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  #1  
Old 01-01-2019, 06:26 PM
Draker's Avatar
Draker Draker is offline
 
Join Date: Jun 2016
Location: Livermore, CA
Posts: 217
Default Aft canopy deck position along the longerons

Happy new year everyone. Wish I could share in the happiness, but I just found what's possibly a catastrophic mistake I made on the RV, and wanted to share it. Obviously this is going to involve a long discussion with Van's, but I thought I'd start a discussion here to potentially prepare myself for the extremely bad news I have coming.

Long story short, it looks like I built the whole forward and mid fuselage around incorrectly bent and drilled longerons.

I'm at the point in the build where I'm disassembling the forward fuselage to prep the surfaces, dimple, and countersink them for riveting. While countersinking the longerons, something just didn't look right. The top holes I had drilled for the aft canopy deck were way too far aft. So I clecoed the longeron back to the mid-fuselage, and pulled out the F-721B aft canopy deck pieces. Lo and behold, the holes are indeed way too far back:



It looks like way back when I drilled the canopy deck to the longerons, I had the forward edge of it in the wrong position:





How I made the mistake: The distance between "Beginning of Curve" and "End of Curve" is 30 27/32" which is almost exactly the length of the F-721B canopy deck piece, so I ASSumed that it was to be positioned between these marks.

So at the very least, I'm going to be ordering two more longerons, re-bending them both, and re-drilling them to the skins. As a side note, the holes in the longeron-facing aft fuselage skins are already dimpled so it's not going to be fun to re-drill those. But that's the least of my problems.

Unfortunately, as a result of incorrectly locating the canopy deck pieces, my longerons must have been bent in such a way that they align with the incorrect placement. As proof, when I lay the canopy deck piece against the longeron in the correct position, it does not match up with the curve of the longeron:



This means I have built the entire forward fuselage around incorrectly bent longerons. This may mean that I'm scrapping a fair bit of the front fuselage, too, likely at least the side skins.

To say I'm disappointed is an understatement. Please help me brace for the bad news from Van's. I'll be calling them pretty much as soon as they re-open from the holidays. And future builders, please learn from my carelessness.
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Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 1/2/2019
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  #2  
Old 01-01-2019, 06:40 PM
Kyle Boatright Kyle Boatright is offline
 
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Location: Atlanta, GA
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Can you not "simply" replace the longerons? Most everything else is already match hole punched and should fit right back together.
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  #3  
Old 01-01-2019, 06:50 PM
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wirejock wirejock is offline
 
Join Date: Oct 2005
Location: Estes Park, CO
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Default Longerons

Agree. Everything else is prepunched. You may find the right size and type of angle at a local metal distributor. Check with Vans but I think it's 6061 T6 extruded angle. Note the curved inside vertex.
I have had to drill using a dimpled part before. Buy a section of brass tubing (1/16") that perfectly fits the dimpled hole. Use it as a drill bushing to keep the bit centered.#41 should fit.
Hope it works out.
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  #4  
Old 01-01-2019, 07:20 PM
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wjb wjb is offline
 
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Location: Half Moon Bay, CA
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Ryan and I spoke on the phone (we are both local NorCal builders) ... my assessment, too is it's just a longeron replacement. I'm hoping we can find a local supplier with stock so to nix the surely huge shipping charges...

We'll hear what Van's sez tomorrow.
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Last edited by wjb : 01-01-2019 at 07:24 PM.
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  #5  
Old 01-01-2019, 07:20 PM
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Draker Draker is offline
 
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Location: Livermore, CA
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Quote:
Originally Posted by Kyle Boatright View Post
Can you not "simply" replace the longerons? Most everything else is already match hole punched and should fit right back together.
Yea, I'm hoping that's it. If it's just new longerons I'm going to be relieved. All of the non pre-punched parts (lower longeron, aux. longeron, side skin stiffener angle, floor stiffeners) are in the forward area, which hopefully the incorrect bend does not affect.
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Livermore, CA
https://stiletto.smugmug.com/RV7
Donated 1/2/2019
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N12VD reserved!
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  #6  
Old 01-01-2019, 08:05 PM
pilotkms pilotkms is online now
 
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Location: WARNER ROBINS, GA
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Look at the bright side - bending the second set of longerons will be much easier than the first. Donít ask how I know.
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  #7  
Old 01-01-2019, 09:31 PM
rackley16 rackley16 is offline
 
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Location: Oceanside, California
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Ryan, I am sure you are in good company as there have been many mistakes made over the years in building many RV's. Someday you will look back and smile about it, I am sure. I have been where you are with other projects and honestly, the worst part was how bad I would beat myself up over it.

I do thank you for having the stones to stand up and show it. Just doing that will help some other guy down the road. That's what this forum is all about. Helping one another.

Good on ya! Ben
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  #8  
Old 01-02-2019, 07:41 AM
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jcarne jcarne is offline
 
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Yep I'm thinking just longerons too. Sorry to hear this happened. Keep us posted.
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  #9  
Old 01-02-2019, 09:54 AM
rapid_ascent rapid_ascent is offline
 
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Ryan,

I sent you an email.

Ray
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  #10  
Old 01-02-2019, 11:56 AM
Girraf Girraf is offline
 
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Location: Southern Maryland
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Quote:
Originally Posted by rackley16 View Post
Ryan, I am sure you are in good company as there have been many mistakes made over the years in building many RV's. Someday you will look back and smile about it, I am sure. I have been where you are with other projects and honestly, the worst part was how bad I would beat myself up over it.

I do thank you for having the stones to stand up and show it. Just doing that will help some other guy down the road. That's what this forum is all about. Helping one another.

Good on ya! Ben
I represent the guy that this guy is talking about. Iíll note your experience to hopefully avoid the same mistake when I get to this part of the build. Iíve also chosen to order two extra longerons with my wing order because I donít trust myself!
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