 doubler and then rivet the doubler to the bracket using the errant hole and another new hole on the other side. Clock the holes as required.
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Building RV-6A #22320 O-320 FP. Wings and tail complete, fuselage almost done, working on canopy.
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Last edited by PaulvS : 09-27-2022 at 01:23 PM.
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  #17  
Old 09-27-2022, 02:25 PM
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RV7A Flyer RV7A Flyer is offline
 
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Location: US
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I dunno, whenever I ask [a lawyer/a surgeon/a tax professional/Van's aeronautical engineers/any expert] what I should do, the very next thing I do is NOT do that, go to the internet, and get every opinion under the sun until I find one that I like because it's [easy/cheap/looks about right], and then I do that.

After all, they're just "so-called 'experts'", right? What do they know?
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  #18  
Old 09-27-2022, 02:50 PM
Desert Rat Desert Rat is offline
 
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Hey guys-

After sleeping on it, I've decided to go with van's suggestion. Builder support confirmed with me this morning that an additional small (around .25" ) lever arm of extending the ears and notch on a new steel bracket outboard to match the existing erroneous pilot hole is not a factor worth considering.

As far as "easiest" The easiest and cheapest solution by far would have been to just drill out 1 ear of the nutplate to #30, use the existing hole to mount it and move the whole nutplate inboard by that amount. unfortunately, I couldn't get past the idea that I was unsure of the loads carried thru that area and vans felt the better option was to extend the steel bracket a bit.

Discovered that there's now a metal supermarket here in Wichita, so I called them up and am having them cut an oversized blank with a nice bend for the flange that I can final size here at home. Should be ready in a couple of days and we can put this one to bed.

For those that asked for pictures, I guess that I thought what's on the RV7 was a typical enough arrangement that everybody would know what I was talking about, but I'll try to explain;

I've already pulled the bracket off the offending side, but here's a couple of pictures of the other side to show how it goes together.

The steel bracket, primer yellow in the photo, is held on the fuselage via 2 AN3 bolts thru the skin into a beefy angle associated with one of the vertical members in the footwell area. The aluminum tab coming off the tank is fabricated from 1/8" angle that rivets thru the root rib nose into a stiffener plate inside the tank.

The tank side tab gets a nutplate on the front side for a AN4 bolt and the bolt goes in from the back thru the slot. It takes a big washer and only gets lightly snugged down, not torqued.

The idea is that it fully supports the inboard nose of the tank in the vertical vector, but if you hit something and bend the wing back, the tank side (bolt) can slide out of the groove on the fuselage side without tearing the end rib out of the tank, thus spewing fuel everywhere.

It's a clever design, but you can see how it gets complicated fast if everything isn't where it's supposed to be.

Thanks for all the input. It's always a pleasure to work through stuff like this with you guys.
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AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
#72651
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  #19  
Old 09-27-2022, 03:13 PM
Desert Rat Desert Rat is offline
 
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Quote:
Originally Posted by RV7A Flyer View Post
I dunno, whenever I ask [a lawyer/a surgeon/a tax professional/Van's aeronautical engineers/any expert] what I should do, the very next thing I do is NOT do that, go to the internet, and get every opinion under the sun until I find one that I like because it's [easy/cheap/looks about right], and then I do that.

After all, they're just "so-called 'experts'", right? What do they know?
pump the brakes there for a minute. I get your frustration at seeing what you describe, but this is not that.

1st of all, the Van's tech support guys are great at what they do, but it's not like they have some magical power to always be right with off the cuff answers. It seems likely that while they are going to give you a solution that they know will work, it doesn't guarantee that it's the only solution or even the best one. Just that it's one they have in their toolbox that they can hand to you efficiently and promptly.

As far as the Aeronautical Engineers- I have no doubt that tech support could have kicked this upstairs to engineering who could have then spent a week modeling this and figuring out if I could move one nutplate by 1/8" Is it reasonable to ask them to do that? Of course not.

They are devoting resources to my question as appropriate to the significance of the deviation. I'm good with that. I've explored other options and have elected to go with their suggestion because as I have previously said, there's obviously a lot going on in this little corner of the airplane and I don't see another solution that GUARANTEES the same design margins.

This isn't because any of them are obviously bad suggestions, but rather because I lack the resources to verify design margins at my home garage/airplane factory.

As far as the rest of your comment. I'm not offended by what you said, and welcome your input. I've seen the same uncomfortable tendency for people to sometimes keep asking until they get an answer they like from somebody who may or may not be qualified to give it. But, I've been in the aerospace business in one way or the other for over 30 years now and want to make it crystal clear that I'm not one to take the easy way out over the right way. Hence my lengthy reply.
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Terry Shortt
AGI, CFI, CFII, MEI, A&P, Janitor
RV7 Empennage & Wing done
Fuselage almost done
Avionics almost done
90% done, 90% to go
#72651
https://eaabuilderslog.org/?blprojec...t=all&listcat=

Last edited by Desert Rat : 09-27-2022 at 03:19 PM.
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  #20  
Old 09-27-2022, 04:36 PM
RV7A Flyer's Avatar
RV7A Flyer RV7A Flyer is offline
 
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Location: US
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Quote:
Originally Posted by Desert Rat View Post
pump the brakes there for a minute. I get your frustration at seeing what you describe, but this is not that.

1st of all, the Van's tech support guys are great at what they do, but it's not like they have some magical power to always be right with off the cuff answers. It seems likely that while they are going to give you a solution that they know will work, it doesn't guarantee that it's the only solution or even the best one. Just that it's one they have in their toolbox that they can hand to you efficiently and promptly.

As far as the Aeronautical Engineers- I have no doubt that tech support could have kicked this upstairs to engineering who could have then spent a week modeling this and figuring out if I could move one nutplate by 1/8" Is it reasonable to ask them to do that? Of course not.

They are devoting resources to my question as appropriate to the significance of the deviation. I'm good with that. I've explored other options and have elected to go with their suggestion because as I have previously said, there's obviously a lot going on in this little corner of the airplane and I don't see another solution that GUARANTEES the same design margins.

This isn't because any of them are obviously bad suggestions, but rather because I lack the resources to verify design margins at my home garage/airplane factory.

As far as the rest of your comment. I'm not offended by what you said, and welcome your input. I've seen the same uncomfortable tendency for people to sometimes keep asking until they get an answer they like from somebody who may or may not be qualified to give it. But, I've been in the aerospace business in one way or the other for over 30 years now and want to make it crystal clear that I'm not one to take the easy way out over the right way. Hence my lengthy reply.
I appreciate your response, and I didn't mean to imply that you, personally, were avoiding adopting the solution provided by Van's and purposefully looking for an alternative for any reason, only that I've seen it over and over and over here and elsewhere. And thanks for the pleasant response, I realize what I wrote could seem harsh; I just don't want to see anyone "blow off" answers they don't like, implement a (worse) solution because they like it and TLAR, and end up in a world of hurt when things go bad.

Like you, I've been in aerospace for over 30 years now, so I tend to be *very* conservative in solutions, analysis, etc. Glad you're of the right mind, to do the jobs right, and not just the easiest or cheapest way!

Best of luck as you proceed...let us know how it turns out!
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